Speedo misreading

[Guest]

I got a BP5 legacy gt 2003 model. The speedo seems to be out by an above average amount (judging by those digital speed signs). I know the manufacturers purposely put them off by a few k's but mine is out by 8-9kph

To do 50 my dial shows around 57, and to do 100kph I have to go close to 110kph.

This doesnt bother me at all since I know now and just compensate when i drive (plus it makes my 0-100 time look extra quick ) but I was just wondering would this affect anything else?

For instance would my odometer be increasing at a faster rate?

[94 Leone]

It'd just make your odo build up slower If you just travel at the marked speed.

[DRFVDR]

yup the odo will be out by the same amount,

is it running stock tires/wheels as this is usually the culprit..

next time you change tires put smaller diametre one son it to compensate ( smaller series not rim)

[GC8E2DD]

I think you want bigger OD tyres, not smaller.

[Kiwi_Fozze]

yer, mines reading 60 at just on 50. so i'm sitting at close to 120 indicated at 100km actual.

kills my fuel usage, slightly slower trips, awesome acceleration

it racks up miles a bit quicker too, as it thinks you are travelling faster / further than you actually are.

[mac]

Most suby's speedo's are calibrated for 16" rims running 205/50/16 tyres im thinking, may be wrong but hey we all maka da mistake sum time.

[Guest]

It's a spec B so it has the standard 18" rims. Tyres currently on it have the same specs as factory as well so I guess it might just be a case of subaru not calibrating for each specific model, maybe using a 'general' one for all BP5's.

Is it simple to re-calibrate? Need to be on a dyno and plugged in?

[mac]

:'( I have no idea if you can re-calibrate the speedo, late model electronics are a little above my old school mechanical brain.

[mondo]

Most under read by 5-7 kmh, and those speed indicator signs can vary up to 10kmh with the weather.

[Swindog]

Both my wrxs read 10km under. So 100kmh reads as 90km actual speed.

[Stoffa]

http://www.jaycar.co.nz/productResults.asp?keywords=Speedo+Corrector+MkII+Kit+&keyform=KEYWORD

mines the same but when I get around to it, im going to wire the speed sensor directly to my link then use an out put to run the speedo so I can adjust it easily