So how big ahve you seen or heard of a 2.0 liter type 4 with a tweeks stock FI setup???

I need to know specs, I know 2056 works, I feel that it could go bigger, I am thinking 2.2 possibly, with a higher CR and a web cam, ported/polished heads.

I would like to hear Jakes real world trials to see how far he has gone, I know he has tried big displacement with the stock FI, I just want to know where the line is??

On that topic, how about 2.4 liter using the 4.8 liter mercedes injectors (they fit and have the same voltage requirements, and an old porsche race team mechanic said he had done it before)

Any thoughts?

Rich

The D-Jet gods seem to all hover around 2.3L as the upside limit to the stock 2.0L 914 FI system. Requires tweeking the MPS, maybe boring out the TB and increasing fuel pressure. There is a lot of untapped power in the 2.0L injectors.

any real world examples?? the above work sounds easy enough? just really curious as to the cam and what you would really gain without a more agressive cam....

Rich

New d-jet parts are very expensive so unless your d-jet is working perfectly it might make more financial sense to get an aftermarket system.

I can tell you the cam makes a world of difference, even a fairly mild cam like mine (Webcam 494).
Mine is carb'd but a properly adjusted FI system should be able to take advantage of the cam.

Go aftermarket for tweekability!

Yes, but the D-jet ECU is really the problem. Iit is configured for certain parameters with a hardwired (resistors) fuel map in it.

To really tap any potential with air flow increases, cam changes, exhaust, headwork, etc., you need MORE flexibility than the stock D-jet ECU Can provide.

I like the idea of maybe using e Megasquirt or the KitCarlson product with the Rennline throttle bodies or creating a whole new intake system.

I'm really surprised that to this day noone has gone into the ECU itself and changed the operating parameters inside to work with non stock configurations.

We have the technology...

I like the redline stuff...

...roller motor, nikasil... ect.. cool.



M

Its been done to some extent, but really modern EFI is the way to go. I have heard a 2.4l is about the limit of the 2.0l set up if you keep the same VE curve. Different cams with valve overlap will kill the idle with a manifold pressure type FI. Some MPS's seem to be able to provide more range for fuel adjustment than others.
With dyno work or a nice wideband you should be able to run 2.4l with a Web 73 cam. So whats that hp wise, hmm maybe in to the 130 range??

Or just a 2270 that is running the Webcam 73.

If I had the time I would pursue this just for shits and giggles.... maybe next year..

Geoff

actually, we don't.

the DJet is 40-year-old ANALOG technology. the essence of the system is the way the MPS uses a variable-core transformer to shape the pulses created by the trigger points. everything else is band-aid circuitry to 'tweak' that -- cold-start, full-throttle enrichment, warmup...

when you go in and start replacing bits of the analog stuff with something you can actually get parts for, digital stuff, to replace different elements of the pulse-forming and pulse-shaping modules - you will find that you have re-engineered the MegaSquirt (or one of its ilk).

something to bear in mind. my understanding is with a 2270 you need to run headers and and a oil cooler other than stock. tom perso has one in his and said that it ran pretty hot with the stock cooler. the price starts to climb rapidly with the add ons. with the engine cost and the other upgrades, the rational for a 3.2 starts to make sense.

kevin

Finally, you are coming around to the real world. A 2270 engine is nice but for the money if you look at all exspenses the 3.2L is the best bang for the buck.


Geoff

I have tried SEVERAL combos with theD Jet. One engine I tried 4 cams in before giving up.

Trust me, unless you want a huge risk on your hands, go no bigger than a 2056 (and even then they sometimes melt because of it too) and cross your fingers.

The stock FI is my LEAST favorite thing about a TIV engine, and its getting worse, the older it gets.

The 2270 is the best engine for the money, no doubt.......when the 3.2 breaks, or needs a tune up, watch out...........When a set of sparkplug wires cost 200+ bucks, I don't see that being a smarrt move...... set of cylinders cost 4K PLUS, well........

They might last a long time, but when it breaks, bend over!

Thats true of any motor Jake. I well cared for 3.2L should go for 250k miles with a top end refreshing at 150k.
To get that same quality you have to build the 2270 with Nickies and those aren't cheap either.
I realize that you have reinvented the wheel with the 2270 but I follow the saying "Keep it simple stupid". I'll go for the six..
I do have a 2056 now that I don't have any problems with. I did adjust the MPS on a dyno to correct the A/F. Oil temps run in the 200 degree range. Dyno'd it a 95hp at the rear wheels so it aint stock.

