R34 Nismo Instrument cluster 10km/hr speed inacuracy

[jezzrrr]

I recently (5K ago) installed a nismo speed cluster on my R34 GTR and it reads 10km higher than actual speed. I never measured the standard one so I dont know how they compare - I was able to tell the error when the car was on the dyno.

Has anyone experienced this with Nismo dash on GTR's ?

[Jay95R33]

Do you have stock rim/tyres ?

If you don't, then make sure they are the correct rolling diameter, otherwise that will put your speedo out too.

J

[tomj]

I was thinking the same too

VDO can reset it to work properly Jeremy

[Abo Bob]

And all speedos are out anyway. Even my AVC-R and my speedo don't say the same thing and they take the same signal! It get's worse the faster you are going.

At what speed was it 10 out or does it say 10 when you are sitting still?

[wld33r]

rolling diameter wouldn't make 10k diference??? only couple i think?!?!?!?!

[Jay95R33]

rolling diameter wouldn't make 10k diference??? only couple i think?!?!?!?!

Depends on how different the diameters are !

10km difference at 100km/h is only 10%. Doesn't take much to be out by 10%.

From factory I think the specs are +/- 3% to pass ADR's

This web page can help you to work out how far your speedo wil be out if you change tyre size.

http://www.secret-secret.com/turbo/DIY/tir.../turbotire.html

J

[jezzrrr]

I was cereful on that issue when I changed wheels and tyres, went from 245/40 18s to 265/35/18 which is only 1.53% difference so thats not it

[Jay95R33]

Hmm, then I'm not sure.

Maybe the speedo cable/screw drive is worn or has previously been replaced with a slightly different sized one?

Or maybe you are correct in saying that the speedo is infact out.

Hard to say really.

Here in Canberra we have speedo checkpoints on some of the main highways. Basically just markers over 5km distance so you can check your speedo. If they have any around your area give them a try, maybe the dyno was out

J

[jezzrrr]

The only speed checks we have are speed cameras I might take the front plate off and do a check !

(kidding)

[Jay95R33]

Hahaha - I wonder if you could do that? Find a speed camera van and ask if they could check you speed ?