2001 speedometer help

[snkebit]

my speedometer is reading almost 10mph slower than it should be when the speedo says im doing 75. the car is running about 2500rpm in 5th at what i believe is 75. I just purchased the car and i know the clutch and synchros were replaced thoughts on if the car may have gears or any other explanation?

 

[K2AHollywood]

yes if its tuned, the tune may have been inproperly set for your gears, also anything like a speedcal can also throw this off. I dont see what your mods are but let me know and I probably can give you some good ideas :beer:

 

[snkebit]

the only thing done to the car besides what i already said is bassani exhaust true duals no cats. I got it from a dealer and he replaced the clutch and tranny work. Anything else would have been done by the previous owner.

 

[99riocobra]

you can check to see if it has gears in it. get the rear end in the air, count how many times you have to turn the driveshaft for every one turn of a wheel. ex: about 3.25 turns = stock 3.27's, a bit over 4 turns = 4.10's.....

 

[quick01snake]

if it is reading slower than it should be, then the gear ratio is lower than the computer thinks...my guess is it used to have gears, got swapped back down, and someone either left the program in the computer for the gears, or it still has a speedcal or similar attached to it...

 

[snkebit]

I meant to say its readin fast not slower... i ordered a tuner to calibrate the speedo i believe its got 3.73's. im gonna use my friends gps to estimate how fast im really going to see if i was right.

 

[quick01snake]

I meant to say its readin fast not slower... i ordered a tuner to calibrate the speedo i believe its got 3.73's. im gonna use my friends gps to estimate how fast im really going to see if i was right.

if the speedo is reading 75 when you are actually doing 65, then yes it sounds like you have 3.73's that were never corrected for...