After reading 10 pages of carb stuff, never found an answer, so here's the deal...

Acquired a '71 with a stock 2.0 4 transplant with 2 ltr heat exchangers with dual Weber 44 IDFs (Correction: 40 IDF 70s). The only non-stock pieces are a MSD and Bursch (besides the Webers). The compression is strong on all 4 and the Webers have the stock set-up/jetting. The Webers were rebuilt and tuned by a skilled mechanic who knows them inside and out but doesn't know the optimal jetting setup for 914s. The car has no start-up, idle, or general running issues, it just seems a little slow. The valves are in-spec and the car was recently tuned. I live about 300 ft above sea-level.

I don't track the car, but enjoy spirited back road driving and am looking for better throttle response, and all around performance. Any BTDT to share on an optimal set-up sizing?

vents
main
idle
air correctors

Muchos gracias

i think (but im no expert) people are going to ask about your cam... good luck

Thanks for the warning.

That makes two of us in the no expert dept. The cam is what ever came stock. The case has not been split as far as I know. (and I hope no one says that 2 ltrs came with different cams based on the year).

If you have a stock cam, then you may have some issues as I believe that the stock cam is for FI - not carbs... Webcam 86 or 86a

Brett

I also believe others will say that 44's are WAY to much for a stock 2.0 and will always be a problem to tune??

I ran 40's on a stock 1.8 (and now a 2056) and was very pleased. I also had headers and CFR muffler on the 1.8. I was really amazed that people dogged the 1.8 so bad because with that setup I could hang with any stock 2.0 till about the beginning of 4th gear...they had about 10 more mph on the top end.

Good Luck

while not optimal for your application, you can make them work better. do you know someoen with a wide band O2 meter?
how often do you drive it? are the plugs sooty black? are they coco brown? does it smell rich?

pull the jets and read the numbers? what size jets do you have now?
look down the bores with a flashlight. what size are the chokes?

I agree with finding a wide band O2 sensor. You should even consider bringing it to a local Dyno. Most Dyno shops have WB O2's and you can run the car under various loads. If you can get various jets and misc parts you can tune your carbs right there. usually $300 gets you at least half a day on the dyno. I've used Dyno's to tune EFI systems and it works great. It does not matter what cam you have as lond as the AF ratio is correct.

I am watching this thread to see what experience is posted.

I am building a 2056 with 44 x 38 valves and lightly ported 2.0 heads to match the larger valves.

I am contemplating various intake configurations webers (either 40 or 44) or 44mm redline weber TBs/EFI. The best bang for the buck is also a factor in the decision.

The cam setup is still being decided on, as is the compression.

OK. True confession time, I am a total moron when it comes to most things mechanical (other than changing oil, spark plugs, brake pads, and basic electrical). I just read the model from the actual carb - rather than what I was told, and it really is... a 40 IDF 70. Doh! The plugs are a mocha brown - not black.

I was going to have a mechanic change the jets, and whatevers if there is an optimum setting rather than stock on the carb. I don't know nuttin else - where the jets are located, or where to look for what - like I said total moron. Sorry but I was born missing the true mechanical gene. Hopefully I will not be tarred, feathered, and banned.

Dyno tuning would be cool if you guys can tell me what variety of parts I would need to show up with.

What are you comparing your current performance to?

You must have some sort of baseline. How does your current setup compare to a stock 2.0L with FI? Have you driven both lately?

Otherwise, you might be chasing a problem that does only exist in your head.

Oh it wouldn't be the last time I chased a problem only in my head.

My mechanic who works on mostly 911s, but has driven 914 2.0s with stock MFI says mine definitely lacks the snap found with the MFI set-up. My goal was to get as close to what ever that might be, but what I have now feels slow. But compared to what? My other car is a 73 911 with a massaged 2.7RS spec which has plenty of go (215 ponies). Now I know a 914 with a 2.0 with never approximate the kick of a 2.7 with an RS MFI, but there must be a bit more that can be achieved with proper jetting and dyno tuning.

If not, what are the alternative mods for under $2K?

I did find this on another thread since I now know the right Weber:

28mm vents
120 main
50 idle (use 55 if it cruises hot)
180 air correctors (200 made mine hot at extended high rpm)

Any thoughts?

I ran the following for years in my 76 2.0: Weber 40 IDF's, mild carb cam from Garretson (years ago!), mild porting, first with the original 76 exhaust and latter with 74 style SS heat exchangers with a Bursch quiet muffler.

Vents 28
Main 120
Air Corr 210
Idle 50
Emulsion F11

Not wild by any means, but very driveable with good low end pull. Good gas mileage too. Good luck.

........You have so many unknown varables that I recommend that you just allow your mechanic to make changes (jetting, timing,etc,) and you give him feedback...example..THERE is no certanity that the ventures, and jetting are as you assume unless pulled or visually checked.....If you have a "stock" camshaft, even with carburators, you will not have much of a performance gain over the original , OEM, performance of the engine...let an expert "tweek", adjust the carburators for you.