speedometer calibration
Thread Starter
Safety Car
Joined: Dec 2004
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From: stafford country, va. Avatar: Me on turn 3 @ Bristol (The World's Fastest Half-Mile)
speedometer calibration
it is my understanding the the speedometers (two if you've got the hud) use an electrical connection from the top of the diff. to determine and display the speed of the vehicle.
back in the old mechanical days one could swap out the 'speedo' gear in the side of the tranny to adjust the speedo as needed.
is there any similiar adjustment one could make to the c6 ?
back in the old mechanical days one could swap out the 'speedo' gear in the side of the tranny to adjust the speedo as needed.
is there any similiar adjustment one could make to the c6 ?
Thread Starter
Safety Car
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From: stafford country, va. Avatar: Me on turn 3 @ Bristol (The World's Fastest Half-Mile)
Drifting
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From: az
hey robert, i have not gone to bed yet....hehe, the hand held predator allows you to recal in the situation of different gearing or wheel tire combo...at least that is what i remember from talking to those guys at diablosport. i would assume the hud takes the speedo reading from the same sensor, if that is the case then the hud and dash should match.
Thread Starter
Safety Car
Joined: Dec 2004
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From: stafford country, va. Avatar: Me on turn 3 @ Bristol (The World's Fastest Half-Mile)
the hand held predator allows you to recal in the situation of different gearing or wheel tire combo...at least that is what i remember from talking to those guys at diablosport. i would assume the hud takes the speedo reading from the same sensor, if that is the case then the hud and dash should match.
Drifting
Joined: Jul 2005
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From: az
Thread Starter
Safety Car
Joined: Dec 2004
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From: stafford country, va. Avatar: Me on turn 3 @ Bristol (The World's Fastest Half-Mile)
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Le Mans Master
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From: Shiloh Ohio
I put that little nervous guy (
) in the first post to demonstrate how I feel if I have to go to the dealership for service,
.
Last edited by shurite44; Jan 25, 2007 at 09:34 AM.
Thread Starter
Safety Car
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From: stafford country, va. Avatar: Me on turn 3 @ Bristol (The World's Fastest Half-Mile)
Tech Contributor
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From: St. Louis, MO
St. Jude Donor '08
Putting on 13" tires would do it. So would a bad dash cluster. I am quite sure the hud uses the same VSS (vehicle speed sensor) information as the dash cluster, I don't think there are two VSS's. There is only one thing to change for this in HP Tuners.
Changing rear gears does not require a reset of the speedo calibration. You do need to adjust shift points if you have an automatic.
If you put on smaller rear tires it will change the speedo. My drag radials show 3 mph fast on the speedo since they are about 1" smaller than my normal tires.
I think I answered questions you didn't ask here. Sorry about that.
I would always recommend HP Tuners vs. a handheld. Tuners costs less if you split the cost with the buddy and can do 100 times more things. It is not as bad to learn as people think, I can do pretty well with it now.
Changing rear gears does not require a reset of the speedo calibration. You do need to adjust shift points if you have an automatic.
If you put on smaller rear tires it will change the speedo. My drag radials show 3 mph fast on the speedo since they are about 1" smaller than my normal tires.
I think I answered questions you didn't ask here. Sorry about that.
I would always recommend HP Tuners vs. a handheld. Tuners costs less if you split the cost with the buddy and can do 100 times more things. It is not as bad to learn as people think, I can do pretty well with it now.
Thread Starter
Safety Car
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From: stafford country, va. Avatar: Me on turn 3 @ Bristol (The World's Fastest Half-Mile)
thus far it appears that it is impossible to have an inaccurate speedometer in the c6.
save for going to 1" tires
save for going to 1" tires
Race Director
Joined: Mar 2005
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From: Austin Texas
IMHO; If you change rear tire diameter the stock speedometer reading will be wrong.
CORRECTION; If you change ring and pinion the new ring gear has the reluctor for the VSS and your speedometer will be correct.
The ECM has adjustable speedo settings via tuning for tire diameter changes.
CORRECTION; If you change ring and pinion the new ring gear has the reluctor for the VSS and your speedometer will be correct.
The ECM has adjustable speedo settings via tuning for tire diameter changes.
Last edited by haljensen; Jan 26, 2007 at 09:39 PM. Reason: correct wrong statement
Tech Contributor
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From: St. Louis, MO
St. Jude Donor '08
It is also a FACT that if you change gears you DO NOT have to change the speedometer calibration. I've changed gears in 2 vettes and do my own tuning so I can verify.
Again, if an automatic, you will have to change shift points.
Race Director
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From: Austin Texas
It is a FACT that if you put on shorter or taller tires your speedometer WILL be incorrect. I verified it myself last Saturday with my Drag Radials with a buddy pacing me. 1" shorter tire = about 3 mph faster.
It is also a FACT that if you change gears you DO NOT have to change the speedometer calibration. I've changed gears in 2 vettes and do my own tuning so I can verify.
Again, if an automatic, you will have to change shift points.
It is also a FACT that if you change gears you DO NOT have to change the speedometer calibration. I've changed gears in 2 vettes and do my own tuning so I can verify.
Again, if an automatic, you will have to change shift points.
Tire diameter still requires an adjustment (or learn to live with it like I did).
Tech Contributor
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From: St. Louis, MO
St. Jude Donor '08
Joe_G; Your statement forced me to do some research and you are correct. The VSS reluctor is in the ring gear of the differential so when you change ring and pinion you are changing the signal to the VSS and your new speedometer reading is correct.
Tire diameter still requires an adjustment (or learn to live with it like I did).
Tire diameter still requires an adjustment (or learn to live with it like I did).
Thread Starter
Safety Car
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From: stafford country, va. Avatar: Me on turn 3 @ Bristol (The World's Fastest Half-Mile)
ok, direct and too the point. if i grabbed a copy of hptuners would it be possible to adjust the speedometer accuracy ? would i then be able to take it to a speedometer calibration shop and have it recalibrated ? would the shop be able to provide an official report of the inaccuracy ?
Le Mans Master
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From: Shiloh Ohio
I don't know for sure on HP tuners, but the handheld's I have seen only have a tire diameter for the speedo functions. So I don't think a handheld will help you. Some of them have rear end ratio functions also, but that is not for the speedo like mentioned above. Spinmonster uses HPtuner PM him.
