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Discussion Starter · #1 ·
ok heres the deal i bought my car a yr ago and they told me there was a 373 gears in it so i bought the sct xcal went to my local speed shop and the speed is still off so we programed it for 410 and im still 7 mph off i no this because i have a speed deal by my house u know the ones the cops put out on the parking but anyway u think it has 355s in it i quess what im asking is how the hell can u tell or fix this my car is an automatic
 

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Do you have aftermarket gauges? Maybe they effed up the needle while changing them?
 

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Get a friend to drive beside you on the interstate and talk to him about what speed his odometer says, and compare it to yours.
 

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Discussion Starter · #4 ·
yes but when i go pass the radar im 7mph off say my speed on the dash say 30 but radar says 23
 

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tire size along with gears...maybe a mix of both??
 

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Discussion Starter · #6 ·
its all programed in sct xcal
 

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Discussion Starter · #8 ·
i dont know what up it drives like a race car plenty of power shifts good ill have go deeper in it ill get to the bottom of this some how all the help i can get will be helpfull
 

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Maybe the radar thing is messed up *fingers crossed*
yea maybe the radar thing is messed up and not your car :confused:

police equipment is a little :eek: sometimes
 

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Take your roomies car through it and check the police speed checker. I'd think 1-2mph off max with those things.
 

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have you tried a 4.30 gear tune?? you'd know if you had them im sure, but its also worth a shot
 

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Discussion Starter · #13 ·
ya i will try that thanks
 

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ok heres the deal i bought my car a yr ago and they told me there was a 373 gears in it so i bought the sct xcal went to my local speed shop and the speed is still off so we programed it for 410 and im still 7 mph off i no this because i have a speed deal by my house u know the ones the cops put out on the parking but anyway u think it has 355s in it i quess what im asking is how the hell can u tell or fix this my car is an automatic
I haven't done this,but I jacked mine up and found this... of course if your gears are not stock you'll need the tuner or a gear box.

1999-2004 Calibration Process

To find out your gear Ratio: (thanks to Rick @ CJ Pony)

"Calculating the gear ratio is pretty easy. Jack up the rear with both wheels off the ground. Rotate the tires 1 time and count the driveshaft revolutions. If the driveshaft turns a little of 4 times then you have 4.10 gears. If the driveshaft turns about 3.25 times then you have the stock 3.27 gears."
 

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Check it against somebody's GPS thing
 

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+1 GPS...most of the police speed radar signs I see by me are all ridiculously off. I've compared my vehicle GPS, handheld GPS, speedometer are all almost dead-on with each other, so the signs are off. My guess is since they are not using them to pull people over, they are probably not calibrated frequently.
 

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+2 on the GPS. that is one of the most reliable things to do. if you dont have one, resort to the friend driving beside you. if you find its still off then you can work from there, but dont use those radar things to "guess" your speed. those things are f**ked from the get go
 

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Yep, they set them so they say your going slower then you really are.. then you speed up thinking your speedo is off.. then they give you tickets :yes
 
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