speedometer

[nissan_240sx]

hmm i just notice that my mph seems to be going up just alittle fast, so i asked my friend to drive right beside me at 35mph, i look at my speedo and it shows 40ish mph. anyone know whats up? lol ive done a few research and it seems that quite alot of 240 owners have this prob. thanks,
Peace!-

[slideways...]

stock wheels/tires?
running different size diameter tires will affect speedo readings

[atamotua]

yeah... slapping on smaller radius/diameter wheels will make you think you go faster if you go by the speedo... i did that once and my speedo was showing 90 or so and the actual speed was maybe 75 or so...

[coolbone28]

ya what atamotua said...except in your case you would have to have bigger wheel circumfrence, whcih would make you go faster with less rpm of the tire...hence your speedo thinks you are going slower. also if you changed your diff. to say a j30 vlsd the gearing is different which will do the same thing.

[240SXSlideStar]

Is there a way to recalibrate the speedo?

[coolbone28]

whoops read it wrong...disregard my post...unless you find yourself going faster than your speedo sayd. haha as far as recalibration, you might want to check with local mechanics maybe even performance shops with a dyno. cant hurt to ask =)

[atamotua]

COOLBONE... i said exactly what "nissan_240sx" said.... my case is the same as his... you're right about what you said too, but that's not his problem... his speedo is showing higher speeds then the car is actually traveling...

so to clarify things for everyone who may read this.... when you put on BIGGER WHEELS you'll be going faster but your speedo will show that you're going slower... in this case you need to be careful and adjust your speed accordingly so you don't get pulled over..... when you put on SMALLER WHEELS your speedo will show you higher speed than what you're actually traveling at... this is not that great for the engine, since the engine has to rev up higher to achieve the same speed you used to travel at when you had stock wheels on...

[atamotua]

RECALIBRATION - i think it is possible... at least the guy who's gonna modify my RB25DET wiring harness told me it is... you'll need something like this http://cgi.ebay.com/ebaymotors/ws/eB...ME:B:EOAB:US:6 ... it's a DAKOTA DIGITAL SGI-5 .... i don't have details on how to wire it up... it comes with instructions though and you can ask around some wiring gurus who may be able to help you... talk to this guy right here Yury Lyalko

www.wiringspecialties.com

[email protected]

[orestes]

so not really a recalibration just put in a new unit?

[LaYzIeNoY]

i know that some shop can do it

they adjust the speedo to read properly, it changes the calculations sued to rated your speed

[nissan_240sx]

Originally Posted by coolbone28

ya what atamotua said...except in your case you would have to have bigger wheel circumfrence, whcih would make you go faster with less rpm of the tire...hence your speedo thinks you are going slower. also if you changed your diff. to say a j30 vlsd the gearing is different which will do the same thing.

Yeah i guess its the rims, i have 17's lol.


and thanks for the links atamotua