81 Computer Removal
Thread Starter
Burning Brakes
Joined: Dec 2001
Posts: 1,003
Likes: 0
From: GA
81 Computer Removal
Am I right in assuming that the computer on a 81 controls only the carb and the the transmission. I was wanting to remove the computer and replace my intake and carb with a noncomputerized one. What would I need to get to make the transmission still operate normally. Also when I get a new intake do I need one with the egr hookup or not. Was looking at the performer.And yea I know I might as well do a cam swap.
Safety Car
Joined: Mar 2000
Posts: 4,077
Likes: 27
From: Northeast South Dakota
Re: 81 Computer Removal (Armstrong)
Your computer controls the carb, torque converter lockup, and timing advance. To do away with the carb, you will need a different carb, and a distributor at least. The transmission will still operate, only you won't have any lockup. (If I'm wrong about this, somebody let me know) You can get a vacuum switch to make the lockup work properly without the computer. I don't remember who it was that has that setup, seems like it's Gator81, but I'm not sure. I'm sure they'll post what car they got that vacuum switch for the lockup off of. I don't know for sure if you want to go with EGR or not. Either way, the computer isn't needed for EGR.
John's 81' mouse, UKPaul, and Gator81 would all be good ones to take advice from on this topic. Come on guys, where are you? :D
John's 81' mouse, UKPaul, and Gator81 would all be good ones to take advice from on this topic. Come on guys, where are you? :D
Melting Slicks
Joined: May 2001
Posts: 2,700
Likes: 3
From: Lebanon KY
Re: 81 Computer Removal (Dalannex)
I am planning on taking all that computer and alarm wiring out of my 81 after it warms up. Probably this spring/summer. Dalannex is right about what the computer controls. As for allowing the lock-up torque convertor to still work without the computer, just use a switch. I bypassed the computer and hooked mine up to a switch. Mine was just a regular switch, not a vacuum one. But I probably wired mine up different. :confused:
Safety Car
Joined: Mar 2000
Posts: 4,077
Likes: 27
From: Northeast South Dakota
Re: 81 Computer Removal (corvettemaster)
That's correct. They can be wired onto a switch. I think that's how most people do it, but with the vacuum switch method, you get a vacuum switch off of some car or another at the old salvage yard, hook your tranny wires up to it, then hook it up to manifold vacuum and it locks and unlocks the converter for you. Just like factory, only without the computer.
Justin
Justin
Abby Normal
Joined: Dec 2001
Posts: 53,311
Likes: 92
From: Press "2" for English
Re: 81 Computer Removal (Armstrong)
what is wrong with the computer in your '81? i can't think of anything that would make me want to get rid of mine. burns clean and gets over twenty miles to the gallon on flat ground. what is your car doing that you want to get out of the computer controls? and if you really want to, i'd be interested in the computer, distributor and carb.
Burning Brakes
Joined: Dec 2000
Posts: 1,183
Likes: 2
From: Des Moines Iowa
Re: 81 Computer Removal (Armstrong)
If you don't want / need the EGR, you can go with Edelbrock Peformer 2101, that's what I have. Must install different HEI distributor, one that has vacuum advance, and then wire switch or use vacuum controled switch, like Justin said, if you want lock up torque convertor, which is advisable, if you do highway driving and mpg, is important to you.
Don't go too wild on cam swap, if you still have original rear gears. Too much duration will destroy your low end torque on this L81, low compression engine.
Suggest you consider replacement or elimination of Cat Convertor, and going to dual exhaust as well.
Don't go too wild on cam swap, if you still have original rear gears. Too much duration will destroy your low end torque on this L81, low compression engine.
Suggest you consider replacement or elimination of Cat Convertor, and going to dual exhaust as well.
Safety Car
Joined: May 2001
Posts: 3,758
Likes: 3
From: Surrey
Re: 81 Computer Removal (clutchdust)
what is wrong with the computer in your '81? i can't think of anything that would make me want to get rid of mine. burns clean and gets over twenty miles to the gallon on flat ground. what is your car doing that you want to get out of the computer controls? and if you really want to, i'd be interested in the computer, distributor and carb.
The EGR & AIR system has been removed from mine with no bad effects.
Good luck
Paul
p.s. your computer (if you junk it) wouldn't have a performance chip in it would it? ;)
Thread Starter
Burning Brakes
Joined: Dec 2001
Posts: 1,003
Likes: 0
From: GA
Re: 81 Computer Removal (Armstrong)
Thanx to all replies. At the present time I am just considering this. Your response's help me decide. Just bought this Beauty and it needs alot of work. Right now the engine runs GREAT! All smog junk has been removed and I have loose wires running all over the place. My exhaust has the tubes sticking out the top of the tube manifolds. It does have true duals and the cat system has been removed. Just trying to figure out where to go from here for now. John's 81 Mouse sounds about what I want.
