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914World.com _ 914World Garage _ Aftermarket FI options for Type 4 motors 2056 or larger

Posted by: DRPHIL914 Feb 6 2023, 09:05 AM

i started looking into this 2 years ago when i was planning my rebuild motor after the drpped valve seat on the OEM motor.
I ended up building a nice 2056 with increased compression, brand new heads, counter balanced crank and of course the cam is performance minded as well.
to start i installed the d-jet and later last year i added a 50mm bored out stock throttle body from Tangerine/Chris Foley. Yes this helped a great deal, but we are still limited due to the d-jet and the MPS. So there are a few people out there that make ITB( independant throttle body) that could be used.
One is Jenvey, and i see that PMB is carrying those. It looks ike they are mated to what ever IDF intake manifold you choose. there are 40, 45, 48 options. mated with 350cc injectors.
I am wondering other than the CB performance stuff that has been available for a while, others have come to the table, who here has played around with this ? over the years ive read a lot on others using the megasquirt and micro etc and it seemd they were very difficult to tune and set up with lots of problems, trial and error.

I am looking for advice on what to stay away from and what are the pitfalls and mistakes we can avoid before jumping into this.

Look forward to some input, thanks!!

Phil

Posted by: DRPHIL914 Feb 6 2023, 09:06 AM


forgot to add this link, its the PMB page listing the Jenvey line for /4 and /6 motors

https://pmbperformance.com/products/jenvey-heritage-idf-40-45-or-48mm-for-vw-type-1-or-porsche-914-4?pr_prod_strat=use_description&pr_rec_id=76792b18d&pr_rec_pid=7490339209394&pr_ref_pid=7490097250482&pr_seq=uniform

Posted by: GregAmy Feb 6 2023, 09:30 AM

We have several good discussion topics already going on this.

The Dub Shop (Mario's a super guy) has a bolt-on system. But I think he's having difficulties getting throttle bodies:

https://thedubshop.com/dual-throttle-body-fuel-injection-package-with-ignition-t4-914/

Here's a guide I wrote on my Microsquirt conversion of D-Jet (it's not a quick read*):

https://tgadrivel.blogspot.com/2020/03/on-microsquirting-porsche-914-part-1.html

Search the site and you'll find other projects with Megasquirt and Haltech. - GA

*I did it that way mostly for myself, to remind me WiTH I did and how I got there. But I figure that if you don't have the patience to read through the thing theny ou probably don't have patience to build it... wink.gif

Posted by: DRPHIL914 Feb 6 2023, 09:45 AM

QUOTE(GregAmy @ Feb 6 2023, 10:30 AM) *

We have several good discussion topics already going on this.

The Dub Shop (Mario's a super guy) has a bolt-on system. But I think he's having difficulties getting throttle bodies:

https://thedubshop.com/dual-throttle-body-fuel-injection-package-with-ignition-t4-914/

Here's a guide I wrote on my Microsquirt conversion of D-Jet (it's not a quick read*):

https://tgadrivel.blogspot.com/2020/03/on-microsquirting-porsche-914-part-1.html

Search the site and you'll find other projects with Megasquirt and Haltech. - GA

*I did it that way mostly for myself, to remind me WiTH I did and how I got there. But I figure that if you don't have the patience to read through the thing theny ou probably don't have patience to build it... wink.gif


@http://www.914world.com/bbs2/index.php?showuser=15565

thanks for the response, i know Ethan down in jax florida started his build with the Haltec conversion using all stock parts. If Mario is having trouble getting what every ITB he was using( i had read that a while ago) then its time to find other options of ITB's that can be used which along with control systms was a reason i started this tread. Most guys seems are using other stock stuff. I will certainly give a full read thru your thread. Zach just posted on another thread someon was posting asking about his 2056 build and CR, etc that he was using 44 ITB with his , that was a another question what sized to use with a similar engine, 40's or 44's. 48's seem too large for ITB FI, . Too expensive to just buy them and get the totally wrong thing,.

Phil

Posted by: GregAmy Feb 6 2023, 09:53 AM

Well, thinking outside the box, there's no reason why you can't build a system that uses Dell or Weber carbs for airflow control with the injectors installed in the manifold. I know I've seen those drilled manifolds somewhere but can't find the link now...

Mario's also got a new source for ITBs - he uses/used CB Performance prior - and I'm actually waiting for a pair of 36s to try on my street car:

https://thedubshop.com/dual-idf-throttle-bodies-outside-injectors-vwss/

Just a "play with it" test, as it should be as easy as replacing the induction and using the same fuel and electrical systems. I don't expect any significant power improvements, as I'm not currnetly seeing any significant reduction in MAP (maybe 95kPA?) even at WOT at 5500 RPM redline (point is, I think the stock D-Jet flows "enough" air now.) If found to be reasonably true, then it makes building a D-Jet-based conversion a lot easier, and a lot cheaper.

GA

Posted by: Geezer914 Feb 6 2023, 10:10 AM

2056, 9:1 CR. 9550 cam, 50mm vanagon throttle body. Running 1.8L jet with the AFR metering wheel richened up 4 knotches.

Posted by: rgolia Feb 6 2023, 01:48 PM

I am looking hard at this as I am getting tired of the gas smell and hard starts. It seems like the dub-shop has pre-orders going on. Should I take the plunge? PMB? The dub shop? Decisions....decisions.

Posted by: 914Sixer Feb 6 2023, 02:05 PM

Currently sold out but more on the way.


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Posted by: GregAmy Feb 6 2023, 04:11 PM

You can do that. I just decided to use the stock rails and securing hardware using these injectors...they should look familiar...

https://www.fiveomotorsport.com/high-impedance-hose-type-fuel-injector-bmw-jaguar-porsche/

I replaced the straight lines with curved ones from 914Rubber (or was it Pelican? I forget).


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Posted by: billh1963 Feb 6 2023, 04:18 PM

Probably a stupid question but are Holley sniper and similar systems too big for the Type IV? With 4 bbl intake "manifolds" available seems like that could work (if not too big).

Posted by: GregAmy Feb 6 2023, 04:35 PM

QUOTE(billh1963 @ Feb 6 2023, 05:18 PM) *

Probably a stupid question but are Holley sniper and similar systems too big for the Type IV? With 4 bbl intake "manifolds" available seems like that could work (if not too big).

Depends on what you want it for and where you want the power band.

I decided on 36mm TBs (times four holes) because my 2056 is a ~9:1 street car with a self-imposed ~5500 redline and I wanted solid low- and mid-range airflow velocity for torque. We'll see how it works out.

If I was installing it on my race car, with more compression and ~6500 hard stop and no care what it does down low, then I might consider 40s, maybe 44s (I currently run 40 Dells with 36mm venturis and it seems pretty darned strong up top, wants to keep going...)

I expected the stock D-Jet induction was not going to be enough for my street car. Frankly, maybe it isn't. But I've yet to see any indications via the MAP that it's struggling for air with the stock throttle body. - GA

Posted by: 914werke Feb 6 2023, 06:35 PM

Ive talked to those guys, it seems the real value of those rail kits is the ability to use newer non-EV1 injectors.

Posted by: JamesM Feb 6 2023, 07:19 PM

QUOTE(DRPHIL914 @ Feb 6 2023, 08:05 AM) *

Look forward to some input, thanks!!

Phil


You can run aftermarket FI without going ITBs and unless your motor absolutely needs the ITBs then you are probably better off avoiding them. Your issue isnt so much going to be the lack of airflow with the d-jet intake so much as it is the lack of adjustability with the fueling and timing. Aftermarket injection on top of stock intake. Less cost to build, easier to tune, most likely more drivable as well. Added bonus, it retains the stock appearance and uses less aftermarket parts.


QUOTE(GregAmy @ Feb 6 2023, 03:35 PM) *

I expected the stock D-Jet induction was not going to be enough for my street car. Frankly, maybe it isn't. But I've yet to see any indications via the MAP that it's struggling for air with the stock throttle body. - GA


agree.gif
If your motor is near stock or a mild performance build you will save yourself a lot of money and effort sticking with stock 1.8 or 2.0 intake plumbing (Not 1.7 though). An aftermarket ECU will always be an improvement over d-jet but no real need to change the induction plumbing unless you are planning on 140+ hp or a larger displacement 2270 etc

Posted by: MSGGrunt Feb 6 2023, 07:24 PM

I have converted my 1969 TR6 with twin SU side draft carbs to FI using a kit made by Patton Machine in Maine and also converted a 1973 Mercedes 2.8 I6 using a 2-barrell EFI system by FI Tech, similar to the Holley sniper system and I have a few questions.

With the Jenvey system is there any risk of the fuel falling out of atomization before it reaches the intake at the head? Does it get input from the stock Porsche sensors? My car is a 1975 CA car, so it originally had an O2 sensor.


With the FI Tech system the 2-barrel is bolted on in place of the OEM Mercedes Solex 4A1 4-barrel. All the "brains" of the system are internal to the unit except for an O2 sensor that had to be installed.

https://fitechefi.com/product/39001-go-efi-2-barrel-400hp-system/


On the Patton Machine system, he uses a GM computer with GM injectors and the SU carbs as just a means to flow air. It comes with a separate O2 sensor, TPS, IAC, MAP, and coolant temp sensors, so not a single unit like the FI Tech or Holley Sniper.

https://www.pattonmachine.com/shop/https-www-pattonmachine-com-shop-triumph-tr6-six-6-cylinder-engine-throttle-body-injection-kit-with-distributor-conversion-ignition-mapping-for-two-2-small-or-medium-bodied-carbs/


Like others, I like my fuel injection even if L-jetronic isn't state of the art by today's standards, but what are we to do if we want to take our 1.8 motors out to 2.0? I assume it would be more than just swapping in bigger injectors and installing a larger or bored our throttle body?






