Speedometer Calibrator

[hobbsrt]

I have been struggling with calibrating my speedometer. I have a 2001 gmc 2500 hd 6.0L with 37" tires and 5.38 gearing. I tried the Hypertech unit and it wouldn't go past 34" tires and I don't remember the gearing even though it said it was customizible. I returned that unit and talked to 4 wheel parts show said the even more expensive Superchip Flash Paq would work and although it accepted the 37" tires it would only take 4.88 gearing. I tried that setting and the speedo is still off by 15% or so. Is there a way to get this properly calibrated? I am thinking of just going to the dealer. Ideas?

 

[tennesseewj]

Have you considered a custom tune from Black Bear Performance or similar? They should be able to write a program specific to your rig (and tire size).

Sent from my Pixel 2 using Tapatalk

 

[hobbsrt]

I have not. That's a real good idea. Thank you.

 

[hobbsrt]

Boy that's expensive.....

 

[Pacific Northwest yetti]

I have a BullyDog GT for my 6.0, https://www.bullydog.com/products/b...MakeId=2&vehicleModelId=41&vehicleEngineId=26

It let me calibrate gearing for 4:88 and tires of 33, but never tried more than that. And its usually right on, but will loose 1-2mph as the tires wear.

I had a Hypertech, and hated it. only had problems with it.

I like my Bullydog, but it was spendy- and for our year of trucks is a pain to set up ( have to pull a few fuses, and relays ) each time you want to change your tune. Other than that I have been happy with it, call them and see what the upper and lower parameters of gears and tires are.

otherwise, BlackBear may be your only option. Our local dealer wont custom program of FLASH anything out of stock.

 

[rayra]

Shouldn't be more than an hour's billing rate at any shop with the equipment. AAA used to have a roving service that would travel to each AAA office and calibrate Members' vehicles, not sure if they still do in this age of CANBUS.
FREE app TorqueLite will show you your GPS speed on your smartphone or tablet.

 

[hobbsrt]

Thanks guys. I do have torque and yes it shows speed, so does my gps and another app that I have, that's how I know its off. I am going to call the dealer and see what they say. If they cant do it then I will try the others. btw I love the torque app.

 

[hobbsrt]

the other thing I am actually more concerned about is the Odometer.

 

[hobbsrt]

I found a tuner that works! I bought the edge CS2 tuner and it accepts up to 5.56 gears and I think 44" tires, maybe 40, I didn't look that far. After a few calls to tech support, uploading the stock program and pulling the dash to get at the radio harness and then pulling some fuses it seems to be within about 1-2 mph. Good enough for me. I think my gps isn't a very good speedo but the other app I have is pretty close.

Thanks for everyone's help. Cheers.