cb performance fuel injection

[mikey]

Anybody had any experience with this fuel injection?? Comes in either 40mm or 48mm dual throttle bodies. Does this system have temp sensors, throttle position swith, etc?? What is the overall performance of these??

Thanks,
Mike

[roadtrp204]

CB Performance's CFI 'competition fuel injection' is a simple open loop system, it ran me about $1700. They ask for the type of car, size of engine, and what range of cam to set the type of injectors. Mine came with 48mm throttle bodies, and if I did the math correct it would be the equivalent of a single 96mm throttle bore on the stock FI (maybe a bit excessive). The kit is fairly simple, just slightly more involved than putting on a set of dual carbs. There is a temp sensor, throttle position sensor, and the mixture is set on the fly by two control knobs that go inside the car. It is a digital FI made with GM components, even has a diagnostic port which can be hooked up to a diagnostic machine as if it where a GM vehicle. Sorry no details on performance yet, I have to finish up some suspension and chassis work before I put the engine in. I believe it will run strong though.
Chris

[bowlsby]

2 cross sectional area circles of 48mm diameter is not a circle of 96mm!

You'd have to do the math to find the area of the 48mm circle x 2 and then solve for the resultant diameter of the new circle.

[mejulihn]

If my math is correct, the area of two 48mm openings is 3617.28 sq. mm. The area of a single 96mm opening is 7234.56 sq. mm.

[Dave at Pelican Parts]

Remember, the setup we're talking about here is a single one-throttle setup, versus a PAIR of dual-throttle setups. One throat versus four, total. Since the area is proportional to the square of the diameter, to get four times the area you need to double the diameter.

So four 48mm throttle bodies have the same area as a single 96mm TB.

--DD

[John Rogers]

Dave is correct, the FI system has 4 throttle bodies of 48mm and it equals one big 96mm (that's why he won the tech quiz....). But the four throttles will give MUCH better response than one big throttle since each cylinder has it's own intake system and there is no central plenum.

[mejulihn]

Actually Roadtrp204 never said how many 48mm throttle bodies he was using. Four is the correct number as John points out, making Roadtrp204's calcs correct.

[mikey]

......so......anyhow......how does this system perform??? Anyone try it yet. At around $1700, it should make you pop wheelies.

[Dave at Pelican Parts]

Mike Nugent used the CB stuff on his Big Four.

http://www.pelicanparts.com/techarticles/914_big_four/914_big_four.htm

http://home1.gte.net/nugentmd/914litedetails.htm

--DD

[John Rogers]

For that price you could buy two sets of Weber 48's and some extra jets, etc. But you would have to adjust them for altitude, temp, etc but with a FI system you can make electronic adjustments..... But you can pull a Weber and rebuild it in less than an hour and be racing again. I have also found a FI system likes to be run more than once a week or two like with a race car since our wonderful CA gas will goop things up. But the bottom line is a good FI system will make more power and will probably be smoother too.

[Germain]

This may sound weird, but has anyone tried installing the K-Jet F.I. system on one of these? With the aid of the Mass airflow sensor installing a solid turbo or supercharger unit would be a breeze.

[Dave at Pelican Parts]

The CIS (K-jet) has been done. With a turbo, even. http://members.rennlist.com/evill

There is a page around somewhere that has details of the turbo install as well, but I can't find it.

Also, K-jet uses an air flow meter, not an air-mass sensor. The meter is mechanical in nature (a plate which is lifted by the air) and is mechanically coupled to the fuel meter. In the basic K-jet setup, there is no electronics at all.

--DD

[roadtrp204]

Oopps, guess I forgot that detail. The throttle bodies look just like Weber IDF's and even use the same manifolds, linkage, air clears, and velocity stacks. The price I quoted is for the entire kit, includes everything from fuel pump to air cleaners. The throttle bodies can be purchased seperately, and I am sure there is a few electronic FI wiz's out there who could make their own system for much less. I checked out other options and decided that this was the cleanest setup for me. When I purchased my car it came with a progressive two barrel, I then tried two singles, and then a set of dual 40 Webers. I thought my Webers were great, but the FI will offer better throttle response and a much easier and adjustable means of controlling the fuel mixture. With aid of a fuel mixture gauge, I can use the street or track for fine tunning instead of a chassis dyno.
Chris