Posted by: mihai914 Feb 7 2023, 07:46 AM

QUOTE(billh1963 @ Feb 6 2023, 05:18 PM) *

Probably a stupid question but are Holley sniper and similar systems too big for the Type IV? With 4 bbl intake "manifolds" available seems like that could work (if not too big).


It's a valid question and I think the main issue with the Sniper EFI systems is that you lose the port injection and revert to a throttle body injection which will cause fuel atomization problems due to the long runners.

The 4 bbl might be too big but they do offer a 1bbl that may or may not fit in place of the throttle body on a 2.0 setup.

https://www.holley.com/products/fuel_systems/fuel_injection/sniper_efi/sniper_efi_autolite_1100_one_barrel/parts/550-552

Posted by: mihai914 Feb 7 2023, 08:04 AM

QUOTE(rgolia @ Feb 6 2023, 02:48 PM) *

I am looking hard at this as I am getting tired of the gas smell and hard starts. It seems like the dub-shop has pre-orders going on. Should I take the plunge? PMB? The dub shop? Decisions....decisions.


I think that one of the most important aspects when going with non OE setups, even more so for a complex system like the FI, is support for that system. You want the vendor to be there for you when you will have issues, not just answering the phone but to be able to help with the technical side of things.

D-Jet has stuck around for so long because you can get parts (new and used) or have them refurbished and there is plenty of support from manuals, websites and people here.

Microsquirt, Megasquirt, SDS, Motec, etc. and the customization of the engine make it such that you are basically the only person that is able to service the FI.

Finally, many of the pro Type 4 engine builders still stick to carbs, I think they have gone through the path of trying to make EFI work on a bigger scale.

Food for thought, it's a cool project.

Posted by: emerygt350 Feb 7 2023, 08:33 AM

If it were me, I would see if the stock FI will work first. The djet is tuneable to a large extent if you have an afr gauge and tangerine racings upgrades to the MPS. People above have mentioned a few turns on the old Ljet made it work with a bigger engine and other improvements.

If original Fi performance can't do it, I think I would go a couple of potential routes. I kind of like the idea of 2x1barrel holley's on custom intakes. Each could have its own bank o2 sensor. Not sure if they would be happy working like that but it might work.

Another move might be seeing if holly or fi tech has moved into that port injection setup they have for V8s. If they have a version for a 4 cylinder you could potentially keep everything the same and pop on the throttle body and injectors. All kinds of potential issues there with sizes etc. but I would look.

I like the idea of a completely self contained setup so I would probably not bother looking at other cars systems if it were me.

Posted by: Superhawk996 Feb 7 2023, 08:58 AM

QUOTE(mihai914 @ Feb 7 2023, 08:46 AM) *

QUOTE(billh1963 @ Feb 6 2023, 05:18 PM) *

Probably a stupid question but are Holley sniper and similar systems too big for the Type IV? With 4 bbl intake "manifolds" available seems like that could work (if not too big).


It's a valid question and I think the main issue with the Sniper EFI systems is that you lose the port injection and revert to a throttle body injection which will cause fuel atomization problems due to the long runners.

The 4 bbl might be too big but they do offer a 1bbl that may or may not fit in place of the throttle body on a 2.0 setup.



Throttle body injection (TBI) is the worst version of fuel injection. Not even a step up from carbs in my opinion. You get the complexity of fuel injection with all the disadvantages of carbs.

As mentioned above - atomization, fuel drop out in the runners are major issues. You also don’t have control over fuel distribution. Fuel simply goes where it goes. Some cylinders will get more fuel than others.

Then there are mass flow effects. Having the fuel injected that far away from the cylinder creates a large time delay between the time the fuel is injected and when it gets to the cylinder. That delay affects throttle response negatively. Not much of a problem on lumbering V8’s. Not good for high reving small displacement engine’s that change engine speed more quickly.

VW & Porsche (and most other European OEMs) had the common sense to avoid TBI and go straight to port injection. The domestics were too embedded in the past and didn’t want to retool new manifolds, wiring, etc. and went for the cheap solution of TBI. When emissions could no longer be met with TBI, they were forced to go to port injection.

Don’t ignore history.


Posted by: emerygt350 Feb 7 2023, 10:35 AM

I work with early tbi (CFI in the ford world). It really is better than carbs by a long shot. Poor fuel distribution is a manifold issue (just like carbs). Mpi is better of course but I wouldn't go bragging up our bank fire system. Runner length is still up in the air for me. Velocities are so high and engine heat eventually gets there as well. Obviously mpi would be better but I just don't by it as a show stopper. Modern mpi engines can have incredibly long runners.

Posted by: DRPHIL914 Feb 7 2023, 10:57 AM



ok wow lots of great comments here i just got caught up reading it all-
this company i have known about- for a while , so i reached out to them again today, and they had an issue with their mounts. i am looking at this if i were to avoid the ITB’s and just get a programmable FI system but stay with my 50mm throttle bud and kept the direct injector, but have new improved bosch injectors that go with these fuel rails. seems keeping direct injection is best, and 50mm probably getting me plenty of air, i have an AFR ans it seems i have enough fuel although at WOT it feels like it needs more ans does go more lean, thst is so hard to change with D-jet it can’t be mapped out lik you could with a more modern FI ECU.
so maybe the Haltec EXU ans sensors to go with my stock intake runners ans 50mm TB ,
would not be a lot of $$,
Injector rehab has one set of rails and injectors, but have to make a new retaining bracket for it, so i’m drying to work out a deal with them and get that, going to look into SDS, Haltec, and get with Eric about their system they have for 2056/2270 motors they developed . not sure which ECU they use.

Phil


QUOTE(914Sixer @ Feb 6 2023, 03:05 PM) *

Currently sold out but more on the way.


Posted by: Aerostatwv Feb 7 2023, 11:02 AM

I thought there is a difference with injectors. The d-jet uses low impedance injectors vs. modern FI that use a high impedance injector?

Posted by: Superhawk996 Feb 7 2023, 12:22 PM

QUOTE(emerygt350 @ Feb 7 2023, 11:35 AM) *

I work with early tbi (CFI in the ford world). It really is better than carbs by a long shot.


By what metric?

Emissions - Agreed. TBI was a response to inability to meet emissions regulations.

Lack of jets and small air passages to clog - sure. But now you add other sensors and actuators to system with their own associated failure modes.

Performance - no so much.

Long runners on modern engines are a function of them only having air flow in them and the fuel delivered at the intake port. Long runners of a 914 that are largely isolated from the engine will take much longer to warm up than an aluminum manifold bolted directly to heads nestled down in the valley of a V8. Not to mention the nasty, nearly 180 degree turn the air fuel mix has to make to enter the intake port of a 914. That turn is a recipe for fuel to fall out of suspension as it slams into the wall of the runner. Fuel has mass and it wants to travel in straight line rather than execute a 180 degree turn. Physics and all that.

Virtually all the performance gains of the last 30 years came from the benefits associated with port injection and direct ignition. Precision control over fuel and spark. TBI and an antique distributor isn’t optimal.

In my opinion, there is no point in taking the trip to get rid of D-jet / L-jet or even a set of well tuned carbs to land at TBI on a 914 T4 engine. Too much hassle for too little gain.

Posted by: Superhawk996 Feb 7 2023, 12:30 PM

QUOTE(DRPHIL914 @ Feb 7 2023, 11:57 AM) *

seems keeping direct injection is best


Totally know what you meant.

Keeping fuel injection terminology clean, direct injection is yet another incarnation of fuel injection. But now with the fuel being injected directly into the combustion chamber at sky high pressures. 914’s don’t have direct injection.

Typical multi port injection is sub - 100 psi range.

Direct Injection is at several thousand psi.

Posted by: Superhawk996 Feb 7 2023, 12:36 PM

QUOTE(Aerostatwv @ Feb 7 2023, 12:02 PM) *

I thought there is a difference with injectors. The d-jet uses low impedance injectors vs. modern FI that use a high impedance injector?

True

There are resistor packs that can enable The use low low impedance injectors.

Posted by: Jack Standz Feb 7 2023, 01:03 PM

QUOTE(emerygt350 @ Feb 7 2023, 11:35 PM) *

I work with early tbi (CFI in the ford world). It really is better than carbs by a long shot. Poor fuel distribution is a manifold issue (just like carbs). Mpi is better of course but I wouldn't go bragging up our bank fire system. Runner length is still up in the air for me. Velocities are so high and engine heat eventually gets there as well. Obviously mpi would be better but I just don't by it as a show stopper. Modern mpi engines can have incredibly long runners.

+1

(not bragging about the bank fire system nor unfairly cricising an almost 60 year old system, but someday would like a better FI system that doesn't require gobs of $$, hours & hours of fabrication, and an intensive understanding of engineering and electronics to make it work right, just saying)

Maybe a dual TBI system with appropriate length intake manifolds would be an improvement over what many are running now? Maybe I'm dreaming, but the idea of bolting on a couple intake manifolds and throttle bodies & hooking up some sensors (OK, welding on a couple O2 sensor bungs) sounds really good to me right now especially after restoring, rebuilding and tuning a couple Dellorto carbs.

Posted by: Superhawk996 Feb 7 2023, 01:32 PM

What is with with the love of TBI?

Sure dual TBI on custom manifolds would be better than running a singular TBI through stock 914 manifolds.

But what have you gained?

Now you have a linkage that needs to be synchronized. Just like dual carbs. Just like dual ITB’s running multi port injection.

Now maybe need two TBI ECUs to manage two TBI’s? Now you have all the disadvantages of what has basically become an ITB setup with its issues of low and unstable vacuum signal to run a MAP sensor off of.

Dual TBI would need custom intake manifolds. At least current T4 ITB - multiport setup uses commercially available manifolds from Weber / Dellorto setup.

TBI is not some sort of magical fuel injection system that is inherently easier to tune than a multi port setup.

Am I missing something? I promise I don’t hate TBI but it is inferior to multi port injection. TBI was an emissions band-aid for a short window of time in automotive history. I’m not seeing how it makes life any easier when installed on a 914.

