Speedometer issue after transmission swap

[em-power]

Hi guys, i bought a TT SUPRA auto, but this car has been converted to manual 10 year ago (i found the recipt with the costs paid for the work... ex owner paid only 700gbo for a 6speed getrag v160.... my goood)

Anyway, the car have this problem now:

The speedometer, do not read in the correct way the car speed.

Seems that the rpm are ok, but the real speed is not correct. When car is around 100 km/h it sign 140km/h

I aslo tried with gps to switch from km/h to mp/h but both are wrong.

 

 

 

And also the led odometer read more km than the reality. If i drive for 10km it show more than 16km

 

It may depend from the Lsd? Maybe who made the transmission swap do not change it with the manual version? Or maybe i have to change some speed sensor on the car ??

 

Thank you, sorry for my bad english i hope you can understand

 

Luca

Edited October 9, 2018 by em-power (see edit history)

[Edvard]

Hi Luca,

 

Did you look under the dash or behind the speedo for the speed converter? It seems that you have one connected to the spedo and odometer. Because you said that you drive 10km and it shows 16km...1 mile is 1,6 km...so your odometer shows miles and not kilometers.

 

Hope that you understand what I mean.

[Mika]

The easiest way to correct the speedometer signal is the YellowBox speedo corrector, have a look (most likely your differential has not been change to the 3.266 ratio diff):

 

https://www.supraforums.com/forum/showthread.php?671481-Installing-a-Yellowbox-V4-speedo-corrector-in-a-Supra-MKIV-SC

 

https://www.google.com/search?q=toyota+supra+yellow+box+speedo+correction&ie=utf-8&oe=utf-8&client=firefox-b

 

It is a very handy device.