I'm pretty sure the previous owner (PO) just put a pair of Weber 40 IDF's, a 009 dizzy, and a fuel pump on and kept the stock cam.

How does that make things work? Should the cam be changed?

Yes it should, BUT you can still have drivability with the FI cam. You won't be at the peak performance though. Changing the cam is a complete rebuild.

The 009 should be the first thing to toss. Get yourself a Pertronix SVDA or drop the money for a 123. It is night and day once you put anything other than the 009 on it.

Another vote for the 123. It is worth it. And dont tell George.

There are a TON of 914s driving around with carbs on the stock cam. Its a LOT of work to change the cam. I'm guessing a bunch of 2056 and 1911 cars are also driving around on a semi-worn out stock FI cam.

Changing the cam is a full engine teardown. You can't change it without splitting the case.

The cam really wakes up the engine. The FI cam is made for a easy idle, steady vacuum signal. Bigger cams can change your powerband, react well with more compression. But - they can have a less even idle and vacuum signal so EFI does not like them. Carbs care about neither of those. So with carb conversions a cam was a way to give a small motor a little more zip.

The usual HP numbers for a 1911 and 2056 (110hp and 115hp) assume a stock cam. Cam choice can bring those up.

Zach

Now I'm going to take this conversation into the realm of the stupid.

If you have a carb cam and want to run a modern EFI. Can you tweak the tune to accommodate the carb cam?

Thanks.

George

Yes. See link in my sig (it's "TL;DR")

@GregAmy

Wow. Thank you. I'm going to read this several times and follow your lead.

I have two 1.7 cases an EA and a W0. I'm not sure what I'm going to do but I am considering building the EA to be a 2056 carbureted engine and the W0 to be a 2270 EFI engine.

FYI. LN Engineering / Type 4 Store has a few cam kits on sale now for 20% off should you need.

Any modern programmable EFI will accommodate a radical cam profile that would never work with the stock D-Jet or L-Jet. The system can be programmed to deliver a smooth, stable idle and all the power available from the engine.

look at Elgin camshafts, Webcam, and follow along with what others have done with more aggressive camshafts.

consider that EFI measures the air in some way.
If you have a high overlap camshaft (great for performance) you need to be able to adjust your EFI to overcome, or just make sense of, what could be, a large bumpy fluxuation of air that you are trying to measure.

Go watch a video of a real dragster....listen to the idle.
Its literally on/off at idle
That is a super aggressive camshaft designed to run at 10k rpms.
The stock 914 camshaft for Djet/ljet is on the absolute opposite end of the scale, and its designed for emmissions, and a very calm idle.

Stock EFI in these cars has a fixed set of A/F maps that are used.
Its all a compromise...not tunable, cannot really run well if the input it changed (a different camshaft, different Air pulse)
The stock Djet system is capable of 150 HP at the wheels, with a larger motor.
BUT....you are tuning the MPS and CHT to do this.
nice part is you can use a camshaft from Elgin that is darn close to original...so idle is not too bad.

Go to carbs...or tunable EFI, and you can now start doing much more with the camshaft.

Remember....the drag car at idle.
Its the direction you are going with higher lift and more overlap at the camshaft....
So...you need to really focus on idle and 0-30 MPH....those are the key places to make it run well, and design for it.
Once you are over 3500 rpms...things are moving so fast that the A/F lumpy pulse goes away...and you are in race car camshaft territory..where they shine.

Decide what you want to do with the car.
Design for that use case...not the drag car.

Rich

Exactly!

My 2056 running Microsquirt (that was state of the art for 10 years ago) was able to tame down a carb only cam no problem. Cam profile really is not an issue for modern EFI.

Zach