Posted by: rhodyguy Feb 7 2023, 01:43 PM

A local member had a big T4 and I think he used the FI from a later model Mustang.

Posted by: rbzymek Feb 7 2023, 02:01 PM

I worked at Ford in the engine controls department during the Carb/TBI/MAP Port Injection/Mas air Meter Port Injection time frame. Port injection is far superior to TBI for the reasons given by superhawk996. For a 2056 street car you can't beat an L-Jet system with a Vanagon throttle body. It uses a vane meter to measure airflow and can easily be adjusted to run slightly rich with an AFR meter.

Posted by: mihai914 Feb 7 2023, 02:46 PM

QUOTE(Superhawk996 @ Feb 7 2023, 02:32 PM) *

What is with with the love of TBI?

Sure dual TBI on custom manifolds would be better than running a singular TBI through stock 914 manifolds.

But what have you gained?

Now you have a linkage that needs to be synchronized. Just like dual carbs. Just like dual ITB’s running multi port injection.

Now maybe need two TBI ECUs to manage two TBI’s? Now you have all the disadvantages of what has basically become an ITB setup with its issues of low and unstable vacuum signal to run a MAP sensor off of.

Dual TBI would need custom intake manifolds. At least current T4 ITB - multiport setup uses commercially available manifolds from Weber / Dellorto setup.

TBI is not some sort of magical fuel injection system that is inherently easier to tune than a multi port setup.

Am I missing something? I promise I don’t hate TBI but it is inferior to multi port injection. TBI was an emissions band-aid for a short window of time in automotive history. I’m not seeing how it makes life any easier when installed on a 914.


I don't think it's a love of TBI necessarily, it's convenience and ease of execution. If you look at our use of technology in general, it's rarely the best technology available that prevails in the mass market.

Sniper EFI, FiTEch and all other similar products are appealing because they self tune, are mostly self-contained, are bolt-on in their specific applications and are not much more expensive vs. a equivalent performance carburetor.

I would be very surprised that racing teams, of all kinds, would use the above mentioned products, but for the common backyard mechanic, it does the job well.

Personally, when I look at the BugShop's offer, the kit looks well put together, but then you have to specify if you want help with tuning. I understand that the vendor can not sell a one for all type of system, and that he can't be profitable if he were to support every customer for free. It's just that at some point, you want to take something out of the box, bolt it to the car and go driving.

As for a SniperEFI type of thing, I get a nice screen and probably get to play with just enough parameters for my level of knowledge.

Posted by: JamesM Feb 7 2023, 03:19 PM

QUOTE(mihai914 @ Feb 7 2023, 01:46 PM) *


Sniper EFI, FiTEch and all other similar products are appealing because they self tune, are mostly self-contained, are bolt-on in their specific applications and are not much more expensive vs. a equivalent performance carburetor.

I would be very surprised that racing teams, of all kinds, would use the above mentioned products, but for the common backyard mechanic, it does the job well.



Using the term "Self Tune" is along the lines of saying Teslas can "Self Drive" In fact I would probably say of the two that "Self Driving" requires a lot less human interaction.

Its a great sales pitch, but still requires setup and only works as well as the operator directing it.

Posted by: Superhawk996 Feb 7 2023, 03:38 PM

QUOTE(JamesM @ Feb 7 2023, 04:19 PM) *

Using the term "Self Tune" is along the lines of saying Teslas can "Self Drive"

laugh.gif agree.gif

I get the appeal of self tune but it’s not there yet. Just go look at the number of people having issues with Sniper running too rich, stalling, having EMI type issues, etc. I get that having the ECU in the TBi package is nice - no dispute there. Sniper still needs a good vacuum signal to run and engine temp signal.

TunerStudio for MegaSquirt offers an “auto tune” functionality that will greatly help in tuning but it still isn’t full auto tuning.

The reality of EFI is that somehow, you are going to have to learn to “tune” what you have. No different than learning to tune carbs properly.

Even with all the power of AI and latest processors in ECU’s the OEM’s still employ calibration engineers to do the final tuning and much of it is done on road to get production calibrations.

Expecting a magic “self tune” capability out of a $1k product is going to leave you disappointed. Probably even more so when trying to apply it to the quirks of air cooled engines that run hotter than water pumpers and prefer to run on the rich side to keep the heads cool enough to not drop valve seats.

Posted by: Jack Standz Feb 7 2023, 03:38 PM

QUOTE(Superhawk996 @ Feb 8 2023, 02:32 AM) *

What is with with the love of TBI?

Sure dual TBI on custom manifolds would be better than running a singular TBI through stock 914 manifolds.

But what have you gained?

Now you have a linkage that needs to be synchronized. Just like dual carbs. Just like dual ITB’s running multi port injection.

Now maybe need two TBI ECUs to manage two TBI’s? Now you have all the disadvantages of what has basically become an ITB setup with its issues of low and unstable vacuum signal to run a MAP sensor off of.

Dual TBI would need custom intake manifolds. At least current T4 ITB - multiport setup uses commercially available manifolds from Weber / Dellorto setup.

TBI is not some sort of magical fuel injection system that is inherently easier to tune than a multi port setup.

Am I missing something? I promise I don’t hate TBI but it is inferior to multi port injection. TBI was an emissions band-aid for a short window of time in automotive history. I’m not seeing how it makes life any easier when installed on a 914.


"Now you have a linkage that needs to be synchronized. Just like dual carbs. Just like dual ITB’s running multi port injection."

Why can't you run a drive by wire system? You know, to address the synchronization pblm?

"Dual TBI would need custom intake manifolds. At least current T4 ITB - multiport setup uses commercially available manifolds from Weber / Dellorto setup."

So? Doesn`t seem so difficult a fabrication problem for any vendor that I'd be willing to purchase Type IV manifolds from. As you point out, IDF manifolds require customization for MPFI anyway.

"TBI is not some sort of magical fuel injection system that is inherently easier to tune than a multi port setup."

Honestly, was hoping the self-learning modes of some of these systems could be incorporated to make installing and running such a system inherently easier. Of course a magical system might be even better smile.gif.

"I promise I don’t hate TBI but it is inferior to multi port injection."

I don't hate FI either. But, the point is maybe a slightly "inferior" system that is more reasonable in cost and less time consuming to install/run has a certain appeal to us non-enginneers and non-electronic gurus.

Best wishes for your next fuel delivery system and induction methodology.


Posted by: emerygt350 Feb 7 2023, 03:46 PM

QUOTE(mihai914 @ Feb 7 2023, 03:46 PM) *

QUOTE(Superhawk996 @ Feb 7 2023, 02:32 PM) *

What is with with the love of TBI?

Sure dual TBI on custom manifolds would be better than running a singular TBI through stock 914 manifolds.

But what have you gained?

Now you have a linkage that needs to be synchronized. Just like dual carbs. Just like dual ITB’s running multi port injection.

Now maybe need two TBI ECUs to manage two TBI’s? Now you have all the disadvantages of what has basically become an ITB setup with its issues of low and unstable vacuum signal to run a MAP sensor off of.

Dual TBI would need custom intake manifolds. At least current T4 ITB - multiport setup uses commercially available manifolds from Weber / Dellorto setup.

TBI is not some sort of magical fuel injection system that is inherently easier to tune than a multi port setup.

Am I missing something? I promise I don’t hate TBI but it is inferior to multi port injection. TBI was an emissions band-aid for a short window of time in automotive history. I’m not seeing how it makes life any easier when installed on a 914.


I don't think it's a love of TBI necessarily, it's convenience and ease of execution. If you look at our use of technology in general, it's rarely the best technology available that prevails in the mass market.

Sniper EFI, FiTEch and all other similar products are appealing because they self tune, are mostly self-contained, are bolt-on in their specific applications and are not much more expensive vs. a equivalent performance carburetor.

I would be very surprised that racing teams, of all kinds, would use the above mentioned products, but for the common backyard mechanic, it does the job well.

Personally, when I look at the BugShop's offer, the kit looks well put together, but then you have to specify if you want help with tuning. I understand that the vendor can not sell a one for all type of system, and that he can't be profitable if he were to support every customer for free. It's just that at some point, you want to take something out of the box, bolt it to the car and go driving.

As for a SniperEFI type of thing, I get a nice screen and probably get to play with just enough parameters for my level of knowledge.


Exactly.

Would I use tbi on a race engine? Possibly. Australian Ford made some impressive CFI race cars. Would I dismiss it because mpi, no, just as no one completely gives up on carbs because fi. It really is an elegant solution. Particularly when it is all self contained. Just a couple of 02 sensors and off you go.

Posted by: Superhawk996 Feb 7 2023, 03:56 PM

Fair points but let me address throttle by wire.

Drive by wire is but another level of complexity on top of EFI. It was about a decade of the OEMs running conventional cable operated throttles with EFI before they moved to throttle by wire.

The safety implications of moving to throttle by wire are staggering. Every prototype I’ve ever tested in has a huge red emergency stop button that kills all power - just in case anything goes haywire with throttle by wire.

Throttle by wire may seem like the “easy button” but it is anything but easy.

Posted by: mihai914 Feb 7 2023, 04:04 PM

QUOTE(Superhawk996 @ Feb 7 2023, 04:38 PM) *

QUOTE(JamesM @ Feb 7 2023, 04:19 PM) *

Using the term "Self Tune" is along the lines of saying Teslas can "Self Drive"

laugh.gif agree.gif

I get the appeal of self tune but it’s not there yet. Just go look at the number of people having issues with Sniper running too rich, stalling, having EMI type issues, etc. I get that having the ECU in the TBi package is nice - no dispute there. Sniper still needs a good vacuum signal to run and engine temp signal.

TunerStudio for MegaSquirt offers an “auto tune” functionality that will greatly help in tuning but it still isn’t full auto tuning.

The reality of EFI is that somehow, you are going to have to learn to “tune” what you have. No different than learning to tune carbs properly.

