question about TACH and Speedo
Thread Starter
Junior Member
Joined: Aug 2012
Posts: 56
Likes: 0
From: iowa
question about TACH and Speedo
Ok so I replaced my rear differential froma stock 2.42 over to a posi 3.23. In doing so I replaced my DRAC module with the DRAC out of the car I go the differential out of. this should have put my speedo dead on. (Its not!!) and ever since I have gotten the car the TACH reads about 200-300rpms higher than what the scanner says it is actually doing. Does anyone know what would cause this?
BTW, I have a 91 Z28 with 700r4. So speedo is electronically controlled by ecm and DRAC...no gears to change to alter.
BTW, I have a 91 Z28 with 700r4. So speedo is electronically controlled by ecm and DRAC...no gears to change to alter.
Joined: Apr 2005
Posts: 7,736
Likes: 14
From: Not in Kansas anymore
Car: 82 Z28
Engine: 383 SP EFI/ 4150 TB
Transmission: T400
Axle/Gears: QP 9" 3.73
Joined: Apr 2005
Posts: 7,736
Likes: 14
From: Not in Kansas anymore
Car: 82 Z28
Engine: 383 SP EFI/ 4150 TB
Transmission: T400
Axle/Gears: QP 9" 3.73
Thread
Thread Starter
Forum
Replies
Last Post