hi everyone. im in australia and have a 81 vet. i have owned it for 3 years and got it over from california .all this time i havent really touched it except for new paint. i have only now just decided to do it up and make it boogey. first i have changed the gearing in the diff from the standard 2.74 to new 3.55 gears. that has helped alot. now ill be putting in a 2500 stall and doing the motor up next but i dont really know anything about how the computer works. from what i have been reading it only controls a few things like mixture and timing. what i would really like to do is get rid of it all together but im not sure if its possible. whats the best way to go about making any changes in this area because im worried i may do all this work to the motor and the original computer might hold its performance back ? i have already ripped out everything that is to do with the polution parts as we dont have the same laws over here for that stuff .

 

Early EFI sucks. If you don't need it for leagalty reasons then my opinion is to yank it out and replace it with either a good carb and manifold setup, or a newer aftermarket EFI system. You and your Vette will be much happier. It's easy too. Just pull the whole manifold/EFI assembly and replace with a new manifold, carb, distributor, and intake. Install a new fuel pressure regulator, set at about 5-7 lbs. of pressure. EFI uses higher pressures then carbs do, although the early systems are not that high compared to newer ones, they are still more than a carb likes. There may be some miscellanius things like sending units for you gauges and wiring your distributor and other items (I'm not intimitly familier with 81's). If you do go through with this swap, get yourself a copy of the A.I.M. for your year (Assembly instuction manual) as well as any other literature you're happy with. And there are plenty of knowladgeable people here on the forum that will help.

 

i was asking about the computer thats behind my seat near the battery compartment that came in on the 81,s. what are you talking about efi for and all the rest of it ? did you reply to the wrong post?

 

here is my 2 cents, do not get rid of your computer unless you are prepared to replace it with another system. you might have a `81 TBI (throttlebody injection), 1982-1984 crossfire injection, 1985-1993 TPI (tuneport injection), 1994-1997 LT1, 1997-2004 LS1. in my understanding, most cars have some type of computer system even with carburetors.
they all work and have thier own characteristics. thanx

 

You can dump the computer, you have to switch out the distributor and the Carberator. The CCC only controlled the distributor and the carb. Do not throw your computer away - They are no longer available and are only being rebuilt as far as I can tell. If you don't want it, sell it on eBay or on here.

 

Well, the CCC actually controls more than timing and fuel mix, thats just the rngine operations. It also controlls EGR, Torq converter lockup, air pump operation, and I am not sure but I think it empties the ash tray (I don't smoke)
You can dump the computer, but be aware of what else will need attention: TCC and SMOG components if you need to deal with that.

 

Agree with what you said but I think he's dumped the smog stuff and I forgot about the auto tranny - mines manual.

 

I've got an 81, and when I got it, the previous owner had already removed the CCC. What he did was replace the carb, cam, and distributor with 1980 units and left all the wiring in place. Left quite a mess. A bit of a Bubba job, if you will. There's loads of wiring left under the hood, and quite honestly I don't know what's working and what's not. It does run quite strongly for a restricted 350, though. He said it wasn't that much work to do, just make sure you do everything right.

 

I've got an auto tranny and no computer, but as far as I know, previous owner didn't do anything to the tranny.

 

OK, gotcha. So what you need to do is follow each wire from its sensor back to the wire harness at the firewall. There are 2 flat connectors coming from the harness back behing the distributor. Those are the sensors and outputs associated with the CCC system. You should be able to disconnect them, keep them. From there you can see the other bits on the engine that can go as they do not operate: Air Pump and diverter valve, Temp sensor in the manifold next to the Thermostat, EGR solenoids (2), there may be others but I don't have a book here with me.

 

Umm...81s didn't have fuel injection, they had a Rochester E4ME electronic carburetor.

The 82 Cross-Fire injection system is actually a pretty good design, it just needs some tweaking. The manifold was based off of the late 60s Camaro 302 crossram.

