tune settings

[airdahl]

Can anyone help me with a little advice? I have read that it is wise to set the rear axle ratio and the revs per mile so my truck will shift right. I shifts like crap now. I have as stock 2006 super duty with one size over stock tires (285/70R17 tires) not to sure what these tires are in inches? I am running spartan and the canned tunes on my SCT X3 right now.

[tech10002]

Use this to calculate your revs/mile. Tire Calculator

You can find the axle ratio on a tag on your rear end. It will say something like 3L73. That would be a 3.73 limited slip. Most F-250s and SRW F-350s have 3.73s. If you want to adjust the shift firmness, that's in the menus too. Just make sure you don't touch the WOT settings. Try turning it up or down 10-20% or so at a time, reflash the truck, and see how you like it.

[Raul@Stealth Automotive]

you dont need to do that.... you wont find an axle ratio that is perfect for 1 size over stock... i only recommend it for tires over 35"

i would try some better tuning.. get some custom tunes and your trans will work fine...

-Raul

[npccpartsman]

Axle ratio and rev's per mile are two different settings. Axle ratio can be set perfectly, but rev's per mile has to be calculated, however it can only be set to within 5 of actual.

FWIW---all tire manufacturers are a little different on tire height even on the same size tires. Also remember that as your tires wear you'll get more rev's per mile due to smaller diameter which is why that setting is only by 5's in the SCT. NOT extremely critical for shifting

[tech10002]

Originally Posted by Raul@Stealth Automotive

you dont need to do that.... you wont find an axle ratio that is perfect for 1 size over stock... i only recommend it for tires over 35"

i would try some better tuning.. get some custom tunes and your trans will work fine...

-Raul

I think he was talking about setting the axle ratio in his SCT rather than swapping the gears. With his 70% aspect ratio on slightly wider tires, his rolling diameter is almost identical to what my stock size 18s are anyway.

[Raul@Stealth Automotive]

Originally Posted by tech10002

I think he was talking about setting the axle ratio in his SCT rather than swapping the gears. With his 70% aspect ratio on slightly wider tires, his rolling diameter is almost identical to what my stock size 18s are anyway.

ah k... i assumed he was gonna change out the gears

[airdahl]

i was looking at how to set the axle ratio and revs per mile and what the numbers were for my truck.

[Dave]

Originally Posted by airdahl

i was looking at how to set the axle ratio and revs per mile and what the numbers were for my truck.

Did you get it figured out last night?