Even with all the power of AI and latest processors in ECU’s the OEM’s still employ calibration engineers to do the final tuning and much of it is done on road to get production calibrations.

Expecting a magic “self tune” capability out of a $1k product is going to leave you disappointed. Probably even more so when trying to apply it to the quirks of air cooled engines that run hotter than water pumpers and prefer to run on the rich side to keep the heads cool enough to not drop valve seats.


Tough crowd biggrin.gif

To quote myself:

As for a SniperEFI type of thing, I get a nice screen and probably get to play with just enough parameters for my level of knowledge.

I don't think any member here gobs the whole self tuning marketing, I take it as a starting point instead of loading a map downloaded somewhere.

Not all of us are engineers or want to play for hours with a laptop. Some of us are willing to leave some HP or torque on the table and just go driving.

What I would like as a potential customer, is for a vendor (with the help of an engineer preferably) to offer me a product that takes most of the guesswork out of the equation.

It's a great thread with a healthy debate and I hope we have vendors looking at it because it's a free focus group.

Posted by: GregAmy Feb 7 2023, 04:14 PM

QUOTE(Superhawk996 @ Feb 7 2023, 04:56 PM) *

The safety implications of moving to throttle by wire are staggering. Every prototype I’ve ever tested in has a huge red emergency stop button that kills all power - just in case anything goes haywire with throttle by wire.

Ditto. I designed and installed an AEM DBW engine management system on our '08 Civic Si race car (using factory DBW components) and I made sure my kill switch is big and read and easily accessible by the monkey.

And while it removes the aggravation of possibly breaking a throttle cable and being stuck (how often does that happen?) it really doesn't offer much advantage*. I would not be comfy doing DBW in my 914. - GA

*I suspect, but certainly cannot prove, that the driving force for throttle DBW came from the mid-80s Audi "runaway" issue, and later a Toyota Camry(?), where drivers were insisting that they were smashing on the brakes but the cars kept going. It was ultimately suspected - but not proven - that the drivers were either actually pushing on the throttle instead, or more likely pushing on both, but not on the brakes as hard as they thought they were.

DBW fixed that: if you're on the throttle and brake for more than "x" seconds, even lightly, the throttle is brought back to idle.

My first experience with that was doing an HPDE in my new '00 Audi S4 while trying to left-foot-brake through the middle of the corner to balance the chassis and keep the turbos spooled; car kept going back to idle. Pissed me off royally... biggrin.gif

Posted by: Superhawk996 Feb 7 2023, 04:38 PM

beer3.gif The initial Audi unintended acceleration in the 80s led to brake / shifter interlock switches so that you could not put in Drive unless you 1st had your foot on the brake pedal.

Been there - lived that. Shift cable interlocks and clutch pedal switches suck.

Throttle by wire really came about for the following reasons:

1) Throttle by wire preempts driver control over the throttle blade. Example: when engine is running lean on highway cruise, the driver mashing the pedal to the floor no longer results in the throttle blade going wide open throttle resulting in further leaning out and a stumble and loss of power at the wrong instant. Throttle by wire opens the throttle for the driver in proportion to how quickly EFI can add fuel without resulting in the usual over rich mix that you get during hard accelerations by just dumping in lots of fuel open loop in response to an instant WOT by the driver.

Throttle by wire was a big aid to managing fuel economy, emissions, and catalyst temperatures. It was also very useful to help control what we used to call “Buck & Bobble” on manual transmissions where you get an unwanted feedback loop between an inexperienced drivers throttle control and the vehicle lurching due to poor clutch control.

2) Throttle by wire enables Electronic Stability Control (ESC) that was being mandated by NHTSA and EU on SUVs and high Cg vehicles. There were early attempts at ESC via spark and fuel control to cut and manage engine power but they didn’t have enough fidelity. When a stability control event occurs - stability control takes responsibility for throttle and brake commands. Cutting power too quickly can cause unwanted forward weight transfer leading to vehicle rollover. Too little power cut means the brakes are fighting driven axles.

Posted by: Superhawk996 Feb 7 2023, 04:41 PM

The Toyota unintended acceleration issue was a result of throttle by wire’s existence. Drivers claimed that the vehicle went Wide Open Throttle on them even though they were not pressing on the gas pedal.


Although that claim of throttle by wire running haywire was later dismissed, that is the sort of thing that I meant by staggering safety implications.

This Toyota case (and others) is among the primary reason we now have electronic data recorders (many with camera images captured) in modern vehicles. Basically a post crash black box to know exactly what you were doing in the final moments before you crashed. Think of it as a liability limiter for the OEMs and a great data set for the police to use against you if need be.

Posted by: mihai914 Feb 7 2023, 05:11 PM

Food for thought:

https://www.holley.com/blog/post/adapting_a_sniper_efi_system_to_a_vintage_volkswagen/

Posted by: Superhawk996 Feb 7 2023, 05:21 PM

QUOTE(mihai914 @ Feb 7 2023, 06:11 PM) *

Food for thought:

https://www.holley.com/blog/post/adapting_a_sniper_efi_system_to_a_vintage_volkswagen/

Encouraging but only proves the point that you’re going to be left to tune it.

“I think I changed just about every parameter in that EFI program to make it work. But I really like that the Sniper system self-tunes as long I provide it with the right targets and parameters for these engines, and keeps itself tuned.”

confused24.gif I’m just missing it. Self tunes - ummm OK.

But not to be dense, I get the desire to buy it from a guy like this that figures it out and then can offer it to customers with some expectation that it’s plug and play.

What gets lost in the noise is that for it to work plug and play, your engine will need to be very close in specification and in good health to have a chance of it working within the boundaries defined for that particular engine configuration.


Posted by: Jack Standz Feb 7 2023, 06:45 PM

Well, I don't know how Edelbrock got it to work (or addressed the safety issues discussed above), but back in 2015 they put together this manifold that can use two DBW throttle bodies:

https://www.edelbrock.com/cross-ram-ls3-intake-manifold-7141.html

Was seriously looking at getting one for an LS4 motor eventually going into a Fiero, but they don't offer it for the cathedral heads (and it's pricey, although less now than when introduced). So, it's not a type iv motor, but could be considered a proof of concept for using dual DBW throttle bodies on one motor.

And of course you can always fool around with trying to use mechanical throttle bodies and mechanical linkage if the DBW ones give you heartburn.




Posted by: Superhawk996 Feb 7 2023, 07:29 PM

QUOTE(Jack Standz @ Feb 7 2023, 07:45 PM) *

Well, I don't know how Edelbrock got it to work (or addressed the safety issues discussed above), but back in 2015 they put together this manifold that can use two DBW throttle bodies:

https://www.edelbrock.com/cross-ram-ls3-intake-manifold-7141.html



They didn’t. They are selling you a manifold. If that manifold happens to fit GM throttle bodies that operate throttle by wire, so be it.

It’s up to you to figure out how to make the throttle bodies work. If you use a GM ECU that’s a coincidence. In the end, Edelbrock will bear no responsibility for what the end user does with their parts.

If they were selling a complete, functional system inclusive of an ECU and software they would open themselves up to functional safety implications and potential liability. Even then I’m not sure.

Currently there is a company CommaAI that is basically selling a way to hack your car to create or modify Level 2 ADAS features that can affect driver and vehicle safety. As of yet, there has been no accident or litigation. When the time comes, they will claim the driver was ultimately responsible for the vehicle safety and that they only made the hardware and the code available. How it at will turn out in court is yet to be seen.

From install PDF:
“NOTE: Proper installation is the responsibility of the installer. Improper installation may result in poor performance and engine or vehicle damage.”

Surprised it doesn’t also have the usual “for off-road use only” disclaimer too.

Posted by: emerygt350 Feb 7 2023, 07:30 PM

No fun car of mine is in spec. And they both have the stock fi systems that I have had to tune by hand. It's all about how hard that is and a
Sniper systems are actually engineered to deal with exactly that problem. Again, not that it will be better, but I think it would be good.

I put a four barrel Edelbrock manifold under my 2 barrel HO CFI in my mustang for two reasons. One, it's a far better manifold for the application than the original cast iron 2 barrel truck intake (Ford, you suck..), and when my computer fails and I can't replace the half dozen sensors, I can just pop a Holley sniper on top. It won't care what cam I have, what head I have or what exhaust I put on.

That is not something to scoff at. That's one afternoon and I am driving again. With about 60 more HP from what I can gather from friends in the ford world.

Posted by: Superhawk996 Feb 7 2023, 07:53 PM

Was reading the Holly quick start guide. This guide also applies to 914 wiring and should be should be pinned. av-943.gif

Attached Image

If you feel any of these are appropriate wiring - EFI is not for you happy11.gif

Posted by: bkrantz Feb 7 2023, 09:12 PM

I have the Dub Shop kit on my 2056. As delivered it was easy to install and set up, and it started and idled on the first attempt with the default Type 4 tune file Mario included. After one dyno session I consider the tune 90-95% complete. I hope to get the remaining 5% this summer as I learn how to tweak the Megasquirt settings.

Posted by: emerygt350 Feb 8 2023, 07:24 AM

superhawk, that is awesome. However, I have had a cheap pair of crimpers like that for decades! Nobody steals your crimpers if they look like that.

and it's missing my patented "I can't find the electrical tape, so I guess this yellow lab tape is just going to have to work" method.

Posted by: DRPHIL914 Feb 8 2023, 07:51 AM

QUOTE(bkrantz @ Feb 7 2023, 10:12 PM) *

I have the Dub Shop kit on my 2056. As delivered it was easy to install and set up, and it started and idled on the first attempt with the default Type 4 tune file Mario included. After one dyno session I consider the tune 90-95% complete. I hope to get the remaining 5% this summer as I learn how to tweak the Megasquirt settings.


thats awesome!

