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hot-dog
February 17th, 2009, 04:54 AM
i went through my t/h shift tables and reworked everything to shift at the rpms i like according to throttle position. i used a speed calculator to find the mph i would need in each gear to keep the rpm shift point consistent through all the gears at all throttle positions. everything shifts consistent through the gears but at much lower speeds then i have set in the tables. when i look at the factory tables, i see that the shift points are much lower then the actual speed it shifts as well. i have my tire size set correctly in the engine and the trans tune, 285/75/16. i have also noticed that when i tune converter lockup i need to make it 5mph over the actual speed a want. so i tried adding 5pmh to the shift tables and it didn't do anything. i must be missing something, whats the deal?

vortecfcar
February 27th, 2009, 05:44 PM
If you have the relative shift pattern set how you like it, I would use the speedo correction adjustment tool located in the speedometer section of the trans tune to adjust all of your shift tables simultaneously up or down by a percentage.

It's a difficult tool to find, but is very useful.

Nick

MMLMM
February 28th, 2009, 05:33 PM
heres a thought....I'll post and see what some think before I waste my time trying :hihi:


What if I raise shift speed up high enough that it shifts a rpm and never thinks about the speed?

vortecfcar
February 28th, 2009, 07:03 PM
That type of tune is typical of the type of trans tune used by automatic cars for road racing. The idea is to always have the car in the meat of it's power band. If the truck makes 500rwhp between 2600 rpm and 3250, then set the downshift to happen only if the truck is under 2600 rpm and the upshift to happen only at 3250.

Hint: See the WOT threshold tables for an easy way to do this. Make the Allison think it's always at WOT

Nick