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correcting my Spedo with my SCT

Old 03-08-2009, 11:43 AM
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JDWalton
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Default correcting my Spedo with my SCT

hey all, I got my SCT tuner and my custom tune installed in my stang, but for the life of me cant get my spedo right. I set it for 4.10 gears, and changed my tire revs per mile to what the calculators I have used call it. My spedo at 65 reads about 7 mils per hour faster then my actual speed. Should I adjust my gears or revs per mile, and if so, what way? Thanks for any help.
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Old 03-08-2009, 11:55 AM
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BruceH
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.......

Last edited by BruceH; 12-05-2010 at 10:39 AM.
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Old 03-08-2009, 11:59 AM
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thanks... though none of that is what I asked. lol. A better way to check my speed is to use my GPS on a straight road and compare. I just need to know if my spedo is reeding slow do I need to add or subtract revs per mile on the tuner.
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Old 03-08-2009, 02:30 PM
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Just go to the rear axel sections for gears and scroll done to 410 and reset tune. Speedo should be correct.
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Old 03-08-2009, 02:31 PM
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omg......
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Old 03-08-2009, 02:33 PM
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Originally Posted by JDWalton View Post
I set it for 4.10 gears, and changed my tire revs per mile to what the calculators I have used call it.
I appreciate some people trying to help but dam, the only 2 responses were what I already had done, and said in very first post.
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Old 03-08-2009, 06:12 PM
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Well fixed it. Going off what I had on my Predator was 721 to work, was like 7mph faster then actual speed. Changed to what a online calculator said, and went to 748. Was 5mph fast. Used the formula Bruce said, got 760 amd was 3mph fast. Following that path, added a arbitrary 20 to bring me up to 780 revs/mile and now I am within 1mph at 70. Thats good enough for me.
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Old 03-08-2009, 06:27 PM
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I've read several posts saying to use a GPS to check your spedo. Is the GPS that accurate? How accurate is it? Thanks...
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Old 03-08-2009, 06:37 PM
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well the gps are accurate to within feet, in comparison a MPH is not that perscise a measurement, so I would think it would give you a very accurate reprsentation. My big concern aside from knowing if I am speeding or not is that with my spedo being off, especialy reading higher then I am actualy going, It would appear as I am putting way more miles on my car then I actualy am. Being that I have less then 4,000 miles on my car, I dont want to do that at all.
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