So the Holley system is what PMB has now gone to , you can use stock components for intake ant TB or go with manifolds and ITB . either way you have a new self learning ECU and new injectors and coils that are basically stock for a small block chevy, they are making the modification brackets for the modern new Bosch TPS and temp sensor to be mounted on our existing plenum . much easier than having to deal with the linkage issues for running separate bank of ITB's. also better to have the air temp and flow measured from one TB than multiple.

I would assume that the new system runs high impedence injectors so new ones are necessary but previlent and cheaper. This could be the quick and easy swap 914 ownders have been looking for with a FI system for less than a set of carbs.

Posted by: rgolia Feb 8 2023, 11:52 AM

QUOTE(DRPHIL914 @ Feb 8 2023, 08:51 AM) *

QUOTE(bkrantz @ Feb 7 2023, 10:12 PM) *

I have the Dub Shop kit on my 2056. As delivered it was easy to install and set up, and it started and idled on the first attempt with the default Type 4 tune file Mario included. After one dyno session I consider the tune 90-95% complete. I hope to get the remaining 5% this summer as I learn how to tweak the Megasquirt settings.


thats awesome!

So the Holley system is what PMB has now gone to , you can use stock components for intake ant TB or go with manifolds and ITB . either way you have a new self learning ECU and new injectors and coils that are basically stock for a small block chevy, they are making the modification brackets for the modern new Bosch TPS and temp sensor to be mounted on our existing plenum . much easier than having to deal with the linkage issues for running separate bank of ITB's. also better to have the air temp and flow measured from one TB than multiple.

I would assume that the new system runs high impedence injectors so new ones are necessary but previlent and cheaper. This could be the quick and easy swap 914 ownders have been looking for with a FI system for less than a set of carbs.


So what's your plan Phil?

Posted by: rgolia Feb 8 2023, 11:53 AM

QUOTE(bkrantz @ Feb 7 2023, 10:12 PM) *

I have the Dub Shop kit on my 2056. As delivered it was easy to install and set up, and it started and idled on the first attempt with the default Type 4 tune file Mario included. After one dyno session I consider the tune 90-95% complete. I hope to get the remaining 5% this summer as I learn how to tweak the Megasquirt settings.


Did you have carbs prior to installing the dub shop kit? If so, what are the benefits. That is not a cheap kit, but I am seriously considering it.

Posted by: DRPHIL914 Feb 8 2023, 12:57 PM

QUOTE(rgolia @ Feb 8 2023, 12:52 PM) *

QUOTE(DRPHIL914 @ Feb 8 2023, 08:51 AM) *

QUOTE(bkrantz @ Feb 7 2023, 10:12 PM) *

I have the Dub Shop kit on my 2056. As delivered it was easy to install and set up, and it started and idled on the first attempt with the default Type 4 tune file Mario included. After one dyno session I consider the tune 90-95% complete. I hope to get the remaining 5% this summer as I learn how to tweak the Megasquirt settings.


thats awesome!

So the Holley system is what PMB has now gone to , you can use stock components for intake ant TB or go with manifolds and ITB . either way you have a new self learning ECU and new injectors and coils that are basically stock for a small block chevy, they are making the modification brackets for the modern new Bosch TPS and temp sensor to be mounted on our existing plenum . much easier than having to deal with the linkage issues for running separate bank of ITB's. also better to have the air temp and flow measured from one TB than multiple.

I would assume that the new system runs high impedence injectors so new ones are necessary but previlent and cheaper. This could be the quick and easy swap 914 ownders have been looking for with a FI system for less than a set of carbs.


So what's your plan Phil?

@http://www.914world.com/bbs2/index.php?showuser=11329
my plan now is to work with PBM to source the conversion parts they have developed, adaptors to mount the sensors, obtain the FI ECU(Holley) , and for now will
using the stock intakes and my 50MM TB on the stock plenum.

once ican do all that i will save up to eventually get the ITB from PMB(JenveyHeritage IDF 40//45)

Posted by: DRPHIL914 Feb 8 2023, 12:57 PM

QUOTE(rgolia @ Feb 8 2023, 12:52 PM) *

QUOTE(DRPHIL914 @ Feb 8 2023, 08:51 AM) *

QUOTE(bkrantz @ Feb 7 2023, 10:12 PM) *

I have the Dub Shop kit on my 2056. As delivered it was easy to install and set up, and it started and idled on the first attempt with the default Type 4 tune file Mario included. After one dyno session I consider the tune 90-95% complete. I hope to get the remaining 5% this summer as I learn how to tweak the Megasquirt settings.


thats awesome!

So the Holley system is what PMB has now gone to , you can use stock components for intake ant TB or go with manifolds and ITB . either way you have a new self learning ECU and new injectors and coils that are basically stock for a small block chevy, they are making the modification brackets for the modern new Bosch TPS and temp sensor to be mounted on our existing plenum . much easier than having to deal with the linkage issues for running separate bank of ITB's. also better to have the air temp and flow measured from one TB than multiple.

I would assume that the new system runs high impedence injectors so new ones are necessary but previlent and cheaper. This could be the quick and easy swap 914 ownders have been looking for with a FI system for less than a set of carbs.


So what's your plan Phil?

@http://www.914world.com/bbs2/index.php?showuser=11329
my plan now is to work with PBM to source the conversion parts they have developed, adaptors to mount the sensors, obtain the FI ECU(Holley) , and for now will
using the stock intakes and my 50MM TB on the stock plenum.

once ican do all that i will save up to eventually get the ITB from PMB(JenveyHeritage IDF 40//45)

Posted by: mihai914 Feb 8 2023, 01:20 PM

QUOTE(DRPHIL914 @ Feb 8 2023, 08:51 AM) *

QUOTE(bkrantz @ Feb 7 2023, 10:12 PM) *

I have the Dub Shop kit on my 2056. As delivered it was easy to install and set up, and it started and idled on the first attempt with the default Type 4 tune file Mario included. After one dyno session I consider the tune 90-95% complete. I hope to get the remaining 5% this summer as I learn how to tweak the Megasquirt settings.


thats awesome!

So the Holley system is what PMB has now gone to , you can use stock components for intake ant TB or go with manifolds and ITB . either way you have a new self learning ECU and new injectors and coils that are basically stock for a small block chevy, they are making the modification brackets for the modern new Bosch TPS and temp sensor to be mounted on our existing plenum . much easier than having to deal with the linkage issues for running separate bank of ITB's. also better to have the air temp and flow measured from one TB than multiple.

I would assume that the new system runs high impedence injectors so new ones are necessary but previlent and cheaper. This could be the quick and easy swap 914 ownders have been looking for with a FI system for less than a set of carbs.


@http://www.914world.com/bbs2/index.php?showuser=11106

Do you have a link to PMBs Type4 Holley adaptation?

The Terminator X seems to tick alot of the right boxes.

Thanks

Posted by: DRPHIL914 Feb 8 2023, 01:36 PM

QUOTE(mihai914 @ Feb 8 2023, 02:20 PM) *

QUOTE(DRPHIL914 @ Feb 8 2023, 08:51 AM) *

QUOTE(bkrantz @ Feb 7 2023, 10:12 PM) *

I have the Dub Shop kit on my 2056. As delivered it was easy to install and set up, and it started and idled on the first attempt with the default Type 4 tune file Mario included. After one dyno session I consider the tune 90-95% complete. I hope to get the remaining 5% this summer as I learn how to tweak the Megasquirt settings.


thats awesome!

So the Holley system is what PMB has now gone to , you can use stock components for intake ant TB or go with manifolds and ITB . either way you have a new self learning ECU and new injectors and coils that are basically stock for a small block chevy, they are making the modification brackets for the modern new Bosch TPS and temp sensor to be mounted on our existing plenum . much easier than having to deal with the linkage issues for running separate bank of ITB's. also better to have the air temp and flow measured from one TB than multiple.

I would assume that the new system runs high impedence injectors so new ones are necessary but previlent and cheaper. This could be the quick and easy swap 914 ownders have been looking for with a FI system for less than a set of carbs.


@http://www.914world.com/bbs2/index.php?showuser=11106

Do you have a link to PMBs Type4 Holley adaptation?

The Terminator X seems to tick alot of the right boxes.

Thanks

no links sorry, they do not have it listed yet , they have not mass produced all the parts yet but this may light a fire under them to do so, but they have a lot going on.

if they don’t have the time or personnel to do that one thought i have is to get all the parts - with eric’s approval, thst they are making , get them scanned so they can be reproduced and start getting some kits together. I will soon have a list/spreadsheet of everything , building this right now and will go from there.
as i get thing ans collect specific part numbers and sources i will post .


Posted by: GeorgeKopf Feb 8 2023, 02:45 PM

Has anybody looked at Simple Digital Systems for aftermarket EFI?

http://www.sdsefi.com/specific.html

Attached Image

The kit does not include:
Fuel injectors
Fuel pressure regulator
Fuel rail
Fuel pump
Fuel return line from regulator to fuel tank
Throttle body

George

Posted by: scott_in_nh Feb 8 2023, 04:37 PM

QUOTE(GregAmy @ Feb 6 2023, 10:30 AM) *

We have several good discussion topics already going on this.

The Dub Shop (Mario's a super guy) has a bolt-on system. But I think he's having difficulties getting throttle bodies:

https://thedubshop.com/dual-throttle-body-fuel-injection-package-with-ignition-t4-914/

Here's a guide I wrote on my Microsquirt conversion of D-Jet (it's not a quick read*):

https://tgadrivel.blogspot.com/2020/03/on-microsquirting-porsche-914-part-1.html

Search the site and you'll find other projects with Megasquirt and Haltech. - GA

*I did it that way mostly for myself, to remind me WiTH I did and how I got there. But I figure that if you don't have the patience to read through the thing theny ou probably don't have patience to build it... wink.gif


@http://www.914world.com/bbs2/index.php?showuser=15565 That was a good read - thanks for taking the time to put it together!
So let me ask you this:
Let's say you already have a 123 distributor with the FI points that you are happy with - could you use one or both of the triggers as a cam/crank position sensor with Microsquirt? The obvious benefit being that you do not have to take the engine out to to fit a trigger wheel (or to change a bad sensor). If possible I think it might really simplify the changeover to Microsquirt and a lot of guys already have them installed.....
Scott

Posted by: GregAmy Feb 8 2023, 04:57 PM

QUOTE(scott_in_nh @ Feb 8 2023, 05:37 PM) *
That was a good read - thanks for taking the time to put it together!

