Which jumper is #8??!! Im going to jump off a cliff tonight , I cant verify which jumper is the ground / #8 . Ive got everything ready to calibrate it from 3.42 to a 4.10 ratio but I only see the 7 jumpers and cant find a schematic for them!

 

There is no jumper #8 on a DRAC. The Programming clip on some instrument clusters has a pin #8 which is the common or "ground" pin. Removing the common pin on a programming clip will ruin it as none of the other pins will have a current return path. I have a file that I downloaded from the diy-efi ftp site (which is down at this time or I would have put up a link) that I can e-mail you which explains all about the DRAC. Let me know.

 

Cool , thank you very much .

 

can some heelp me go from 273 to 342 with a step by step for the drac unit?

 

http://614streets.com/drac.html

Thats all you need to do Cobb

 

I looked by my ecm and i can not find the drac unit, i think i might have to take apart the dash, so were is it, in a 90 camaro?

 

No 3rd Gen Camaros or Firebirds use a DRAC.

IIRC mostly trucks came with them.

RBob.

 

Than what do i do is it the same thing

 

By the previous post you changed the rear gears and now need to get the speedometer in line. If so then there are two gears in the transmision tailhousing. One or both (usually just one) of those gears will need to be changed.

There is more info on the tranny board for this change.

RBob.

 

Ok i found the drac unit on my 90 camaro but is does not look anything like the info i found on it, in the info they talk about a ussb unit which is under the speedo cluster. Texes instruments makes these. Does any one know how to fix the speedo with these. For now i know that i need to change the resister value from the outout of 2.73 to 3.42 with a 275/40/17 tire.

Thanks Tony C.

 

Thats because your car doesn't use a DRAC, what you found is most likely a VSS buffer box. I believe alot of the early-mid 90's chevy trucks use a DRAC module, both minitrucks and full size.