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Posted by: Mark Henry Feb 17 2021, 10:34 AM

One of the locals fell on some hard times, his plans changed and his 930 was sold, so he offered me a smoking deal on an EFI system.

SDS EM5-F /6 system with twin plug coil packs, Siemens 55lb injectors, cold start valve, crank trigger and /6 trigger mount, extra relay outputs (had meth injection), Beru plug wires X2, manuals, base maps, dizzy hole block off, Bosch one wire (Djet) head temp sender plus all the cabling, fuses, etc that are not included with an SDS system.
I already have a Wabro 300hp FI pump, a Djet fuel pressure regulator, 14point7 wideband O2 meter and an O2 bung in both headers.

This is not a discussion on which Aftermarket EFI system is better, etc but rather on plenum based intake design.
I'm not new. I've been playing with a SDS EM4-F /4 system since 2003-2004 that's now on my '67 bug T4 2600cc conversion, I know that ITB's are better for peak HP, but I'm after overall improvement, usable vacuum signal for MAP, drivability, fuel economy and etc.

FYI I have also asked this on the bird board http://forums.pelicanparts.com/911-engine-rebuilding-forum/1086051-high-performance-plenum-system-aftermarket-efi.html for some more info on the build.
This thread shows my /6 conversion a few years back and has all the engine specs http://www.914world.com/bbs2/index.php?showtopic=229913 Plus I've built my own motorcycle ITB's before http://www.914world.com/bbs2/index.php?showtopic=210004&st=0&p=1862152&#entry1862152.

Please I only want to discuss a single TB plenum based intake for performance EFI.

Posted by: ClayPerrine Feb 17 2021, 10:40 AM

Just buy a 964 intake and throttle body assembly. You will have to make some adapters to hook it to early heads, but it is a very good EFI plenum design. You can even use the SDS to control the resonance flap.

Hope that helps.

Clay

Posted by: Mark Henry Feb 17 2021, 10:49 AM

I could just buy an intake but holy carp have you seen the prices peeps want for 3.6-up Porsche /6 intake? Evil bay I see $600 to 1200 which will be $1000 to $2000 Canadian and I'd still have to fab the injector/head flanges, the TB, clamps, hoses, crossover, etc...so fuchs that.
So unless someone wants to donate a plastic 993 intake or GT3 intake to my cause I think I'm on my own.

Porsche plastic 3.6, is it from a 993 or is this 964?


What I'll likely do is a mild steel manifold similar in construction to some of the aircraft intakes that SDS has made.





But I think I'll keep the two separate intake halves like Porsche does.
Maybe a mustang 75mm TB?

Any one wish to add their 2 cents on a intake design?

Posted by: mepstein Feb 17 2021, 10:56 AM

3.2 Carrera intake. About $500 and good to about 300hp.

Posted by: GregAmy Feb 17 2021, 10:58 AM

Depending on your airflow requirements (total displacement, cams, RPM, etc) I don't think it will be nearly as important on plenum design as it will be for efficient fuel delivery.

For example, we, at our level, don't have the flow bench and aerodynamics knowledge to properly work on resonance, dynamics, blah blah blah. And honestly, for a street engine, it really won't be a significant or noticeable advantage either way, sincer w'ere not playing at the edges.

It can make a difference on how we mount the injectors and deliver the fuel. You won't, for example, want a plenum or TB injection system. But I do like what SDS does on their plenums for that reason.

I'd suggest finding a bolt-on Porsche induction system that has good injector placement, and size a single TB for the WAG'd amount of airflow you'll need for 85% of the time. It'll be a good driveable engine.

Posted by: Mark Henry Feb 17 2021, 10:58 AM

Just looking on the SDS site I can send in my ECU to have the case drilled for a PC input and the cable kit for $135. This will give me full data-logging plus allow me to update the chip via download...so in effect updating to brand new spec.

I'll also need a 1 bar MAP sensor as this has a 2 bar right now.

Posted by: horizontally-opposed Feb 17 2021, 11:19 AM

Porsche, looking for total performance as well as peak performance, moved to a common plenum and never looked back. 3.2 setup is good, 964 and 993 setups better, and latest stuff is better still. Only recently, with the 4.0-liter Speedster and GT3s, has Porsche Motorsport returned to ITBs in a road car. And while they are magical, with what I can only describe as "high-resolution throttle response," there is a lot of tech (and calibration) at work in that magic.