You are most welcome. Did you actually make it through the whole thing?

QUOTE
Let's say you already have a 123 distributor with the FI points that you are happy with - could you use one or both of the triggers as a cam/crank position sensor with Microsquirt?

I don't know a lot of about the 123 or how the factory system triggers the injectors...however, WAG'ing it from the stock DJet computer diagram, I think not.

If I'm reading that diagram correctly, the disty simply provides a "fire now" signal to one of two banks (stock DJet is batch injection) with no logic. Disty triggers open or close like points (or is it Hall Effect?), computer does some electrical magic, and the injectors fire.

Microsquirt (all pretty much all EFI), on the other hand, wants to know where the crankshaft is relative to TDC and from that, and your desired tuning, it calculates timing and fires the injectors; DJet triggers can't provide that, they're a binary signal.

Doesn't mean you can't continue to use the 123 disty and ignition coil if you want to, they'll run fine. But once the MS is installed it's only a few more components to remove the disty (and sell it) and put an EFI-driven coil on it. An EFI-driven coil also which allows you to vary timing based on RPM and load. - GA


Attached thumbnail(s)
Attached Image

Posted by: scott_in_nh Feb 8 2023, 05:25 PM

QUOTE(GregAmy @ Feb 8 2023, 05:57 PM) *

QUOTE(scott_in_nh @ Feb 8 2023, 05:37 PM) *
That was a good read - thanks for taking the time to put it together!

You are most welcome. Did you actually make it through the whole thing?


I did! It took two sessions only because I didn't have the time to do it in one!

Too bad it won't work, it could have been a great intermediary step.

Posted by: mihai914 Feb 8 2023, 07:33 PM

Ok, to keep the ball rolling, can we also talk about options in general and cost?

Let's consider that all these options need "tuning" to different extents.

For example:

Option 1 - Rebuild D-Jet addressing most common problems/wear items (No ignition)

RockAuto New injectors - $300
Restoration Design New Harness - $480
Jeff Bowlsby MPS Rebuild + basic calibration - $474
Jeff Bowlsby ECU testing - $150
914 Rubber TPS board - $52

Total - $1456

Option 2 - PMB Dual 34 ICT Carbs - $610

Option 3 - PMB Dual 40 IDF Carbs - $1180

Option 4 - DubShop Complete EFI with ignition - $4080

Option 5 - Holley terminator X or similar setup - $1249 as a starting point for the basic hardware...

I consider the DubShop system, the ultimate upgrade but can't justify the cost for a stock or home built 2056 (personal opinion).

I never worked on carbs except for small engines and it's a step back for a stock engine with stock cam.

Rebuilding D-jet seems fairly easy except to fine tune the MPS.

The off the shelf system could be a nightmare or could become plug and play if there is vendor or community support. Final cost is unknown for now and depends how far you exploit the system.

Questions:

A: What is your tipping point $$$ to put D-Jet in a box and start fresh?
B: How much time are you willing to spend to install and setup the system?
C: Which option would you be willing to help a 914 buddy if he offered a bbq dinner and some beer?

Please feel free to add options.

Posted by: mepstein Feb 8 2023, 08:28 PM

Installing FI is never cheap. People always underestimate the amount of tuning and sorting needed to make even a plug and play system actually run well. Not just cost but time. And plug and play rarely is.
My personal opinion is if you want FI, buy the best system you can, find someone who knows how to tune it and close your eyes when it’s time to swipe the credit card.

Posted by: bkrantz Feb 8 2023, 09:09 PM

QUOTE(rgolia @ Feb 8 2023, 10:53 AM) *

QUOTE(bkrantz @ Feb 7 2023, 10:12 PM) *

I have the Dub Shop kit on my 2056. As delivered it was easy to install and set up, and it started and idled on the first attempt with the default Type 4 tune file Mario included. After one dyno session I consider the tune 90-95% complete. I hope to get the remaining 5% this summer as I learn how to tweak the Megasquirt settings.


Did you have carbs prior to installing the dub shop kit? If so, what are the benefits. That is not a cheap kit, but I am seriously considering it.


No, my non-running engine had the original D-jet, but with lots of questionable components and beat up wires and connectors. I rationalized the price of the Dub Shop kit with guesses how much I could spend to repair the D-jet. Plus I wanted the programability (and the sexy ITB stacks).

I think I am getting more power out of my build, and smoother running. The biggest flaw in the Dub Shop kit is the lack of a separate cold start circuit. Not too important to me, but could be for some.

Posted by: r_towle Feb 8 2023, 10:54 PM

Last time I looked at this CBPerformance sold complete kits.

Lately I have been looking for EFI on a six cylinder, and the options for generic throttle bodies are many, with adapters for lots of different engines.
Bore size is an option
All the stuff is now out there, including Coil on Plug tech

Rich

Posted by: rgolia Feb 9 2023, 08:40 AM

QUOTE(bkrantz @ Feb 8 2023, 10:09 PM) *

QUOTE(rgolia @ Feb 8 2023, 10:53 AM) *

QUOTE(bkrantz @ Feb 7 2023, 10:12 PM) *

I have the Dub Shop kit on my 2056. As delivered it was easy to install and set up, and it started and idled on the first attempt with the default Type 4 tune file Mario included. After one dyno session I consider the tune 90-95% complete. I hope to get the remaining 5% this summer as I learn how to tweak the Megasquirt settings.


Did you have carbs prior to installing the dub shop kit? If so, what are the benefits. That is not a cheap kit, but I am seriously considering it.


No, my non-running engine had the original D-jet, but with lots of questionable components and beat up wires and connectors. I rationalized the price of the Dub Shop kit with guesses how much I could spend to repair the D-jet. Plus I wanted the programability (and the sexy ITB stacks).

I think I am getting more power out of my build, and smoother running. The biggest flaw in the Dub Shop kit is the lack of a separate cold start circuit. Not too important to me, but could be for some.


@http://www.914world.com/bbs2/index.php?showuser=23343

I am seriously looking at the dubshop system. This car is like a family member having it since new, so I will do my best to swipe the credit card with out swallowing to hard. The engine was rebuilt a few years ago at Tangerine Racing, 2056 with new AA heads done by Hoffman. It runs great, but cold and warm starts suck and the fuel smell is getting old. Right now it is running with 44 webers and there is no existing FI stuff left in the car as far as I know.

So is this the place that you started and how much time did it take to install and tune. Please provide details. I can deal with the spend but I cant deal with frustration and not being able to drive the car because I get the thing dialed in.

Posted by: Superhawk996 Feb 9 2023, 08:48 AM

agree.gif

Like rgolia, I’ve leaned toward DubShop . Mario has a dyno. He seems to provide a reasonable base tune to start from, etc. Sells as a nice complete kit.

I’d really like to know about low speed, off idle drive ability using Alpha-N or hybrid tuning if you know which is being used. Even if you don’t know or haven’t played yet with tuning, what are your impressions of driveability at low throttle?

Regarding cold start circuit, if you mean a Weber type choke circuit, I’m confused. With EFI you should be able to tune injector pulse with by temperature. So if ambient temp (or head temp) is cold, cold, like 20F, you should be able to modify the fuel map and just dump in some extra fuel

Posted by: mihai914 Feb 9 2023, 10:45 AM

I found this thread specifically about the Dub Shop system:

http://www.914world.com/bbs2/index.php?showtopic=211929&st=0

Almost ten years has gone by!

Posted by: bkrantz Feb 9 2023, 09:03 PM

QUOTE(rgolia @ Feb 9 2023, 07:40 AM) *

QUOTE(bkrantz @ Feb 8 2023, 10:09 PM) *

QUOTE(rgolia @ Feb 8 2023, 10:53 AM) *

QUOTE(bkrantz @ Feb 7 2023, 10:12 PM) *

I have the Dub Shop kit on my 2056. As delivered it was easy to install and set up, and it started and idled on the first attempt with the default Type 4 tune file Mario included. After one dyno session I consider the tune 90-95% complete. I hope to get the remaining 5% this summer as I learn how to tweak the Megasquirt settings.


Did you have carbs prior to installing the dub shop kit? If so, what are the benefits. That is not a cheap kit, but I am seriously considering it.


No, my non-running engine had the original D-jet, but with lots of questionable components and beat up wires and connectors. I rationalized the price of the Dub Shop kit with guesses how much I could spend to repair the D-jet. Plus I wanted the programability (and the sexy ITB stacks).

I think I am getting more power out of my build, and smoother running. The biggest flaw in the Dub Shop kit is the lack of a separate cold start circuit. Not too important to me, but could be for some.


@http://www.914world.com/bbs2/index.php?showuser=23343

I am seriously looking at the dubshop system. This car is like a family member having it since new, so I will do my best to swipe the credit card with out swallowing to hard. The engine was rebuilt a few years ago at Tangerine Racing, 2056 with new AA heads done by Hoffman. It runs great, but cold and warm starts suck and the fuel smell is getting old. Right now it is running with 44 webers and there is no existing FI stuff left in the car as far as I know.

So is this the place that you started and how much time did it take to install and tune. Please provide details. I can deal with the spend but I cant deal with frustration and not being able to drive the car because I get the thing dialed in.



For all the gory details, check my build thread, from Sept 2021 to Feb 2022. My dyno tune session was July 2022. I was doing other rebuild work at the same time, so my timeline is complicated. I would bet installing just the EFI kit could be done in about 40 hours.