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Safety Car
Joined: May 2001
Posts: 3,758
Likes: 3
From: Surrey
Re: 81 Computer Removal (8T1-7T9 BIONIC VETTE)
I have the computer out of my 1981.......you want it.....you pay cost of shipment.....it's yours....Cappy :seeya
:cheers:
Paul
Safety Car
Joined: May 2001
Posts: 3,758
Likes: 3
From: Surrey
Re: 81 Computer Removal (clutchdust)
o.k. paul, if cappy's computer is for a stick, it's mine--if it's for an auto, it's yours. sound fair? cappy, you out there?
Burning Brakes
Joined: Aug 2000
Posts: 1,239
Likes: 0
From: NY
Re: 81 Computer Removal (UKPaul)
Just unplug the computer.....no need to take it out. It's in the battery compartment anyway.
Put in a GM HEI distributor and get a B&M lock up switch.
It plugs in to the trans and the speedo cable. Lock it up or leave it unlocked at whatever speed you desire. It works very nice. A small green led shows locked and red is unlocked. Adjusts on the fly.
[Modified by 81ZZ4, 9:59 AM 2/4/2002]
Put in a GM HEI distributor and get a B&M lock up switch.
It plugs in to the trans and the speedo cable. Lock it up or leave it unlocked at whatever speed you desire. It works very nice. A small green led shows locked and red is unlocked. Adjusts on the fly.
[Modified by 81ZZ4, 9:59 AM 2/4/2002]
Burning Brakes
Joined: May 1999
Posts: 1,179
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From: waller texas
Cruise-In I Veteran
Re: 81 Computer Removal (Armstrong)
I have an 81 also and my cmputer is not connected and my lock up is not working.Is there a wire coming out of trans case for lock up and if so where might it be?I only get around 15 mpg and would like to see 20mpg.All my smog parts removed and hei dist with quadrajet carb.
Thanks for the help. Wave on ! \ ////
Thanks for the help. Wave on ! \ ////
Safety Car
Joined: May 2001
Posts: 3,758
Likes: 3
From: Surrey
Re: 81 Computer Removal (all smiles 81)
Hi smiles!
There is a connector (assuming you've got a TH350) on the side at the left of the g/box. There are 4 contacts in the connector, only 3 of which are used. The wires that attach to the connector run up the side of the engine to a harness connector somewhere around the rear of the drivers side valve cover.
You need to connect a 12V supply to the A terminal (an ideal supply would be the one from the TCC brake switch - then your converter would unlock when you hit the brakes) & run the D terminal to a switch somewhere inside which you'd use to lock/unlock the converter. The C terminal is some sort of gear indication to the ECU & the B terminal is unused. All that happens with the computer is that it earths the D terminal when it wants to lock the converter, so you'd just be replacing an expensive computer with a cheap switch :)
The 12V supply from the TCC brake switch is a purple wire? (this is from memory :( so could be wrong!) that connects to the TCC/EGR bleed relay.
:cheers:
There is a connector (assuming you've got a TH350) on the side at the left of the g/box. There are 4 contacts in the connector, only 3 of which are used. The wires that attach to the connector run up the side of the engine to a harness connector somewhere around the rear of the drivers side valve cover.
You need to connect a 12V supply to the A terminal (an ideal supply would be the one from the TCC brake switch - then your converter would unlock when you hit the brakes) & run the D terminal to a switch somewhere inside which you'd use to lock/unlock the converter. The C terminal is some sort of gear indication to the ECU & the B terminal is unused. All that happens with the computer is that it earths the D terminal when it wants to lock the converter, so you'd just be replacing an expensive computer with a cheap switch :)
The 12V supply from the TCC brake switch is a purple wire? (this is from memory :( so could be wrong!) that connects to the TCC/EGR bleed relay.
:cheers:
Race Director
Joined: Feb 2001
Posts: 10,787
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From: My own state of mind
Re: 81 Computer Removal (Armstrong)
Also be careful as a lot of emissions testers will look for the Check Engine light to come on for a few seconds when they start the car. Best solution to this is to wire it up to the choke light.
I'm planning on keeping mine until I do my ZZ4 swap in 5 years when I graduate. By then I won't have to E-test it. I'll be safe though and get a chip for the ZZ4 for the computer so that if I sell it I can hook up the comp and everything (carb, dist, tranny) so that it'll pass an E-test. I don't have any plans of selling it though but it'd be safe to keep just in case!
Matt
I'm planning on keeping mine until I do my ZZ4 swap in 5 years when I graduate. By then I won't have to E-test it. I'll be safe though and get a chip for the ZZ4 for the computer so that if I sell it I can hook up the comp and everything (carb, dist, tranny) so that it'll pass an E-test. I don't have any plans of selling it though but it'd be safe to keep just in case!
Matt
