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Old 01-01-2011
S281SC Coop S281SC Coop is offline
Senior Saleen Forums Participant
Join Date: Nov 2005
Location: Northern Ohio area
Posts: 297

I had the same issue with the clock on the dash running at a different speed than what my GPS unit was telling me I was going. A couple things are going to affect, the first being your rear-end gear ratio. If you have a hand held tuner (SCT) you need to hook it up and be sure you have the correct ratio "loaded" into the cars computer. The second thing that is going ot affect it is your tires RPM (revoultions per mile) this is something you can toy around with but you have to reload it everytime you change the perameter.

If I remember correctly mine was set around 735 and this was way off. my clock was telling me I was going 70 and my GPS said I was only doing 66,,,67. but taking that 735 number higher I was finally able to get my GPS and clock to agree on the same speed. Good luck

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