At some point, my motor (1974 2.0L) will need a rebuild. I'm not going to go the /6 conversion on this car. If I rebuild the motor to a 2056 or 2270 displacement, can I still use the FI system (D-jet)? Or is there some spot in here where it is better to switch to carbs? Or if I wanted to have FI then switching to L-Jet instead?

Happy to do some reading if you have it...

Rebuilding the engine to a 2056 with a Web73 or a Raby cam, rebuilt heads, flat top pistons and 8.5to1 CR gets you to 115-120hp using the Djet FI.
That's a pretty fast 914 over a stock barely 95hp!
A careful build with notched rods, everything balanced etc really helps and you still will get 25mpg if you keep you foot out of it.

and would only add that going to 2270, DJet wouldbe an exercise in frustration.

Add a 1 1/2" Tangerine EVO exhaust system to that and you'll get 130+hp.
Joe Sayre posted his dyno results last fall.

Any difference if it was L-Jet?

keeping the stroke the same and adding cylinder size, Either Djet will work up to about 2.4 liters.

I have heard rumors about Ljet going that far also, I have have no doubt it could given the right injectors and fuel pressure.

You cannot add stroke to Djet or it throws off the MPS too much.

You will need to adjust your MPS on a Dyno or street with an air fuel meter.

rich

Preface: I have no experience with L-Jet fuel injection.

I'm not an expert on the subject, but I am completely impressed with the stock D-jet. Yes, it has it's bugs and takes some time to figure out...but it is pretty darn good for 40 year old technology. A big problem was the availability of good MPS's...but Tangerine Racing took that out of the equation with their rebuild kits. I took a 1380 mile road trip in my stock D-jet 2.0 last fall, after my engine sat in the shed for three years - it performed well.

I will be paying attention to price drops on aftermarket & more modern fuel injection systems, but until then, I am sticking with D-Jet and don't plan on building an engine that won't run well without it at this time.

My advice...stick with FI...unless you need a fire-breathing monster.

It is certainly going to be a while before I tear down my 2.0L (fingers crossed) but my goal in this discussion was to see where the known limits are. Of course, I suppose this all depends on your goals for the motor. For me it would be:

Streetable motor
Longevity of the motor
Good power from lower RPM's all the way through
140-150 HP (or more )
Good gas mileage
????? Torque
901 Trans with better gearing
Upgraded brakes (BMW 320i brakes?)
D-Jet or L-Jet or Carbs?

I have recently gotten my arms around D-Jet operation as I got my 2.0L sorted out this last fall. It wasn't that hard really.

What is the consensus on CR for that set up?

From someone who has a 2056 with Djet FI

For kicks... I've got a 2056 with a JR cam and Ljet. I believe it was set up at 9:1. Runs real well after the first 60-90 seconds after a cold start, when it would like to stall without additional pedal. Feels like it has mucho mas cajones than the 2.0 I had...

I've driven Chris' 2270 with Ljet. Even more fun. I feel the Ljet is just a bit more "modern", and seems to be a bit more adaptable to a larger displacement engine.

these are simply my SOTP impressions...

That's my impression also about L-Jet....just a bit more modern. In addition, it seems to have way less number of sensors ($$$$). I'm not quite sure if the AFM is adjustable or not? Some old 280Z's I had could have their AFM box adjusted with a simple turn of a screw.

Very adjustable, and easy once you learn the principles of operation.

See Itinerant Air. Worked well for me.

I think Joe is referring to a stroker 2200 we built for Scarlet75. It puts out around 150hp.
In addition to that engine, we installed L-jet on another cammed 2.2L last year because the owner didn't like the dual carbs. He's very happy with it now.
There is quite a bit one can do with L-jet when the system is understood.
It does require quite a bit of tweaking though.
A wideband AFM is a necessity.

Yes, Chris, that's the baby! So sweet.

When you refer to a cammed 2.2, am I correct in that it was built for carbs?

Thanks

Don't mean to hijack the thread...but...

Is L-jet more adaptable to larger engines (with tuning of course).

Great discussion.

Yes, that engine was probably built with 44IDFs in mind.
We didn't build it so I don't have the exact details.

Either system can go as large as you want....

You are measuring air with either the AFM for volume, or MPS for pressure.

same technology used today, it's the only two ways modern cars measure air...
Pressure or volume.

You can tune and mps or an AFM to a certain point, and you can change your injectors and fuel pressure to make up the loss.

At that point, with all the tuning...you are still limited to what the camshaft is doing.
To much overlap will create flutter that affects both systems in different ways.