 

here is a few pics of my engine bay with no polution gear.( yes its a tight squeeze with the steering box on the right side) it is only going to look like this for a few more weeks till my parts arrive. i have a demon mighty 750, edelbrock heads, air gap manifold and a dizzy on order.then put extractors on it and tidy up with some paint and make all the ugly wiring and loose ends dissappear and it should look alot better.bye bye computer.

 

Hi,
A couple of questions:
We stopped in at a Vette shop near Brisbane & the guys there said that you had to have right hand drive after a certain year. Is that still the case?
What ya gonna do with the computer? If you are going to chuck it out can I give you a few tinnies for it? You wouldn't need to worry about posting it to the UK, just to Stanthorpe, QL.

 

yea sure paul no worries.the age for cars is 30 years. you can still get a special club rego i think for newer cars but generally 30 years ,yes and they can be left original. im just doing my homework now on which way im going to go. these 81,s sure are a real hassle to get hookin up off the line over here. just getting my diff to a 3.55 ,replacing trailing arm bushes,strut rod bushes was a real drama . i had to order everything from U.S. at least my **** end is all perfect now but as i move my way up the drive line it gets harder. im just being really carefull to get this computer/or no computer set up right ! i have now come to the dilemma a B&M 2500 holeshot converter may not fit the TH350C transmission. buying an 80 would have been so much easier !! haha
sure if i do lose the computer ill send it to good old stanthorp(freezing)for ya!! a carton of corona should cover it !

cant wait to get rid of this ugly exhaust but it will be the final piece in the puzzle.

 

Hi,
Just let me know if you're going to junk it & I'll sort out a carton of corona And Stanthorp is freezing, it's colder than here!!!
What I did with my '81 was to finish off the removal of the emissions control stuff (a few bits were left hanging, vac leaks, etc), fixed the bent "dancing needle" in the carb & found that it ran pretty well, also giving good fuel economy. So I figured that as the computer was working then it would be stupid to remove it for no reason, other than spending a wedge of cash getting a new carb & dizzy. A wild cam (that would drop vacuum down to the point that the computer would freak) isn't n option as I can't afford the fuel economy that would result; I do fairly long runs & with fuel at about $9/gallon it'd get painful pretty quick.
Changing the stock exhaust for true duals (2 1/2") was the best mod I ever did for performance, the engine actually felt alive & responsive afterwards. But I found that the power dropped off higher up the rev range, like it was being strangled, & it turned out to be due to the restrictive manifolds. I then fitted Dynomax ceramic coated headers & made up a new exhaust, rather than buggering about cutting & welding up the Mid America true duals that were on it. This is worth considering if you want to modify the exhaust. As I had just fitted a BTO 200-4r OD trans (THE BEST mod I've done to it ), I had an x-member with clearance for exhaust pipes on both sides, so I could run a pipe down each side of the car. With a stock x-member you can cut a scallop (curved chunk) out of the drivers side of it & then weld a metal plate over it so that it has clearance for an exhaust just like the passenger side does. Then get an exhaust shop to supply some 2 1/2" stainless pipe. All you need are 4 bends done in the entire system, two for each side. You'll need a 15* bend just behind the headers so that the exhaust runs parallel to the underside of the car (the headers point down slightly) & then an 85* bend at the rear so that it kicks out to the mufflers like the original. I did mine in sections, expanding the ends of some parts to give a slip fit. This allows a bit of jiggling into position so that you can get it all lined up. Here's a pic (mess due to an oil leak!):

The lowest part of the system is just below the drivers floor & gives 3" of ground clearance. If you do fit dual pipes then I'd recommend fitting an H/X pipe as it gives a much better idle & exhaust tone than separate pipes. And if you've got an oil leak, don't bother polishing the pipes before fitting them

 

Uhhhh, no I did not reply to the wrong post The computer controles that stuff, so you can't get rid of one without the other(or finding a solution).
As for calling it EFI, yeah I know it technicly is not, I just brain farted calling it that , but it is basicly an electronicly controled carb, just not injected, Any ways... there are aftermarket stand alone tourq converter lockup kits available. I think TCI and/or B&M make them, maybe others as well. They're designed for retrofiting lockup converters into older cars that didn't have them but would work for this as well.