One road that could be of interest is other normally aspirated production flat sixes with plenums of little to no interest to the air-cooled hot-rodders. Fortunately, there are a lot of them, and I suspect there isn't much demand for these parts from salvaged cars. Think Subaru 3.0 flat sixes as well as flat sixes from 986/996, 987/997, and 981/991.1.

Porsche's water-cooled flat sixes had plenums for 2.5, 2.7, 2.9, 3.2, 3.4, 3.6, and 3.8 liters—with and without direct injection depending on displacements—and the plenum doesn't care if an engine is air- or water-cooled. These are light, very nice pieces that were engineered for tight spaces (particularly in Boxsters and Caymans). And if an adapter has to be made to use a later air-cooled plenum, why not make adapters for something even better? And if you can control a resonance flap with SDS…

Posted by: ClayPerrine Feb 17 2021, 11:21 AM

Mark,
there is a 964 complete intake system with throttle body and Idle air controller for US $549.00

https://www.ebay.com/itm/Porsche-911-964-C2-C4-1989-1994-OEM-Plastic-Intake-Manifold-Throttle-Body/233630214188?epid=1024657970&hash=item366572282c:g:U2QAAOSwgMFe9STu


When I got the 964 motor, it had the aluminum intake on it, and it was fried from the engine fire. So I bough this setup and was very happy with it.

Just make 6 injector plates with the correct bolt pattern for your heads.

Clay

Posted by: ClayPerrine Feb 17 2021, 11:25 AM

If you want the aluminum plenum setup I got with my 964 motor, you can have them for the cost of shipping. You will have to clean them up and come up with a throttle body. But it might save you some fab time.


You can see pictures of the intake if you go to my build thread. They are at the beginning.

http://www.914world.com/bbs2/index.php?showtopic=279084

Clay

Posted by: Mark Henry Feb 17 2021, 11:52 AM

Thanks Clay I think I'll take you up on that! Worth it even if I'm just looking at what Porsche did.

I love this community

Posted by: Mark Henry Feb 17 2021, 12:27 PM

I have a 3.4 996 and a 3.8 997.1 manifold here, OK for the basics, center sections, the flap, 1999 has a cable TB, but the runners themselves are spaced too wide.

Posted by: Mark Henry Feb 17 2021, 12:35 PM

Couple of pics of the system.

Posted by: ClayPerrine Feb 17 2021, 01:07 PM

It will take some time for it to warm up outside, and for me to get out in the garage and gather the parts up to send to you.

I will include a set of the 964 injector mount tubes. You may be able to use them to make ones to fit your heads.

Clay

Posted by: jd74914 Feb 17 2021, 01:24 PM

Can't beat that!

Posted by: targa72e Feb 17 2021, 02:50 PM

HI Mark,

I also thought of using the later watercooled Porsche intakes on earlier car as a inexpensive intake. I went as far as to mock it up and it looks doable. You are correct that the later intake is too wide. However it looked like the center tubed could be cut down easily to make the intake narrower. They are connected to each side by rubber tube and clamps so should be easy. you would need to make a adapter to connect the oval tubes of the manifolds to the the round inlet on air cooled head. The intake I have (2.7 boxster I think) has a resonance tube and injector mounts so only would need adapter. I have not taken this any further as I had my friends 2.7RS spec motor with Mod S cams and webers in my 914 for a while and now I am hooked on top end rush of hotter cam. I decided the milder cams for single throttle intake would not cut it and will go ITB. Still might try and use intake over ITB's we will see.

john

Posted by: Steve Feb 18 2021, 09:18 AM

[quote name='Mark Henry'

But I think I'll keep the two separate intake halves like Porsche does.
Maybe a mustang 75mm TB?

Any one wish to add their 2 cents on a intake design?
[/quote]
PRO-M had a 80mm? Mustang MAF kit with MAFTuner for my 3.2. I had it on my car and it did breathe better. At the time I didn’t have a air/fuel gauge and was paranoid, so I took it off. I now have a gauge. The plan is to wire it up and put the MAF back on.
http://www.promracing.com/pro-m-racing-mass-air-meters.html
http://www.mustangandfords.com/how-to/interior-electrical/m5lp-0306-installing-pro-m-maf-tuner

Posted by: Mark Henry Feb 18 2021, 10:14 AM

Cool Steve, do you have any more pics of your intake?
All I need is a TB with a TPS on it, that why I thought of the mustang TB, I'll start looking at sizes.