You will need to embrace tuning with Megasquirt software. It takes a bit to get it set up and learn the basics, but the help manual is OK, and there is lots of stuff online. And you need to decide to pursue tuning by trial and error, or spend the money for some hours (3-6) on a dyno with an operator who knows Megsquirt.

Mario was very good to work with. During the set-up for my dyno session, we ran into a problem and Mario responded to my call for help immediately and saved the session.

BTW, I also have Hoffman heads.

Posted by: GregAmy Mar 24 2023, 01:57 PM

Just a quick bump to report a new "find".

Dude pops up on Facebook, in the Porsche 914World group, just bought a 914 and asking "what is this?" with a photo of what looks like an ECU mounted in the rear trunk. I look at it closely and swear that it's a Honda OBD0 ECU. He sends me a closer photo and YEP it's a Honda P06 OBD0 ECU, circa 1993-1995 1.5L Honda del Sol.

He posts a video of the engine compartment and the car is clearly running a Honda disty (with the square bumpout for the coil/ignitor inside) and Honda wiring harness connectors.

It's a blue car, based in Northern California. I suggested to him that he post here but is anyone familar with the car and the engine management design? I'm wondeirng who did it and how.

If you're in that group you should be able to see this...

https://www.facebook.com/groups/402029799831413/permalink/6574386602595671/

Posted by: jd74914 Mar 24 2023, 07:55 PM

That’s wild. Had to have been done in the late 90s by a heavy duty Hondata guy or something. I can’t imagine ever doing something so complicated in the 2000s when MS and a lot of other budget EFI systems really started taking off.

Posted by: bkrantz Mar 24 2023, 08:54 PM

QUOTE(rgolia @ Feb 9 2023, 08:40 AM) *

QUOTE(bkrantz @ Feb 8 2023, 10:09 PM) *

QUOTE(rgolia @ Feb 8 2023, 10:53 AM) *

QUOTE(bkrantz @ Feb 7 2023, 10:12 PM) *

I have the Dub Shop kit on my 2056. As delivered it was easy to install and set up, and it started and idled on the first attempt with the default Type 4 tune file Mario included. After one dyno session I consider the tune 90-95% complete. I hope to get the remaining 5% this summer as I learn how to tweak the Megasquirt settings.


Did you have carbs prior to installing the dub shop kit? If so, what are the benefits. That is not a cheap kit, but I am seriously considering it.


No, my non-running engine had the original D-jet, but with lots of questionable components and beat up wires and connectors. I rationalized the price of the Dub Shop kit with guesses how much I could spend to repair the D-jet. Plus I wanted the programability (and the sexy ITB stacks).

I think I am getting more power out of my build, and smoother running. The biggest flaw in the Dub Shop kit is the lack of a separate cold start circuit. Not too important to me, but could be for some.


@http://www.914world.com/bbs2/index.php?showuser=23343

I am seriously looking at the dubshop system. This car is like a family member having it since new, so I will do my best to swipe the credit card with out swallowing to hard. The engine was rebuilt a few years ago at Tangerine Racing, 2056 with new AA heads done by Hoffman. It runs great, but cold and warm starts suck and the fuel smell is getting old. Right now it is running with 44 webers and there is no existing FI stuff left in the car as far as I know.

So is this the place that you started and how much time did it take to install and tune. Please provide details. I can deal with the spend but I cant deal with frustration and not being able to drive the car because I get the thing dialed in.


If you read through my build thread, you can see details about the mechanical installation, setting up the fuel lines and wiring, how I mounted the ECU, the pre-start setup (including tune software), the initial start and home tuning, and then my session on a dyno. That all happened over about 6 months (with other build stuff at the same time). I would guess it could all be done in about a month.

Posted by: GregAmy Mar 24 2023, 08:55 PM

QUOTE(jd74914 @ Mar 24 2023, 08:55 PM) *

That’s wild. Had to have been done in the late 90s by a heavy duty Hondata guy or something. I can’t imagine ever doing something so complicated in the 2000s when MS and a lot of other budget EFI systems really started taking off.

Yep, I'm thinking it's a much older build because he says there's no external USB port on the ECU. That indicates it's a socketed EEPROM, well before the Hondata S300 era, so probably late 90s/early 00s. Probably Moates.

I just think it's pretty damned cool that someone went to all that trouble to engineer a D-Jet install to use the (probably) Moates-programmable Honda ECU. I guess when you think about that era, that was about as good as it was for tuneable ECUs...hell, I was doing it with Nissan back then (early 00s) and I thought I was the s**t...that's old school classic rocker stuff; we're not worthy... - GA

Posted by: jd74914 Mar 25 2023, 05:04 AM

agree.gif That stuff really was ahead of it’s time.

That’s before my time-I would have been in elementary school or middle school when people were really playing with socketed EEPROM. laugh.gif First I’d seen if that stuff was when a buddy bought a modded CRX in high school with a newer motor and S300.

Posted by: GregAmy Mar 25 2023, 05:44 AM

QUOTE(jd74914 @ Mar 25 2023, 06:04 AM) *

That’s before my time-I would have been in elementary school or middle school...

All right young-uns, let me tell you how we used to connect to GENie with a device that made enough noise to get your momma's attention as to why you weren't in bed already... beerchug.gif

Definitely "old school". D-Jet (and L-Jet) were so far ahead of their time that full ECU control was, really, still in the future (many don't realize that the mighty 956s Motronic engine management system was a derivative). This came for the fore in the early- to mid-90s with OBD, some systems using pressure (Druck for D-Jet) some using air flow meter (Luft for L-Jet).

Those ECU-controlled cars finally became affordable used cars in the late 90s, and that's when ECU hacking took off. Socketed EEPROMs were the only way to go at the time. You'd find someone to solder in a socket on your board, buy multiple EEPRMs, connect an EEPROM to your computer using an RS232 device, burn the EEPROM. Insert, dyno test. Look at the results, grab another EEPROM to burn with the new tune, swap them, dyno test. Then do it all over again. Tedious.

My first experience with it was in racing with the SR20-equpped Nissan B13s. We weren't even using wideband feedback or data acquisition yet so we'd grab feedback from the driver on where the O2 was down the longest straight and *maybe* take the time to retune the EEPROM, always leaving the weekend's baseline EEPROM off to the side just in case we mucked it up. Even the software was primitive and fidgety to learn. It was right about that time, circa 2005 or so, that guys like CalumSult that tried USB connection and companies like DIYAutotune started offering replacement ECUs (their PnP series) that had USB ports for tuning. Hondata S300. And then eventually wideband feedback, and some times realtime tuning! Life was good.

So I'd really like to meet the guy or gal that did that P06 install into the 914. It was sharp engineering. And I like the way they were thinking! - GA

Posted by: r_towle Mar 25 2023, 09:16 AM

Back about 15,years ago, I tuned a 2.4 liter to 150 hp, dyno tested at the wheels. I used stock djet.
It turned into a big argument with a certain aircooled engine “expert” who falsely claimed it could never be done.
It can be done.
The MPS and the right resistor in the CHT circuit, along with an 02 sensor to measure results is what is required.
We used a dyno at the end to see how close we got…. But most of the tuning was up and down my street.
Djet runs rich, and can made much richer if required.

After I learned the two basic things to tune, I got almost 50 mpg from a 1.7….
Djet was also used on Volvos and a few others.
I ended up trying all the MPs units from those, we settled back on the 914 one and learned how to tune it.
Best way is with an 02 sensor stuffed up the tail pipe.
I own the djet tester, but it is just a break fix tool.

If I was going to do it again I would use the inline exhaust sensors Foley came up with to measure each exhaust port.


Rich

Posted by: targa72e Mar 25 2023, 10:24 PM

Not quite 914 FI related but Porsche related. I replaced the CIS on my 78 911 SC with a later 3.2 Carrera manifold and injectors using the injection system from a Nissan 280ZX. I tweeked the barn door AFM and coolant temp sensor to tune the fuel mixture. It worked well. This was in the early 90's with limited affordable aftermarket ECU's. Worked good for years. I eventually replaced it with a FAST programmable system designed for Chevy's. That FAST system from the 90's and the Carrera intake is still running on my friends 911 today.

john

Posted by: VaccaRabite Mar 27 2023, 06:23 AM

One of the things I'd be wary of with the Dub Shop kit is that it does not (at least when I looked at it) have any ability to run an ICV (Idle Control Valve) or an IAC (Idle Air Control). In my journey with Microsquirt, that's been a critical piece of the puzzle to keep idle steady and starts somewhat smooth.

You CAN do it without the ICV/IAC/whatever you want to call it. For a while I removed the IAC and just used the bleed valve on the TB to manage idle - similar to how D-Jet did it. It works fine once the car is warmed up fully. But getting started on a chilly damp day was challenging that way. And until the engine warmed up it was also a challenging drive, as you need to use throttle to raise idle speed.

Using stock components or using the dual throttle bodies makes the IAC interesting to implement. My solution was kinda janky but it works using a 3d printed connector that attaches a Hyundai IAC from the airbox to the Plenum, suspended on a stout hose. But in my opinion, its a really critical piece of a smooth running FI system. Its also part of the system on just about every modern car.

Zach

Posted by: Geezer914 Mar 27 2023, 09:31 AM

Search for a used Ljet system. You can adjust the AFM with the wheel inside.

Posted by: ClayPerrine Mar 27 2023, 10:57 AM

QUOTE(Geezer914 @ Mar 27 2023, 10:31 AM) *

Search for a used Ljet system. You can adjust the AFM with the wheel inside.



L-Jet is a good system. But it has some limitations that modern EFI doesn't. L-Jet cannot handle any kind of radical camshaft. The flap in the airflow meter starts oscillating badly due to the cam overlap, and that is detrimental to proper mixture control, and makes the air flow meter wear out rapidly.

That's one of the big reasons that Porsche went from a vane air meter in the 964( like the L-Jet has) to a Mass airflow sensor in the 993. And that's the reason I am going away from the 964 motronic in my car. I have a huge, unresolvable flat spot off idle due to the vane air meter oscillation.

