Hi all,
i noticed that my FD speedometer is off by 12 km/h at 140 km/h (reading 140 km/h when accurate gps speed is 128 km/h), which is a 8.5% error, really too much.
Is there a way to fix it and reduce this error to 2-3%?

Best Regards,
Giorgio

 

do you have a non-stock sized tire and or wheel on the car?

 

Might you also have a non-standard rear drive ratio? (Automatics are 3.90, manuals are 4.10, and in the JDM market I think there are some 4.33's floating about)

As well, if you have 100% stock drive ratio and tire size, have a look at whether the speedo sensor might be changed by accident. There is a different speedo sensor for each final drive ratio.

 

Car is stock for what i know. Maybe i can take a look at the speedo sensor tomorrow

 

What tire size?

 

225/50ZR16, it's stock

 

your limited slip or non limited slip diff its whats causing this

 

Hi LoTim,
what do you mean?
LSD is broken? Maybe a fluid change will solve?

 

No, that's completely unrelated.

This is a tire size / speedometer gear / rear end ratio problem.

 

Is there a way to check the rear end ratio?