924Board.org

[bryanc]

I have seen it applied enough times to realize there is a reason people are going to carbs but I'm not sure I understand it. Is CIS less of a fuel delivery system than carbs. I know side draft carbs have been around a long time and a lot of cars use them (english, 240Zs and others) but what is the advantage of going to them on 924s? Is it just airflow? Couldn't you just get a higher volume FI system.
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'84 944
I'd rather have a bottle in front a' me than a frontal lobotomy
Tom Waits

[Roger]

CIS is an old system, and old fuel injection systems can be tricky. I was told that CIS was originaly designed for Jaguar. It was a good solution durring its time. I belive that most people resort to carbs because its eaiser than installing EFI. EFI requires creating new maps and having them put on an EPROM. This is very specailized and usually requires several tries to get it correct. Some people have installed Delco EFI systems.
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1981 924 NA

Some people are like Slinkies. Not really good for anything, but you
still can't help but smile when you see one tumble down the stairs.

[HappyPuppy]

Carbs are easy, plain and simple--easy to fix, easy to install, and easy to tweak. If I had $900+, I would switch to quad TBs, quad MAPs, and 2 injectors per, but I don't, and I'm still happy with my DelOrtos that came with my 924.

Just my 2 centz...
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My frequent desire to perform violent acts on select other drivers is not road rage; it is simply preemptory self-defense.

[Richard]

I think people go to carbs because there is a proven perfromance gain over the old Bosch CIS. This does not mean they are getting good fuel mileage or can pass emissions test. I re-read an article recently about hop up tricks for the 924 and the author's assumption was the air door in our mechanical fuel injection was only really good for about 125 HP in a normally aspirated engine. And then some people also like the sound of carbs.

Electronic fuel injection is really the more sophisticated way to go (in my opinion). I am going to be building from a kit called Megasquirt. Another source is www.euro-audi-parts.com/Eurobits034efi.html You can also buy all the works from a wreck with similiar engine size and horsepower and just stick it in and see what happens. Chances are though perfromance will not be optimum. Try doing a search for aftermarket electronic fuel injection. Or call Paceo and get some carbs. Or just learn to love your quirky CIS.


s

[wdb]

yeah , its hard to beat the 2hours of labor and $20.oo price to completely rebuild a carb. with the FI you have to FIND the problem , injectors ,there ports for leaks, almost 2 meters of ductwork for leaks , pressure reg, fuel pump ,metering adjustment , fuel/air ratio , fuel distr. o2 sensor, wires , pump relay ,aux. air regulator, decel valve ,fuel distr. head.and then half of the time its not 1 problem, its everthing is just slightly off or needs cleaning and tightening , so when you check them all, they look ok individually,and your still not sure whats wrong .and all these parts are exspensive to replace when they fail . the more parts a system has , the more likely it is to break down . a carb only has 4-5 moving parts , throttle plate and actuator , choke , the float assembly, accel valve(squirter) ,and on auto trans the kick down linkage . you can buy a holly 2 brl carb for $20-$40 on ebay (new $250), but there is no manifold available to mount an upright carb to the engine that will clear the hood . you would have to have the stock 924 manifold modified , and that would probably cost $100-$200 dollars . the webers that are available for the 924 , come with a manifold but the whole setup is prolly around $550-6

I forgot about the low pressure fuel pump needed to run carbs ,I dont know what they cost guess around $50-$75

http://www.redlineweber.com/html/Aplication_guide/PORSCHE.htm

[Peter_in_AU]

it's a religious thing

Carbs are simple and need to be tuned once a day except in winter when they need to be tuned twice a day. They are efficient over a very narrow power-band, leak and look and sound great.

EFI is complex and never needs to be tuned and delivers fuel accurately over the entire engine rev/power range. Boring!

CIS (our system) is an amazing system. It's amazing that it works at all, it's amazing that it works so well and it's amazing that it works so well after 20 years. The main problem with CIS it that very few people can get their head around it (I can't). It's a bit like the workings of the Egyptian tomb in the Indiana Jones movies, you know, where you blow out the candle and the 400 ton door automatically opens.
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1979 924 (Gone to a better place)
1974 Lotus 7 S4 "Big Valve" Twin-cam (waiting)
1982 924 (As featured on Wikipedia)

Learn to love your multimeter and may the search be with you