I could have gone to a 993 motronic, but the Megasquirt MS3Pro is actually cheaper and gives me more control over the engine.


Posted by: GregAmy Mar 27 2023, 11:19 AM

QUOTE(VaccaRabite @ Mar 27 2023, 07:23 AM) *

One of the things I'd be wary of with the Dub Shop kit is that it does not (at least when I looked at it) have any ability to run an ICV (Idle Control Valve) or an IAC (Idle Air Control). In my journey with Microsquirt, that's been a critical piece of the puzzle to keep idle steady and starts somewhat smooth.

@http://www.914world.com/bbs2/index.php?showuser=1435 Zach, I'm controlling idle on my Microsquirt setup using timing advance/retard. Give it 30 seconds of throttle to get the heads warmed up (I'm still working on my cold start up sequence) but then it cores and smooths the idle like a mofo, you'd never know there wasn't an idle air control valve in there.

It's an option within TunerStudio settings and it works really, really well. - GA

Posted by: falcor75 Mar 27 2023, 12:30 PM

QUOTE(ClayPerrine @ Mar 27 2023, 05:57 PM) *

QUOTE(Geezer914 @ Mar 27 2023, 10:31 AM) *

Search for a used Ljet system. You can adjust the AFM with the wheel inside.



L-Jet is a good system. But it has some limitations that modern EFI doesn't. L-Jet cannot handle any kind of radical camshaft. The flap in the airflow meter starts oscillating badly due to the cam overlap, and that is detrimental to proper mixture control, and makes the air flow meter wear out rapidly.

That's one of the big reasons that Porsche went from a vane air meter in the 964( like the L-Jet has) to a Mass airflow sensor in the 993. And that's the reason I am going away from the 964 motronic in my car. I have a huge, unresolvable flat spot off idle due to the vane air meter oscillation.

I could have gone to a 993 motronic, but the Megasquirt MS3Pro is actually cheaper and gives me more control over the engine.


There is a German company that does an upgrade to the 964 to use the 993 MAF, cant remember what its called at the moment. One thing I love with a stock system is the no nonsense engine start and idle etc. you have to tinker ALOT to get similar performance with an aftermarket system.

Posted by: GregAmy Mar 27 2023, 05:28 PM

QUOTE(GregAmy @ Mar 27 2023, 12:19 PM) *

QUOTE(VaccaRabite @ Mar 27 2023, 07:23 AM) *

One of the things I'd be wary of with the Dub Shop kit is that it does not (at least when I looked at it) have any ability to run an ICV (Idle Control Valve) or an IAC (Idle Air Control). In my journey with Microsquirt, that's been a critical piece of the puzzle to keep idle steady and starts somewhat smooth.

@http://www.914world.com/bbs2/index.php?showuser=1435 Zach, I'm controlling idle on my Microsquirt setup using timing advance/retard. Give it 30 seconds of throttle to get the heads warmed up (I'm still working on my cold start up sequence) but then it cores and smooths the idle like a mofo, you'd never know there wasn't an idle air control valve in there.

It's an option within TunerStudio settings and it works really, really well. - GA


EDIT: got home looked it up. TunerStudio, Startup/Idle, Idle Advance Settings, Change "Idle Advance On" to RPMs. Then Startup/Idle, Idle Advance RPM Settings, and you create a table how you want the timing to change based on RPM.

I have mine set to 15.4@700, 6.7@800, 0@950, -11.9@1100, and -17.9@1250. Cores my idle at 950 really nicely.

Note Startup/Idle, Idle Control, Idle Valve Type is set to "None".

Posted by: jd74914 Mar 27 2023, 11:52 PM

Controlling idle with spark timing is really the way to go in my opinion. It’s pretty prevalent on newer cars (and in the aftermarket most people recommend going this way rather than with an additional IAC setup). It’s similar to how you make sure an AC compressor doesn’t stall a car at idle. I’ve had good success with a timing ‘trough’ controlling idle on some high rev bike race motors, have not done it on a T4 (though sounds like it’s working well for Greg), but it can’t be that much harder since the bike motors have way wilder cams.

Posted by: rick 918-S Mar 28 2023, 01:14 AM

QUOTE(GregAmy @ Mar 27 2023, 06:28 PM) *

QUOTE(GregAmy @ Mar 27 2023, 12:19 PM) *

QUOTE(VaccaRabite @ Mar 27 2023, 07:23 AM) *

One of the things I'd be wary of with the Dub Shop kit is that it does not (at least when I looked at it) have any ability to run an ICV (Idle Control Valve) or an IAC (Idle Air Control). In my journey with Microsquirt, that's been a critical piece of the puzzle to keep idle steady and starts somewhat smooth.

@http://www.914world.com/bbs2/index.php?showuser=1435 Zach, I'm controlling idle on my Microsquirt setup using timing advance/retard. Give it 30 seconds of throttle to get the heads warmed up (I'm still working on my cold start up sequence) but then it cores and smooths the idle like a mofo, you'd never know there wasn't an idle air control valve in there.

It's an option within TunerStudio settings and it works really, really well. - GA


EDIT: got home looked it up. TunerStudio, Startup/Idle, Idle Advance Settings, Change "Idle Advance On" to RPMs. Then Startup/Idle, Idle Advance RPM Settings, and you create a table how you want the timing to change based on RPM.

I have mine set to 15.4@700, 6.7@800, 0@950, -11.9@1100, and -17.9@1250. Cores my idle at 950 really nicely.

Note Startup/Idle, Idle Control, Idle Valve Type is set to "None".


Hey Greg! I have no idea what that means.... But I like it! aktion035.gif

Seriously, I am looking at Microsquirt for our Healey project. running a Suzuki Swift GTI Twin Cam Engine. The heads have builtin port injection and it runs a MAF system. The MAF (Mass Air Flow) system is bulky and ugly. I have 4 Motorcycle carbs I am starting to set up for throttle bodies only. I think it will look more like a carb'd Lotus engine and run like al modern car.

This is a great thread.

What is everyone running for a fuel pump and what do you think of an intank unit?

Posted by: jd74914 Mar 28 2023, 01:31 AM

In tank is the way to go if you can make it work. Pump stays cool all of the time and you remove an out of tank leak point. My favorite setups for normal engines also have the regulator integrated so you don’t need that external either.

With the ITBs you really need to use timing to control idle…IMO at least.

Posted by: ClayPerrine Mar 28 2023, 05:04 AM

QUOTE(jd74914 @ Mar 28 2023, 02:31 AM) *

In tank is the way to go if you can make it work. Pump stays cool all of the time and you remove an out of tank leak point. My favorite setups for normal engines also have the regulator integrated so you don’t need that external either.

With the ITBs you really need to use timing to control idle…IMO at least.



A lot of the aftermarket injection systems are now running no fuel pressure regulator. Instead, they use a fuel pressure sensor, a solid state relay and pulse width modulation of the fuel pump circuit to regulate the pressure. So no pressure regulator and no return line. The ECU controls the fuel pressure and can increase and decrease it as needed for best efficiency.

I am installing a stepper IAC On my ITB setup. The timing changes can only do so much for the idle control. Think of it as the IAC controls the major idle speed changes. Timing fine tunes it.


Posted by: VaccaRabite Mar 28 2023, 05:23 AM

QUOTE(GregAmy @ Mar 27 2023, 07:28 PM) *

QUOTE(GregAmy @ Mar 27 2023, 12:19 PM) *

QUOTE(VaccaRabite @ Mar 27 2023, 07:23 AM) *

One of the things I'd be wary of with the Dub Shop kit is that it does not (at least when I looked at it) have any ability to run an ICV (Idle Control Valve) or an IAC (Idle Air Control). In my journey with Microsquirt, that's been a critical piece of the puzzle to keep idle steady and starts somewhat smooth.

@http://www.914world.com/bbs2/index.php?showuser=1435 Zach, I'm controlling idle on my Microsquirt setup using timing advance/retard. Give it 30 seconds of throttle to get the heads warmed up (I'm still working on my cold start up sequence) but then it cores and smooths the idle like a mofo, you'd never know there wasn't an idle air control valve in there.

It's an option within TunerStudio settings and it works really, really well. - GA


EDIT: got home looked it up. TunerStudio, Startup/Idle, Idle Advance Settings, Change "Idle Advance On" to RPMs. Then Startup/Idle, Idle Advance RPM Settings, and you create a table how you want the timing to change based on RPM.

I have mine set to 15.4@700, 6.7@800, 0@950, -11.9@1100, and -17.9@1250. Cores my idle at 950 really nicely.

Note Startup/Idle, Idle Control, Idle Valve Type is set to "None".


Interesting. I'm assuming the timing retard jumps as soon as touch the throttle?

I know the engine Eric is building also uses an IAC, and its currently a sticking point as you can't get the bodies they plug into. I wonder if his team has looked into controlling idle through timing.

@http://www.914world.com/bbs2/index.php?showuser=1110

Posted by: GregAmy Mar 28 2023, 05:41 AM

QUOTE(VaccaRabite @ Mar 28 2023, 06:23 AM) *

Interesting. I'm assuming the timing retard jumps as soon as touch the throttle?

Haven't really noticed; I can send some logs if you'd like to look it over? But note there's also a setting in "Idle Advance Settings" where you control at what TPS and RPM it's affecting timing; mine is "below 2%" and "below 1200". Anything above that and it's using the ignition map.

I'll offer that this feature is giving me some minor headaches on the Toyota MR2 race car with radical cams. The engine either just wants to die near desired idle using low throttle body bypass (not enough air) or take off with more TB bypass (too much air) and there's not a lot of difference between the two TB settings.

I had to find a middle ground where I opened the bypass a tad more and aggressively pulled back timing below 5% TPS to core the idle at 1500 and set it to pull the idle timing below 2500 RPM (which is fine for a race car that lives at 5000-8000). - GA

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