I ordered a gryphon and while waiting for my custom tune, I loaded up the trans tune. Well, filled up the other day with 93 and loaded the canned 93 performance tune, with custom tire setting. I put in the code recommended for 285-75-16. Now it says my truck is going way faster then what I really am. Any reason for this? I'm assuming the tuner adjusts the dash speedo and tach, b/c they are reading out identical.

Anyway, any suggestion on the what the problem is? I would like to know my true speed.

 

Did you check to see if the default gears are what you really have?

 

No, book said don't mess with the gear setting unless you have aftermarket gears. I'll double check it though this morning.

One question though. In the form I filled out to order the tuner, it ask for tire size, gears, etc.... Is this stuff suppose to be preloaded, or is that info for the custom tune I got?

 

Generally that's only for stuff you have changed to aftermarket, so that goes into the custom tunes.

Gears, though, vary from 3.55 to 3.73. Open your door and look at the sticker on the inside. Make sure you have 3.73, because that is the one that comes loaded in the canned tunes. If not, change it.

 

You need to tell Bill what gears you have so he will get them correct in the program. He used to default to 3.73, but don't know what he does now. With the canned tunes, I always had to change the setting as I have 3.55s and it defaulted to 3.73.

 

You also may not be accounting for the "squish" effect caused by weight on the tires. Unloaded, your tires have a circumference of 2619mm. If you subtract about 3% for squish (a good starting point), you should enter 2540mm. Try that and make sure your Gear Ratio is correct and you should be pretty close.

- Jack

 

K, reloaded it up. Set tires to 285 code, and gears to 3.55. Seems like it is way more accurate now. THanks for the help