Change over

akvette · 12-06-02, 10:55 PM

I am looking for advice on disabling my computer and installing an Edelbrock intake manifold and carburetor. I plan to own this car for many years and want to make it easier for me to maintain. Where I live in Alaska, I have not been able to find a mechanic yet who can adjust/tune this car. I want to be able to tune this car myself like my other noncomputerized vehicles. What is required to make this conversion? Also, any suggestions as to which parts? I also plan on changing the exhaust system since right now it sounds like a Chevette or a Vega. I will not be putting on a catalytic converter so I was wondering if there is a bolt-up exhaust kit out there. If any of you have already been down this road before, I'd appreciate hearing your input.

Thanks in advance,

Akvette

DDLS1 · 12-07-02, 09:09 AM

akvette,

Changing your 81 to a non-computer set-up is not too difficult. You will need to replace your carburetor and distributor with a pre-1981 set-up. You should also consider eliminating your egr valve and air pump. Accel makes an affordable HEI vacuum advance distributor I have had good luck with mine. MSD and Moroso are as good or better but more$$$$. If you want to stay with a Q-jet carb plan on spending about $460 on a new Edelbrock. I chose to replace my Q-jet with an Edelbrock Performer square bore for about $250. Since you plan on changing the intake the new Performer EPS looks like a super combo. Unless you plan to build another 200 horsepower into your engine soon, stay with the 600 cfm carb, no larger, or you will be tuning to lean it out big time. Unplug your ECM connectors in the engine compartment and tuck them back into the harness against the firewall. If you choose to go to the Square bore carb you will need to modify your fuel line and throttle linkage attachments. Everything to do this is available from Edelbrock, some of it comes with the carb some does not. I bought all my stuff at Summit Racing equipment. Complete exhaust coversions are also available with or without cats, from Summit, Zip, or even Ecklers. If you call Summit and tell them what your up too you will find their counter people very helpful and you may save some bucks over the vette catalog guys.

Dave L. · 12-07-02, 10:59 AM

DD-81 - I installed dual exhaust on my car 2 years ago and removed the long air pipe that went to the converter and disconnected the air pump belt. I am going to replace my intake manifold gaskets. I will be eliminating all the air equipment and plugging the air injection pipes. I was wondering if I will get a check engine light when I disconnect the electrical plugs from the air equipment, and if so what could be done if I do. Down the road I will be upgrading my engine and probably eliminating the computer set up all together. Until then,I would like to continue to use the stock distributor and carb. Whats your thoughts?

Thanks...........Dave

DDLS1 · 12-07-02, 11:29 AM

Dave,

Believe that your check engine light will indeed stay "on". Since it is all related to the ECM I would suggest removing the bulb.

Dave L. · 12-07-02, 06:18 PM

Thanks Dale,Good idea.

Dave

akvette · 12-12-02, 10:04 PM

Thanks guys for your help! Couple more questions....Since I have a 4-speed how will that affect my choice of distributors? Also, once I have made these changes will my factory spec's for engine timing remain the same?

DDLS1 · 12-13-02, 06:06 PM

akvette,

I know of no difference between a distributor used in conjunction with a 4-speed vs an automatic. You will need a vacuum advance, non-computer, HEI distributor, for a SB Chevy engine, pre 1981 style. Your timing is set using pre 1981 specs. Initial timing is usually 8 degrees BTDC.