Correct tire size?

jonathanalberto007 · Post by **jonathanalberto007** » Wed Nov 04, 2009 11:51 am

Dear Friends,

I have a Predator U7193 with the latest 9r07 revision, currecntly being used on a 2004 Chevy Avalanche. A few days I go I had my tires changed to a 275/55-20 and the thing is that when I imput such numbers to the predator either by the size of 32 inches or the 275/55-20 I get my speedoto be by 3 miles off. If any one reading this can point me to the right direcction to a possible tire size that I can input that will put me close. I could have used the previous setting but according to my speedo before it was 2 over and when I did the change on the predator it gor 3 miles slow,plus also I do nor remember what I had on the tunner before, I know that it is no a big issue but it tends to get annoying. So if any one is seeing this post and has a soluiton to lie to the tunner let me know, also is there a formula that can be used to compute this? In advance thank youand your help is greatly apreciated.

pwrjnky · Post by **pwrjnky** » Wed Nov 04, 2009 2:56 pm

I'm curoius about this since I will have to change tire size as well. When the predator is first plugged into the port...do you go to change tire size first, then add the diablo tune or do you add the diablo tune, then go back and change tire size? I'm sure this will be all spelled out in the directions, but I'm waiting for it to arrive right now.

jonathanalberto007 · Post by **jonathanalberto007** » Wed Nov 04, 2009 4:08 pm

pwrjnky,

In order for it to work you must first install one of the tunes, but before it gets installed it should give you the option to modified parameters any of the parametes that you might want to modify like tire size, throttle pressure, wot, fuel table, spark,injector slope, COT, or any of the other parameters that might let you modify. But in my experience you can add the tune and change your tire size at the same time that you first install it.
I have had the tune in the truck for more than a year and haven't more than satisfied with the results.The only thing that has been an issue ever since I got it has been the dial in of the tire size because if it did not increases it decreases. I was tolod the first time what size to do, but this time wont work,don't know why, as I am 3 miles slow on GPS than on the actual speed on my speedo.

Have fun, tuning! lol

pwrjnky · Post by **pwrjnky** » Wed Nov 04, 2009 7:24 pm

jonathanalberto007 wrote:pwrjnky,

In order for it to work you must first install one of the tunes, but before it gets installed it should give you the option to modified parameters any of the parametes that you might want to modify like tire size, throttle pressure, wot, fuel table, spark,injector slope, COT, or any of the other parameters that might let you modify. But in my experience you can add the tune and change your tire size at the same time that you first install it.
I have had the tune in the truck for more than a year and haven't more than satisfied with the results.The only thing that has been an issue ever since I got it has been the dial in of the tire size because if it did not increases it decreases. I was tolod the first time what size to do, but this time wont work,don't know why, as I am 3 miles slow on GPS than on the actual speed on my speedo.

Have fun, tuning! lol

got it! I recieved it earlier and it let me adjust the parameters just before the tune install. Thanks. MAJOR DIFFERENCE!!!!

Scooter88 · Post by **Scooter88** » Wed Nov 04, 2009 7:25 pm

Hey check this link out..i had similiar prob but turned out this was the issue..

http://www.diablosport.com/index.php?na ... ic&t=17736

jonathanalberto007 · Post by **jonathanalberto007** » Thu Nov 05, 2009 1:48 pm

Thank you scooter88, I seen that thread before, but you mention that with that crom file you were able to adjust for some parameters that were not working? including your tire size and injector slope?

Scooter88 · Post by **Scooter88** » Thu Nov 05, 2009 5:58 pm

jonathanalberto007 wrote:Thank you scooter88, I seen that thread before, but you mention that with that crom file you were able to adjust for some parameters that were not working? including your tire size and injector slope?

Yeah it seems the basic tune was writing but was not able to adjust anything including the tire size. If your able to get your injector slope dialed in,then maybe this wouldnt fix it. Johan or mike should be able to help...