Type IV upgrades and FI, Where's the cut-off to carbs? Options

[boxsterfan]

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... (IMG:style_emoticons/default/chowtime.gif)

[Bleyseng]

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.

[ConeDodger]

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.

(IMG:style_emoticons/default/agree.gif) and would only add that going to 2270, DJet wouldbe an exercise in frustration.

[ChrisFoley]

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.

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. (IMG:style_emoticons/default/smoke.gif)

[boxsterfan]

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.

(IMG:style_emoticons/default/agree.gif) and would only add that going to 2270, DJet wouldbe an exercise in frustration.

Any difference if it was L-Jet?

[r_towle]

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

[saigon71]

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. (IMG:style_emoticons/default/aktion035.gif)

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.

[boxsterfan]

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. (IMG:style_emoticons/default/aktion035.gif)

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 (IMG:style_emoticons/default/smile.gif) )
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.

[914_teener]

What is the consensus on CR for that set up?

From someone who has a 2056 with Djet FI

[Porschef]

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...

[boxsterfan]

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.

[Porschef]

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

See Itinerant Air. Worked well for me.

[ChrisFoley]

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.

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.

[Porschef]

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

[saigon71]

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

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

Great discussion. (IMG:style_emoticons/default/beerchug.gif)

[ChrisFoley]

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

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

[r_towle]

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

[boxsterfan]

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?

[0396]

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.

[boxsterfan]

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?