Cross-Fire Injection...why is it bad?

[Stallion]

I was just reading that in the '82 Vette, Chevy experimented with cross-fire injection, and then Newton said that this is a reason not to get an '82. Why is this? What problems arose with cross-fire injection? Repair/maintainance difficulties with it? What?

Thanks!

 

[DkBG]

I had the CFI on my 84 . It was the only part of the car that never gave me any trouble .

 

[Stallion]

Then why do people complain about it?

 

[Laserred91]

Most people just talk smack cuz they heard somebody else doing it... Ignorance is bliss!!! Most of the people who complain about them havent even owned one.
Its a very reliable system,making only 15hp less then TPI in stock form. Very capable of making 300hp with a good cam swap,ported manifold,and some good exhaust,etc.

If you really want to learn more about it check out : The Crossfire Injection Vault Read up thiers a ton a good info here. Chris

 

[Stallion]

Alright, I see what you mean. I don't think it would turn me off of buying an '82. I would still love one!

Thanks!

TR

 

[MoeJr]

I own an 84 now and I love the CFI. Mine runs strong and is as responsive as any other Fuel Injected vehicle I seen. My 84 is bone stock with 80K and will chirp 2nd at 1/2 throttle. I much rather have this than TPI. CFI has less sensors and is actually not that hard to tune in terms of syncing the Throttle Bodies. Again don't let them dissuade you. A CFI vette is a great ride. Remember an 84 C4 is still one of the top handling Vettes ever made. .95G's on the skd pad with the Z51 Suspension(which mine has). They ride like a brick but corner like they are on rails. Just my .02


:bar

 

[geekinavette]

I think that there are two reasons people "complain" about the crossfire:

1) they simply don't understand how it works
2) the intake runners are pretty darn small compared to a typical SBC intake.

Unfortunately the first item above holds true for most dealerships as well as do-it-yourselfers. You either have to be willing to learn the system and how to troubleshoot/repair it yourself, or make sure you know a good mechanic that knows the crossfire system. If you fall under the DIY category, then the CFI Vault that Chris mentioned is THE place for crossfire info. Between that site and the knowledge here at CAC there's NOTHING that can't be answered relating to crossfire.

As for the second item, while true that the smaller runners will decrease the high-RPM performance, at the same time it produces some pretty good torque at lower RPM (pretty close to 300ft lbs as I remember). So is crossfire a good system for racing....not in it's stock form no. Is it good for street driving...you bet!

Whether it's a monster big-block or a whimpy small-block...a Vette is a Vette. If you like it, that's what matters in the end!

Just my $.02

Bill

 

[JHL]

There is nothing basically wrong with throttle body injection, it was used on a lot of European and Japanese cars when fuel injection started to take off. It is not the most efficient method of delivering fuel but better than a carb as the mixture is controlled by a computer hence it should be the right air/fuel setting for any circumstances. The GM Camaro/Vette set up did have it`s limitations but this was mostly to do with the intake manifold rather than fuel delivery and things have moved on since but if it is working properly it is ok. Most of todays systems are multipoint delivering fuel almost directly onto each of the intake valves with the manifold delivering the required amount of air. Fuel is matched to airflow by some form of sensor in the intake which then relays this info to the computer and the right amount of fuel is injected to match the volume of air

Some cars now have direct injection which is similar to a diesel in that it injects fuel straight into the cylinder with the intake valve only letting air into the cylinder. These systems run at extremely high pressure to spray the fuel in a very fine "mist" to make the most of the combustion process.

I had a Z28 with CFI and it ran faultlessly in all the time I owned it.

J.

 

[sscam69]

Some cars now have direct injection which is similar to a diesel in that it injects fuel straight into the cylinder with the intake valve only letting air into the cylinder. These systems run at extremely high pressure to spray the fuel in a very fine "mist" to make the most of the combustion process.

My thesis was going to be based on how to design and build an "Optically Accesed Direct Fuel Injection Spark Ignition Engine" BUT I have grown tired of school and I am going to get my professional career going.

The problem with a DISI engine is the emissions as a result of the fuel hitting the walls and piston in liquid form. It produces a lot of hydrocarbons. Bad Bad Bad......:nono

 

[Stallion]

When did Vettes stop using carb engines? And then there was the CFI. Where does this TBI come in? How does that system work?

Thanks!

 

[TONY TAT2]

On the throttle bodies of the crossfire just think of them as a carb,but instead of jets thay have a injector for better atomazation of the fuel,,,btw the only C3 vette i came across SO FAR was a 76 in philly for $8k but it needed a motor,,,still looking 4 ya

 

[cruzer99]

Most people who bad mouth the TBI are just jealous.......Just kidding....:L :L :L :L :L

I'v had two 82's and never had a problem.....there are GREAT

 

[geekinavette]

When did Vettes stop using carb engines? And then there was the CFI. Where does this TBI come in? How does that system work?

Thanks!

'81 was the last carb'd vette. '82 and '84 were the only years for crossfire/TBI. After that came TPI...etc. The crossfire system uses two TBIs mounted somewhat "diagonally" on the intake and each TBI "feeds" the opposite side of the engine, hence the name "Cross-Fire". It's very similar to the old Z28 302 Cross-Ram, but with throttle-body injectors (TBI) instead of carbs, and much smaller intake runners.

Bill

 

[Stallion]

I'm not sure I understand how the fuel is dispatched in the cylinders. In carb engines, there's just one carb, right? And it supplies the mixture in the heads so the intake valvles open up for it? Is that how that works?

But in CFI there are two injection mechanisms? Is that how that is?

Thanks!

TR

 

[page62]

Two throttle-body injectors is what makes CFI kinda unique...

 

[JHL]

sscam69

I am surprised at your comments Direct Injection petrol cars are currently available in the UK from Mitsubushi for one, they meet all current European emission regs and give near diesel fuel economy, as legislation has tightened in Europe most manufactures no longer make cars specifically for the North American market, as they used to do previously, and a lower spec for their remaining sales. Most now have engines that will meet the requirements of a growing global market.

J.