Tire size compensation?

[GTMcoupe]

Hi team

Got myself a B18C installed in a Kitcar over here in the UK and running hondata obviously, now i have altered the gear ratios to suit my gearbox im using [custom mix of honda ratios] however seeing im running smaller diameter tires than a honda my ECU is reading a higher speed than im actually doing is there anyway i can compensate for this, struggling to find a option for it, still learning the system taking it slowly and easy with my changes

cheers

WEST

[Spunkster]

There is no compensation specifically for tires size, but you can change the final drive setting which may help

[GTMcoupe]

see i had thought this too, but when i thought about it, the VSS is direrct off the diff so after the final drive, unless of cause the speed is calculated from engine speed and gear ratios, but i thought it would had been a direct reading from the Vss otherwise why would you use a seperate sensor, ill give the final drive alterations a go in the next couple of days and report back if it works as was going to try this but thought id ask incase i had missed another available option, its not a necessity that the speed is correct but it would be nice for the datalogs of drag runs etc.


WEST

[GTMcoupe]

Right finally got to have a play today,

from a previous test i was finding that the S300 was giving me a speed 11% faster than what i was actually doing [before you ask i have a very acurate programable speedo fitted to my car]

as suggested by spunkster i adjusted the final drive value to see if this would effect the speed reading.

after a quick blast today with a altered value for final drive with a datalog, and a recall of max speed from my speedo still 11% out,

not a major problem just would had been usefull to get the ecu to agree with actuall speed for datalogged info when racing. prehaps a future little tweak/update.

cheers
WEST

[Hondata]

The gear ratio and final drive values are use for gear calculation, but have no effect on the ECU speed calculation.