It can be overcome...just takes more tuning.

drag cars use manifold pressure
huge camshafts, lots of overlap.
Those cars run at WOT....so the mps is not in the way of the air flow and it's meaningless at WOT...

ford still uses manifold pressure for fuel injection in some cars.
Lots more use air volume measuring it with and AFM or other inline systems.

Rich

Maybe the best question is who has done the 2270 L-Jet setup and what did you use for components? What's the HP, Torque and power curve look like for said setup?

Look at the bird site. They have a write up where as some one built a 2.5 using I think a 2.0 injection. He achieved this by going to more efficient / larger injectors.

Thanks that was a good read. He went carbs though instead of fuel injection.

Anyone else build a big four (2270+) running L-Jet?

If you want to run FI with a big cam, go find the LH-Jet from a volvo. Use the injectors and intake runners from an L-Jet system, but use the Hot wire Mass air flow sensor from the LH-Jet volvo. You may have to fab a harness, but the hot wire mass airflow sensor won't be affected by the flutter problem you get with the vane air meter in the L-Jet system.

Interesting...now what years did these LH systems were used?
Thanks for the education.

You have to find an early LH Jet system. The later ones won't work. You also get a computer controlled idle system too.

Volvo and Saab. Early 80s.

I looked at using a system off a turbo volvo when I was considering turbo charging my 2270 and keeping fi. Exactly the same engine size as mine. I don't remember which model but they were a dime a dozen.

Gotta grab the ECU from the Volvo also right? or simply just the MAF and hook it up the the stock 2.0L ECU from an L-Jet (with fabbed harness)?

How about fuel pressure? Need to bump it a little?

You need everything from the LH-Jet car. The harness, the ECU, the AFM, the IAC, the O2 sensor.... EVERYTHING. Then alter the harness so you can put it on the type IV engine, and use the Type IV head temp sensor.

There's some great FI info to read about here on 914 World about applying CIS FI to larger displacement (and turbo) TIVs.

The L-jet would be cool because it is an "original" 914 FI system, and CIS is cool because it would look more like a 911

CIS suffers from the same problems as the stock L-Jet with high overlap cams. The air flow plate flutters in the reversion pulses, causing incorrect fuel mixture. The CIS 911 engines had a LOT milder cam profiles than the carbed or MFI engines to correct this.

Can you describe the characteristics of the motor once this was all said and done? Streetable? Where was the power band? Good idle on cold start? Idle on hot start?

TIA...

BMWs used Ljet as well. your 2.0 heads have 3 studs to attach the intake manifolds. stock Ljet manifolds have 4 so some adaptation would be required. going 2270 big? think carbs or aftermarket dual throttle bodies. bring a pile of c-notes and a bottle of aspirin.

You can use the 3 bolt intake runners with the L-Jet system. I have done it.

after drilling 4 new holes, yes?

No, I have put L-Jet injection on to a 2.0 motor using the factory parts. It is a complete bolt on with no modifications.

Drove that same car from Fort Worth to Salt Lake City for Parade 2012 in that configuration.

2 liter runners will connect to 1.8L plenums by using longer than stock hoses.

Yep, cool, thanks!

So Clay, if a hypothetical 2270 TIV was built with a mild cam focused on street driving and low-end torque (great for the weekend AX!) and designed around an FI system, and the build was by a novice hoping for low costs and easy assembly + tuning, would you go with L-jet or CIS??


PS: or D-jet with resistors, re-calibrated MPS etc??
PPS: I know the advantages of new, aftermarket FI options. Just inquiring about old "Porsche parts" retrofitting

I would use the L-Jet. It's already setup for the type IV, verses the CIS, which is not. You have to fabricate all the mounts and plumbing for the CIS system. The L-Jet is a bolt on.

The attached images show 2 liter heads, 912E runners and 1.8 L-jet plenum mounted for use. The only modification I did was reorient one of the runner tubes to better point at its plenum port. Longer than stock connection hoses are called for (probably sourced from McMaster-Carr).

I just used some radiator hose from FLAPS and some hose clamps.

But then I am cheap that way.

Anyone know if the chip in the stock 914 ecu is soldered in?

Anyone had a look at the content on the chip?

Shouldn't be that hard to change the fuel table...I have mapped VW Digifant earlier, and the 914 ecu cant be any harder?

Chip ?!?! This is a late '60 design, it's all analog.