I'll have to wait a bit on the manifolds, Clay's area is getting hammered with the cold and power problems, obviously I told Clay I'm not in a rush.
Plus I think he has to remember where he put them.

In the meantime I'm going to clean the system up and start planning on where I'm going to mount the ECU, wiring, programmer, etc.
It has the crank trigger on a plate that bolts to the pulley, but it's a two groove pulley and I think my mount only fits a one groove.
So I have lots of little jobs to do.

Posted by: ClayPerrine Feb 18 2021, 10:30 AM

I am going to send the complete intake system, including the injector mounts, and the center section with the throttle body. But the throttle body is fried from the fire.

You will need the rubber boots and the hose clamps, and the fuel rails for the injectors.

Posted by: rick 918-S Feb 18 2021, 10:33 AM

Probably don't have to tell an experienced engine guy like you about this but for others that may not be aware, cam shaft lift and duration are key with EFI. At least with CIS as too much pulse in the intake makes for wacky reactions to drivability. Maybe you can expand on how it effects more modern EFI stuff.

Posted by: Steve Feb 18 2021, 10:41 AM

That’s the only picture I have of the intake. Nothing special all stock 3.2 intake with a mustang MAF to Home Depot sewer pipe to stock boot. Only the stock air flow meter is gone. The under dash MAFTuner adapts the mustang MAF to stock DME computer.

Posted by: ClayPerrine Feb 18 2021, 11:23 AM

There are 3 types of fuel injection.

1. Mass Airflow. This is CIS, L-Jet and it's descendant, DME. It uses an air flow meter or mass air meter to measure the incoming air volume and meter fuel to match. The Vane air meter on L-Jet and CIS is terrible for high performance camshafts. The reversion of the cam overlap makes the air meter flap oscillate back and forth, affecting mixture and eventually breaking the vane air meter. Also, vane air meters are a restriction in the intake tract that reduces horsepower. A Mass airflow meter is better because it doesn't have a flap, but it still is affected by reversion. But careful software programming can tune out the effects of reversion.

2. Speed Density. This is D-Jet and a lot of modern injection systems like GM fuel systems. It measures manifold vacuum to determine the air flow requirements of the engine. It is also affected by reversion, as the cam overlap lowers available manifold vacuum at idle to the point where the ECU is unable to control the mixture effectively.

3. Alpha-N. This is the Bosch MFI system used on early 70s 911s and cars like the BMW 2002Tii and the Porsche 917 that ran at LeMans. It doesn't measure airflow at all, so reversion cannot affect it. It just looks at the position of the throttle and the RPM and uses that to determine the required fuel amount to inject. It will work with any camshaft. But it is horribly inefficient, and it gets lousy fuel mileage. But it has extremely good throttle response and performance. And it has that incredible scream when it is up on the cams and producing horsepower. :shiver:

Modern aftermarket EFI setups like Megasquirt and it's derivatives, can be setup in a hybrid mode, where it will use Alpha-N at low speeds due to reversion, and at higher speeds it will switch to Speed Density or Mass airflow. This allows the engine builder to us radical cams, and still get much better fuel efficiency and performance. The modern EFI can also make a radically cammed engine Idle like a mildly cammed one.

Frankly, the computer chip was the best thing to ever happen to gasoline engines. You can get more HP out of a 2.0L engine that was ever thought possible in the 1960s from a 7.0L monster Chrysler Hemi Elephant motor. As I see it, learning and using modern EFI is the only way to go for performance, drivability and reliability.

My future plans are to megasquirt the 4.0 motor, using the current harness and parts. I will change out the throttle body for a larger one, and to support an integrated idle air motor and throttle position sensor. I will also add wheel speed sensors to the rear wheels so I can use the traction control module. I have considered the idea of ITBs, but I think just a bigger throttle body will be better for street use.

