I am fairly sure that you can easily program in a change in speedo for the 94+ flash based computer systems. Is it the same programming process for a 93 just with a chip?

My car has always had the speedo wrong, I got it from the original owner and right after he got the car he went from the stock "performance" 3.42s to 3.73s. Then he went to 4.10s and realized he liked the 3.73s more. Doing some calculations and research it appears that the car wouldn't have come with 3.42s stock but more than likely 3.23s and my speed is reflecting over 20% higher than it should (70 on the speedo is about 55-56mph). My 93 was very late in the production as it was custom ordered, build in mid April of 93 and did not get the corvette transmission, the tag on the rear does call for 3.42 gears, leading me to believe he may have switched the rear end.

Anyway, some time back, before i got my car tuned i was having weird problems with my speedometer. During "heavy acceleration" my car wouldn't know what speed it was going (speedo would bounce around between 30-60mph as i was driving a constant speed in gear. Later I found out that the chip the previous owner had burned for the LT4 conversion kit was actually for an auto transmission car. This explains some of the problems i was having, needing to adjust the throttle stop screw up to increase the idle specifically.

Sorry i got a little long winded. Anyway question is, how do i fix the speedo (even though it won't correct the mileage on the car which should be about 85k miles instead 112k). On the foxbody i used to have it was a simple gear change in the output shaft of the transmission (mechanically driven speedo). I know these use electrical pulses that get read and interpreted.

Thanks for the help.

 

The Corvette never used the T56 for the LT1 (or any previous engine) - so that part of the explanation falls apart. All the 92-96 LT1/LT4 Corvettes used a ZF 6-speed, manufactured in Germany. April 93 is not "late production"... maybe something in July might be. I've never seen a "tag on the rear" of a 4th Gen.... what is the RPO code shown on the build tag for the stock gears - GU2 (2.73); GU5 (3.23) or GU6 (3.42)? Is there an "M28" or an "M29" shown on the build tag?

 

I apologize if I'm wrong, I read an article a while back that the early production 93 camaros used surplus transmissions from the corvette production run, hence the different gear ratios. This article must have been wrong. I can check the codes out if it is necessary, but my main question is how would I fix my speedometer?

 

Dakota Digital is the calibrator many use, myself included.