The 914 fuel injection box is not really a computer. The D-Jet is a bunch of 1960s era big assed transistors. The L-Jet is a little more refined, but there is no real "processor" and there is no such thing as a programmed fuel map. It has a bunch of transistors, resistors, and capacitors that control the fuel map. Changing the fuel map involves replacing resistors to change the mixture curve.

Welcome to the 1970s.

Yep.....transistors...no integrated chip in there.

Hello World -

I hope you don't mind me bringing up an old tread. I'm interested in the conventional wisdom of how far the D-jet can stretch to larger T4 builds.

I saw these youtube videos and it got me wondering if D-jet would work up to larger displacement T4 engines say up to 2270. These videos say 2.4L but I wanted to know what the experience here is.

Porsche 914, 2.4 with Bosch D-jetronic - It lives!

Porsche 914 2.4 with D-jetronic

The other relevant 914World thread I found was...
What is the largest displacement engine - FI

It seems the 2056 with D-jet is very typical.
Can the D-jet be made to work with the 2270? What modifications would be needed?

Know that I am a ways off from getting this sorted. Just dropped the engine yesterday - thanks Ian - and have some serious body repairs to make before getting to the motor. I certainly don't want a built motor sitting around with nothing to put it in. As I stated at the onset, would like to hear the current consensus about the D-jet on the bigger 4's as I have some time to ponder FI vs Carbs as I work to put this body back together.

Since we all love pictures...

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Thanks in advance.
Sean

The 2056 with Djet is the best of both worlds as that's why most go with it. It can be in the 110 to 125hp range with the right combo of cam and heads. Its easy to build and runs cool.
The bigger 2270 means more work on everything to get it to run right and cool. Anywhere from 150-175hp...

My question to you is how big do you think you need to go as 125hp is alot in these little cars. Especially if you haven't addressed the suspension, brakes, rust etc.....

Even D-jet on a totally stock car can be frustrating these days with the age of the system and the lack of parts. I used to be a d-jet purest but dealing with that system has become much, much more difficult and more expensive over the years.

If "upgrade" is your ultimate goal I would forget about d-jet, at least all the electronic pieces of it (the actual intake, throttle body, etc work great with a Megasquirt setup) even if you get d-jet working "well" you are still going to be limited in what you can do with it engine wise.

Ditch the d-jet and go modern injection and a 2056 properly built to take advantage of it is looking more like 140hp + much nicer manners.

https://www.youtube.com/watch?v=gINH-EDVKdM

https://www.youtube.com/watch?v=xtsmebEX25k

If you want a stock looking FI system, but have some money to spend, think about this:

Take a D-Jet system, and replace the insides of the "computer" with an MS3-Pro module. Replace the trigger points with a trigger wheel, the injectors with more modern ones, hide a modern TPS inside the D-Jet throttle switch and hide a modern MAP sensor inside the MPS. Lastly, gut the aux air regulator and put in a IAC. Optionally, use a wide band O2 sensor to run the auto-tune, and fire the coil from the ECU.

Fully programmable FI, and it would look dead stock. And it would work with any displacement motor you could bolt it onto.

Just some thoughts. I've recently been tuning my 2056cc with D-Jet. I was running rich and with an AFR meter I discovered I was running about 10:1 AFR across the entire throttle range. I have since leaned it out.

I've seen people say D-Jet was used on up to 2.4L engines and with how rich I was able to get the mixture, I'd imagine you could actually get it to work with a 2270 engine. As others have said, it will take more to keep that larger engine cooler.

Thanks for the replies. Let me add some input for the questions so far.

The motor pulled from the car is a 2.0L with Italian Weber 44s on it. It ran. Just not well. However, I didn’t drive it much due to the (unsafe) rust issues. Which means I have a set of 44’s that I could use (if rebuildable) on a 2270 and I am told are too big to get tuned well for 2056 let alone the engine coming out of the car.

I also have a full D-jet system for a ’74 and most of the makings for a second D-jet system also for a ‘74. One FI harness is a core for sure and the other is known to be working but should be replaced for reliability because of its age.

A stock set up isn’t my concern. In some sense having the right package is. I want the injection system to work well for the engine configuration. Just trying to size up what that might be which has led me to this thread and my questioning the D-jet capabilities. I very much appreciate the feedback thus far. 140 hp with a modern FI system on a 2056 is a very good argument. However, by the time I get through the body there may not be additional funds to lay into a modern FI system.

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If you wanna step up the performance

Djet isnt your friend.

You have to decide between the daily type driving ( djet)
Or balls to the fire wall Aryton Senna style driving
( carbs)

There is no life in between