Clay

Clay

Posted by: Mark Henry Feb 18 2021, 11:25 AM

Yes Big cams with big duration equals a poor vacuum signal for the MPS (Manifold Pressure Sensor) adding ITB's (individual throttle bodies) makes the situation even worse. Aftermarket EFI can cope better with this poor vacuum signal but you can push things too far.
My hope is the plenum with a single TB and a vacuum can will give me a more usable signal for the MAP. I also won't have to worry about sync issues with the single TB.

You can get around this by running TPS only, also known as AlphaN, to bypass the MAP but you lose things like altitude correction and the system is more sensitive to pedal inputs, which can be a pain on long trips. But EFI of course wins on fuel mileage. Between having to run in AlphaN or carbs, I think carbs wins on drivability as they're not as touchy to pedal inputs as the EFI in AlphaN.

Posted by: Mark Henry Feb 25 2021, 05:43 PM

Well it looks like Clay can't find his old intake, so I'm on the hunt for a 964 intake.

Thank you for trying to find the intake Clay, especially with the sheet show you guys have been having with the weather.

I sent out the ECU to SDS for the data logging daughter board install, drill case for connector and the adapter cable all for $125.
More importantly than this will allow me to download the current software, before I would have to chip the board to do an upgrade. Basically this turns my used 2012 system into a 2021 ECU.

Posted by: Chris914n6 Feb 25 2021, 08:41 PM

There is a bunch of math involved in a good intake, like the chamber should be the same displacement as the cylinders it feeds. Short runners are good for low and high RPM but long runners do better midrange, thus the split chamber/flap design on most modern cars.

That fab'd one in the pics is horrible.

Making a factory intake fit makes a ton of sense.

Posted by: Mark Henry Feb 26 2021, 07:22 AM

The one in pic's are from an aircraft, I doubt it ever sees over 5krpm even with a reduction drive. The flapper on 911 comes into play at about 5500rpm. I know the math somewhat, I researched this 10 years ago with my big T4 build, but I ended up putting that engine in my VW bug and had to use ITB's.

But the factory intake would save me a ton of work.

Posted by: JamesM Feb 26 2021, 11:43 AM

Look into the feature set of Megasquirts hybrid alpha-N mode, should take care of most if not all of these issues depending on the motor.

Ive run it on an ITBd 2270 and while it is a good deal more complex to initially tune the results are pretty amazing.

Posted by: Carbon-14 Feb 26 2021, 01:54 PM

https://www.youtube.com/watch?v=f5MiS8iLN1I

https://www.youtube.com/watch?v=D-vOstYFhTQ
https://www.youtube.com/c/ThrottleStopGarage/videos
CF Intake Manifold, the road less travelled.
' When you get to a fork in the road, take it '
~ Yogi Berra

Posted by: Mark Henry Feb 26 2021, 02:35 PM

Gee....that's right in the very first post. But I guess there's always that guy.




I already have the SDS EM5-F6 system, not interested in anything else.
I'm not saying SDS is the best, but then MS is isn't as well, honestly I don't give a **** *** what is the best system, that's not the topic.

Posted by: Mark Henry Feb 27 2021, 12:42 PM

Woo Hoo!

I've got two 964 plenum halves on the way, not too far away so I should have them by Friday.
No center section so I might have to do some fabrication.

Something like this ...but I want the reversion flapper

Posted by: Chris914n6 Feb 27 2021, 08:49 PM

Nissan 3.5 (fwd) and 4.0 (trucks) are easy to find. I'm sure others have similar but I know Nissans....

I'd think about 3d printing the tube to fit one in.

Or 996/box should be cheap and easy.

Posted by: Mark Henry Feb 28 2021, 05:18 AM

Thanks for the tip Chris, I wouldn't have thought of looking at a Nissan for that.

Posted by: jd74914 Mar 1 2021, 08:26 AM

Nice!!

Pardon my ignorance, but are the 964 ports same spacing as 2.0+?

Posted by: Mark Henry Mar 1 2021, 09:44 AM

I hope so

This mod has been done before, but mostly for turbos. You have to make new head stubs, in my case a whole new center section.
I'll know more when the two intake halves arrive later this week...I hope.

BTW If anyone wants to do this I think I know where there's another SDS EM5-F6 twinplug (or single plug) system is for sale. Basically a $3000+ EFI and ignition system, plus it includes a wideband gauge, knock sensing and Clewwitt plug wires all for under a $1000.

