I have removed the FI. Now what?

[don hopkins]

I have removed the FI system from my 1976 914. I plan to install some type of carburetor. But which one and where should I get it from? I am considering the dual carb 44 IDF sold by Performance Products for $699. But this is rather costly. I plan to put a performance exhaust system on the car.

don hopkins
________________________
philly, pa
1981 911SC
1976 914

[Alfred1]

Kit Carlson has an aftermarket F/I system designed for the 914 that should be available pretty soon. Have you considedered buying that?

[AaronM]

The vast majority of the time, you lose both power and drivability when you replace the original FI with carbs. Unless there is something wrong with the FI system that you don't want to trouble-shoot or you're making a quasi-race or full-race engine you're almost always better off with the FI. A new exaust and a removal of the air-pump will bring that '76 right back to '73-'74 2.0 power output without changing the FI setup at all.

Aaron

[lapuwali]

Are you planning on doing more than just a performance exhaust? If not, then put the EFI back on. Fixing it will cost a good bit less than fitting a set of carbs.

If you are planning on more than just an exhaust (cam, larger displacement), then a complete setup with 40 or 44IDFs will work. 40s if you're not going too radical, 44s only if you're building a big motor or employing a really wild cam (race only engine). Since you're objecting to the $700 pricetag on a pair of carbs, I'm guessing you're not actually planning on going very wild, as this kind of work starts to cost a lot more than that. You'll also need to consider the price of an aftermarket centrifugal distributor (no vac advance). The newer Webers do have the provision for running vac advance, but you'll need to set them up for this. You'll need a few fuel pump, and really ought to have a fuel pressure regulator (Webers overflow if presented with more than 3-4psi of fuel pressure).

Besides the cost of the carbs themselves, there are other penalties. Fuel mileage drops, enough that 20-25mpg is common. None of the Weber kits available for the 914 have a cold-start or fast-idle circuit. Not a problem for a summer-only car, but if you're intending to use the car in colder weather, you'll find the car hard to start, with very poor cold drivability. All of the available carb kits also only come with individual gauge air filters, which mean there's a substantial increase in noise over a proper airbox. Carbs are much more sensitive to dirt in the fuel, and will routinely clog idle circuits if you haven't fully de-rusted your gas tank, replaced the fuel lines, and use good fuel filters.

For a daily driven near-stock car, the stock EFI is by far the better choice over carbs. Carbs are a reasonable choice for a built-up weekend toy. Aftermarket EFI is the best choice of all.

[don hopkins]

But it is not what I want. I put Webers on my 1981 911SC and the "fun factor" increased X100. With the "FI" I had to kick the pedal hard to get it to move. It was very unresponsive. With the Webers (40 IDA 3C) its like being telepathically connected to the engine. Touch the pedal and it responds.

[lapuwali]

Well, $700 for a complete Weber setup (filters, linkage, manifolds and carbs) is pretty much normal. Indeed, I wouldn't be a bit surprised if you called them and found the price has gone up since the dollar is tanking against the Euro. I've heard the price for a full system is as much as $1000 now. The actual carbs you'll get from any of the vendors will be the same. The rest of the parts will be different. CB Performance is supposed to have the best linkage. Aircooled.net appears to have the best after sale support.

If you're looking for responsiveness and you're not fitting a cam, stay with 40s, and use small-ish venturis (probably 28mm for a 1.8, and 30mm for a 2.0). Talk to the vendor about what's necessary to fit the vacuum advancer so you can stay with the stock distributor. If not, then be ready to pony up another $250 or so for a non-vac Mallory. Do NOT cheap out and use a Bosch 009 or you will be unhappy with the performance.

[pbanders]

The others are right. Without modifications, specifically, to the heads, cam, and exhaust, going from FI to carbs will produce LESS throttle response, LESS low-end torque, and the loss of fuel economy and increase in emissions. If you want carbs and you want it done right, consider going with one of Jake Raby's creations - not cheap, but definitely high-performance. If you don't have the money to spend, and want a car with good driveability, consider putting the FI back on and using my web pages to debug the problems.

[AaronM]

Originally posted by don hopkins
But it is not what I want. I put Webers on my 1981 911SC and the "fun factor" increased X100. With the "FI" I had to kick the pedal hard to get it to move. It was very unresponsive. With the Webers (40 IDA 3C) its like being telepathically connected to the engine. Touch the pedal and it responds.

Fix the loop-dee-doo catalytic converter piping (if your car is a CA car) and remove the air-pump and FI will give you more power and better response.

The 911SC has an entirely different engine from the 914.

I looked at a lot of 914's before I bought mine. The carbed cars were always the cars that had issues with drivability. The stock 914 cam does not like carbs. You have to really open up the engine to make carbs work. Otherwise you're just spending money for no gain.

Aaron

[lmcchesney]

As has been said, the 2.0L 914 engine was designed for the FI system. The stock cam has 16° overlap, split duration and 234° intake. This provides a vacuum signature that works with D-jet. The heads have restricted flowstock ports and valves with a CFM of about 110-120. Carbs allow for increased cam duration. P/P of heads and increased valves improve flow. Sooo, if you want to convert to carbs, the heads and cam will need changed to obtain tunned performance. If you are a DIY person, the specifics on parts and how it is done is on the web. However, Jake Raby produces a kit with the required items and instructions that has excellent reviews. If not a DIY person, there are several engine rebuilders which can build the engine.
And lastly, if you have decided to convert to carbs, sell you FI system to 65mech on this board:Another carb vs. F.I ques. It seems he is looking for a 2.0L D-jet.
Hope this helps.
L. McC