I have a -71 camaro and am currently running a mildly tuned 355 and a muncie m20 4-spd gearbox.

I have been thinking about replacing my performer rpm intake and holley 600 carb with fuel injection and can get hold of a complete 350Tbi system from an -89 van.

Does anyone know if this fuel injection can match my current carb/intake setup regarding torque/Hp? Will the system fit my engine or is there any differences between the 350 from 89 and mine from 71 that will make it impossible to mount the system?

What do I have to do to reach 350-400 Hp with this kind of fuel injection?

[This message has been edited by Attenator (edited July 04, 2005).]

depends on your heads

you'll probably hafta do some intake modification because if i'm correct, the mounting for intakes changed in 86. so you'll probably have to grind out your mount holes to fit angled bolts. won't hurt the sealing properties if done correctly though.

all in all, performance wise, i don't think it'll help/hurt enough to really be worth the trouble.

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Click here, it'll explain it all (http://img.photobucket.com/albums/v628/luda79/sig.jpg)

luda is right on the manifold. It will have to be modified but it's minor and can be done. I think the driveability will be improved. For specifics try http://www.jimsperformance.com/index.html and be sure to download ULTM8Z's EFI guide. These two sources were extremely helpful in my TPI swap.

This guy sells machined manifolds and throttle bodies, http://xtremefi.com/
He may be able to help you on the manifold. His work looked and worked great for me.



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Dave

Sometimes your the windshield, sometimes your the bug.

[This message has been edited by Mstrtch (edited July 04, 2005).]

carb > tbi

dont waste your money on it. you might get slightly better gas mileage but thats it. most guys on the third generation boards that have it cant wait to get rid of tbi.

tbi is perfectly legit for building more power, just like any other induction system.
tbi was set up super weak from teh factory and earned a pretty bad rep as a result.
it will give you easier starts, better mileage, can work with any common carb parts, and is easily tuned at home.
only thing you have to do is tune it to your application, just like any other fuel injection swap. if you don't tune it, it won't perform very well.
i ran tbi and moderated teh tbi forum on thirdgen.org for a long time. if you have any questions shoot me an email or hit me on AIM, njspder

later
tim

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NJSPEEDER
1976 Camaro LT
New Jersey F-Body Owners Association (http://www.njfboa.org)
www.njfboa.org (http://www.njfboa.org)

Should look into how many CFM those TBI units flow. I dunno how much, but some of the factory units were pretty low.
I think it would be a good mod if you ave the time to put in it. I agree that the main gains will be in cold starts and driveability. Don't expect much gain in power from a well-tuned carb of the same CFM. Mileage might be a bit improved, but not tremendously.

Re-arranging the intake to fit a throttle body is not a requirement- there are plenty of carb. intake to throttle body adapter plates out there- yes they add some height to the whole setup- and hopefully you have the space to accomodate this.

As Blueyes mentioned- most stock throttle bodies (i.e. for a 305 or 350 engine) don't flow alot of fuel- so going to a 454ci-intended unit or ordering an aftermarket one may be necessary depending on your output level.

I think the biggest problem is tuning the unit for your setup. After poking around quite a bit on this- it looks as though a programmable unit called the "Prominator" is the way to go (go to the www.thirdgen.org (http://www.thirdgen.org) TBI forum to look into this unit)- but that's an additional $300.00 or so for the deluxe unit.

And don't forget- you need to get an electric fuel pump and upgrade any rubber gas lines that may be in your car now (TBI is only about 15psi- but better safe than sorry I think).

You also need to check the lobe separation of your cam. If its too far apart your car won't idle properly, it will search for an idle. I have a 91 chev truck that HAD TBI, nothing but problems. I think JET makes a chip to fix it but it'll cost as much as a new carb. Don't do it, your sanity will thank you for it.

from my experiences so far with my 92 camaro i just bought recently that has TBI, its a pain, TBI = Computer, 2nd gen camaros = hot rod = bad ! ull be cleaning the injectors alot and be tuneing the unit quite a bit for almost a overall nothing gain, and i belive you have to have certian heads or something to use TBI. if i where you and looking for anything kind of gain id go out and buy a AirGap Edelbrock intake and a nice cfm holley dp carb. Holleys highend carburators are so adjustable u can almost get the responce that you get from fuel injection with em if probley tuned.

thanks for the help everyone, I think I am going to keep the carb setup for now. Plans for a new engine are in the makings so fuel injection will have to wait until then.

I did quite a bit of research on this topic. I was planning to do something similar. The GM 5.0L and 5.7L throttle bodies are the same with different injectors. They flow around 450-500 cfm. The real problem is they only support 2 injectors. You MUST be able to flow enough fuel to support your engine's demand or you will be lean and that is bad. The problem with using 2 big injectors (45, 55, or even 65 lbs/hr each) for high horsepower is that you do not have very good control over them at idle/low speeds.

My plan was to make a plenum that would bolt to my current Edelbrock intake and that would mount 2 TBI units. I was going to run 4 injectors at 55 lbs/hr each and use the DIY Megasquirt controller (http://www.bgsoflex.com/megasquirt.html). I also considered using an Edelbrock dual quad intake and 2 TBI adapter plates and briefly though about using a Crossfire manifold from a mid 80's 'Vette. I have collected several TBI units and rebuilt them, I have a fuel sending unit from a 3rd gen with integral pump, I just have not had the time to mess with it.

actually, I wasn't thinking about the fuel flow, rather the airflow. 450-500cfm is going to be pretty restrictive to anything but a cruiser. The 454 units are supposed to be bigger, and Holley also makes larger TB's. Holley also makes a 4V TB for their Pro-Jection, but I don't know if that will work with the GM computer.
I have thought of using 2 GM TB units on a dual quad, or tunnel ram manifold. You would need two computers, but that would give plenty of airflow, and the computer controlls should take care of throttle response just fine.
If the 4G guys can get a hi-po engine to idle fine on the street, I think we can, too. I have heard of the problems with larger injectors, but since a TBI has the entire plenum to disperse fuel, it would probably do better than point injection.

Simpo - I thought TBI (and other computer-comtrolled engines) wanted a larger LSA to provide a strong vacuum signal. I know most of the guys with the computer-controlled Q-jets have around 112-14* LSA, as opposed to our usual 110* or so and the lumpier idle it gives. The larger camshafts I'm told confuse the computer into thinking that the throttle is further open than it actually is, and dumping too much fuel.

Special heads are not required for TBI. The factory used some crappy heads on some TBI engines, but that was trying to increase lowend torque and mileage.
One of the mags, CarCraft, or Chevy Hi Performance, did a TBI 305 Camaro build sometime recently with Vortech heads. I don't have the article offhand, but they got really impressive power out of it once they had the chip tuned up well. Probably would have outrun a number of stock-head 350's.

The trouble with big injectors is that even at the shortest pulse widths they put out too much fuel...

The Megasquirt can easily control 1,2,4,or 8 injectors. Just tie the throttle linkages together, use only 1 TPS, and you have it.