Posted by: JamesM Mar 1 2021, 02:13 PM

Just throwing it out there as an interesting thing to read up on from a solution standpoint (and possibly a backup plan for anyone with unsolvable drivability issues.) I have zero opinion as to any system being the "best" they are all just different in their feature sets. As long as they get the fuel into the engine in the way you want it... who cares.

I cant offer anything more than theoretical on 6 plenum design as all my first hand experience with that is on the 4s, but that 964 setup looks like the hot ticket. The SDS intake setup looks really nice though i suspect the plenum volume of the one pictured might be less than ideal on a larger engine.

Posted by: Mark Henry Mar 1 2021, 02:40 PM

I believe the plenum formula is used within limitations, a fudge factor, reason #1 is going to be "will it fit" in the engine bay. In this case I imagine the center tubes are counted as part of the plenum volume.

Also I know the EFI system, I have about 18 years experience with an SDS EM4-F4 that I've had on 4 engines. I sold the previous 3 engines, a stock 1.8, 2.0 and a 2.0 with a C25 mild carb cam. This system is currently on my 2600cc Nickies engine, in my '67 bug, that I daily drove till I got my /6 on the road.
I've chipped the EM4 twice so far, I'm debating whether I should chip it again (just over $100) or up grade it to EM5 which is IIRC $500.

The EM5 ECU I'm using for this project I sent in for an data cable upgrade ($125), no more chip, I can download the upgrades.

Posted by: Mark Henry Mar 4 2021, 10:53 AM

So 1 day turn around on my SDS ECU,
Daughter board installed, aluminum case drilled and new connector installed. Kit includes a download cable.
They didn't update my software but they did send me the how to and links. They did save all the map settings that I'll likely change anyways.

I now have full data logging, I'm able to download updates, use different triggers and O2 sensors and a bunch of other small features most l'll likely not use. Ross said it's basically a new ECU.

Now need my 964 intake halves and I can figure out what TB I'm going to use. I have a ford 60mm TB but I've also been looking at Honda TB's.
I want to pick a TB family with the same bolt pattern the has a couple 65mm thru 75mm sizes so I can experiment.

Just measured a 3.6 996 TB and it's 73mm. 3.2 Carrera is 63mm and the 964 3.6 is 68mm.

Posted by: GregAmy Mar 4 2021, 11:14 AM

Mark, what tuning software is used with SDS?

Posted by: Chris914n6 Mar 4 2021, 03:15 PM

They sell generic TBs on ebay. More likely to have the same bolt pattern than different displacement OEMs.

The TB is rarely the limiting factor anyways. I'd just pick one that maths out.

Posted by: Mark Henry Mar 5 2021, 09:16 AM

SDS ??? do you mean the software?

Propitiatory, I'm not sure what they call it, I only see version codes but isn't that the OS? One old chip I have says 4F ver VII, I believe I have a 4F ver XIV (V14) in my old EM4-F4 4cylinder system which you have to chip to upgrade the software.
This 6 cylinder EM5-F6 has a 5F ver 25 chip set, but with the mod I can download the updates, not sure on the newest version code till I download it.

Tuning software like tuner studio?
SDS dosen't need it, you could mess up my fuel and ignition maps and I'll have it started in less than 5 minutes, be driving down the road and have the tuning good enough in 10-15 minutes to go racing , fully tuned in say 20-40 minutes. ( Note I know how to quickly scroll, it may take 3X as long for a beginner. Also doesn't count for finger problems, for storage security I once set a fuel cut at 1000rpm, next spring I forgot that I did this and that was a week of head scratching. doh!)
I ran the SDS on my 1.8 stock engine and for 4 years and except for the initial tune I never once had the programmer on the engine. My first 3 T4 engines I sold as proven running long blocks.

I've been running SDS for 18 years, this will be my 5th personal engine plus I've sold and installed a few systems and I've never had a car on a dyno. I've never seen the need for dyno time.

Posted by: Mark Henry Mar 16 2021, 06:45 AM

My 964 intake halves arrived last night.

I have to figure out the the stubs and center section details, might take a while as I'm super busy restoring 2.0 Djet engines plus other projects this spring/summer. We'll see how much energy I have left over on the weekends.