Geoff

I have several 2270s on the road without Nickies that have over 100K on them. The sparkplug wires cost 40 bucks for a SUPER set.......

One customer put a 2270C in his 72 914 in 1997, he spent 5K on it then. The engine lasted 115K before he went through it....The complete tear down and refresh cost him 2300.00 and he even sent it back to me to do it.

The second time around the engine made 155 BHP on my dyno. So for 7,300.00 and a few bucks in shipping the engine has went a total of 150 something K now(as oflast time he emailed me)

Do the math....and he DOES NOT have nickies, ceramic lifters or any of the trick goodies......matter of fact that was the 3rd or 4th 2270 I installed into a 914.........

The customer does not get on the net, to do forums and etc but I'll see if he will write me a bit to post here for you guys......

My humble opinion:

I wouldn't go bigger than a stock with a D-jet. The Djet is measuring the manifold pressure and making a hardwired guess about how much air that means about how much fuel to put in. A bigger engine is going to have more suck, so I'm not sure it would compensate correctly for a bigger engine.

The L-jet might be able to take it because it is measuring the weight of the air going into the manifold, however the L-jet seems to be less, not more popular with 914 folks.

If you want to FI with a big-4 I would use the D-jet manifold, and injectors, bore stuff out a bit and run a megasquirt. It's not too hard to set up and if you can get access to a dyno, or a wideband O2, you ought to be able to do better on performance than the carb guys with the same engine.

As for injector sizing - there are calulators out there that will help you figure it out. The link below should help - just set the turbo boost to 0psi and the Intercooler efficiency to 0, run at about 75% volumetric efficiency at the redline rpm. Fill out all the other fields, for bore and stroke etc, and it should give you an injector flow rate. The Meqasquirt FAQ has a table of different injectors, so that should help you source them.

http://not2fast.wryday.com/turbo/glossary/...urbo_calc.shtml

I believe the 2.0L injectors are a little oversized so they might work fine. I have also heard of people using Subaru injectors. I think you'd be pushed to get an injector that is too big - as long as you can psysically fit it, and it's from a vaguely similar setup. Basically - the bigger the injector, the less granularity you have over how much fuel is going in. The fuel amount is varied by opening the injector for shorter or longer times, and most systems only work to a certain timescale. There is a high-resolution version of the megasquirt software that you could go to if this is a problem, but it won't be if you pick injectors that aren't way oversize.

Fiid.

ok,
lets just say for a moment that the DJet can handle a 2.4, or even a 2270
Why would the engine be getting hot, is it running to lean?

Rich

If you could pick an "Off the shelf" cam, Webcam, or the likes, for a big four, that you could use with an aftermarket FI system like the Megasquirt or the KitCarlson project... what would you use and why...

I am not an expert in mixture stuff by any means. I got a Wideband O2 sensor so that I don't have to be :-)

I am pretty sure that running lean causes extra heat. It can also cause burnt valves. Turbo engines running lean can cause catastrophic results. Beasically - I think if ytou are running lean you get an explosion instead of a controlled burn. This can also burn your valves I think.

Running rich doesn't seem to do all that much, but it does cool things down, and causes some build-ups that are bad.

Lean also puts out more power from what I understand.

Our engines are supposed to run slightly rich of ideal (stochiometric point) which I believe is 14.7:1 Air to fuel. I think we are supposed to run at about 12:1 or so.

l8r,

Fiid.

I don't think that the MS is limited by firing times like the D-jet is, so it will squirt into whatever cam you want. You might have to tune it differently to compensate for crossover if you are doing that - again - not an expert, but out ought to be able to go as hot as you like.

Fiid.

Our engines are set up to run at 13.7 to 1 at part load and 12.8 to 1 at WOT.

How did you arrive at those numbers - by testing OE pressure sensors? This is all I know:

Its in the Bosch and Porsche manuals, if you want the exact page I would have to look it up.
14.7 to 1 is too lean for a air cooled engine.

Geoff

The manuals that can be downloaded from this site? Yeah, if you get a chance, please let me know the page numbers or scan and post the pages. That way, I'll know exactly what to shoot for when tuning my carbs or aftermarket efi.