Speed calibration

Christian · Post by **Christian** » Mon Jul 27, 2009 4:43 am

Hi

I have installed the diff off a S14 into my S13 to have longer gearing.

Is there a way to adjust speed in Nistune? Consult vehicle display shows 135 km/h when I'm driving 148 (tested with GPS).

I have tried tyre size speed correction in configuration, but that doesn't change anything.
I'm on version 0.9.12b

Cheers
Christian

Matt · Post by **Matt** » Mon Jul 27, 2009 1:06 pm

the speed calibration should have worked in 0.9.12b. i tried out different tyre sizes and it altered the output speed figure

i'll have to have another look at it if you think its not doing its job. I based the calculations from a tyre size webpage i found and compared their calculations against my own, and then offset the output speed by their comparisons

what values are you entering in?

Rich S · Post by **Rich S** » Tue Jul 28, 2009 4:41 am

you can always adjust the potentiometer on the speedo itself. You'll have to remove the speedo from the cluster to do it.

Christian · Post by **Christian** » Tue Jul 28, 2009 6:28 am

Hm, strange.

I entered 195/60/15 as OEM size and 215/45/17 as current size.

I tried to change wheel inches to 18 and 20 in current size and I altered the tire to 215/65/17. Both did nothing.

Rich S, I already did that, my speedo itself is spot on. It's the Nistune printout I want to calibrate.

Thanks guys
Christian

Christian · Post by **Christian** » Tue Jul 28, 2009 7:13 am

Forget what I said.
It seems to work.

I'm a bit confused now...
I did a reboot of the laptop and normally only send it sleeping. But that can't be it I think?

On which diff is Nistune based? I suppose JDM, correct?
Stock european S13 has 1:3.916 and I changed it to 1:3.692.
What would be the correct setting with 215/45/17 tyres?

Christian

Matt · Post by **Matt** » Tue Jul 28, 2009 11:25 am

nistune just reports the consult reported speed from the ECU 'as is'

The speed signal coming from the transmission sometimes gets calibrated by a potentiometer (in my R31 thats in the speedo unit) and then goes to the ECU as pulses

The ECU just measures the pulses to determine the speed, and Nistune reports the number given it

Good to hear the speedo calibration worked ... that just tweaks the displayable number on your laptop based on entered figures.

Not sure what tyre numbers you would enter for those diff ratios?