The SDS EFI install itself only takes a weekend, it's the crank trigger and intake fabrication that sucks up the time.
I could buy off the shelf... but where's the fun in that?


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Posted by: ClayPerrine Mar 16 2021, 06:49 AM

Do you need the stubs, injectors and fuel rails? I have 2 spare sets. I actually pulled out a set for you when I was looking for the manifolds.

Clay

Posted by: Mark Henry Mar 16 2021, 07:00 AM

Question. Does the the 3.2 up intake to ports use phenolic spacers? How thick?

I have 1/4" phenolic spacers under my Weber manifolds and I still have the jigs and material to make another set.

Posted by: Mark Henry Mar 16 2021, 07:05 AM

Hi Clay
Thank you, yes I'll take them, I'll PM you my contact details.

I don't really need the injectors as I have the almost new set that came with my EFI system.

Posted by: ClayPerrine Mar 16 2021, 07:16 AM

I am going to leave them in to hold the fuel rails.

Clay

Posted by: Mark Henry Mar 16 2021, 07:35 AM

Ahhh! Okay then.

Posted by: Mark Henry Mar 18 2021, 11:44 AM

So I'll be making something like below, what way do I orient the plenums and TB ?

I think the pic below is for a 911, do I reverse the plenums to fit the 914?
Which way would you plumb the TB forward or to the rear?

Posted by: Mark Henry Apr 24 2021, 08:56 AM

With all the 2.0 engine work I've taken on I won't make huge progress on my FI project till this coming fall.
The reason I was in no hurry to pop off my webers and BTW I had this years first drive last night.

But....My cheap $70 (Canadian with shipping) Ali-express 70MM TB arrived from China today and it looks good enough. This is a universal TB so it doesn't have extra holes and crap. I'll have to figure out how to do the throttle cable as it looks like the wheel take standard bicycle cable ends.


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Posted by: Mark Henry Apr 24 2021, 09:02 AM

TPS mount doesn't line up with this bosch 3 wire TPS I have, but it fits the D shaft end. It will be easy to make a new mount plate and it will just be a bolt on mod to change the existing mount.
I'll also try a Honda TPS to see if it fits better.


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Posted by: Mark Henry Apr 24 2021, 09:09 AM

The huge bonus is it came with this 9/16" (1.5cm) thick mounting flange (with bolts) that I can weld to the custom center section I will making.

It has an idle stop, but no idle air bypass screw, so I'll have to crack the plate open a bit for idle or another option is to drill a hole in the throttle plate.


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Posted by: Chris914n6 Apr 24 2021, 02:08 PM

This is what I did for mine. https://www.google.com/search?q=barrel+cable+end

Posted by: Mark Henry Apr 24 2021, 03:14 PM

Too big, it's the size of a bicycle cable end which is a little smaller. I might cannibalize another TB for this part.

Posted by: ClayPerrine Apr 24 2021, 08:16 PM

You can't flip the intake manifolds.. they won't fit over the fan shroud if you do. Just tilt the top one down so that it clears the engine lid with the boot on it.

I had mine reversed and the throttle body facing forward, but I found out I need to have it to the rear to get the heater blower hooked up. And a stock 914-6 cable will hook up to the factory 964 throttle body with no issues.

If you need pictures, I can take them.

Clay

Posted by: Chris914n6 May 2 2021, 01:46 AM

Posted by: Mark Henry May 2 2021, 07:43 AM

Cool what's it off of?

I don't know if I even want to use that big wagon wheel on the China TB, it's kind of gawdy looking.
Any rate I'm too busy with other peoples projects and at the moment and my teen is running great on carbs. I took a nice country drive yesterday, woohoo!

Likely I have to pull the engine to do the trigger wheel, I have to pull the pulley to mount the trigger wheel and sensor mount, I'll adjust the valves, address a couple of minor leaks, etc.
I also have to build the center section, once I get caught up here I'll put together a 2.7 as a dummy engine or I'll just wait till my 3.0 is out.

Posted by: Chris914n6 May 2 2021, 01:05 PM

It's been 2 decades but it think it was a Home Depot parts bin. Or maybe the heater flapper. Wasn't hard to find...