has anyone played with shift timing?

[sledbert]

Has anyone played with the B5100, 5104, 5108 etc "desired shift timing" tables?
I have built an ECU tune that tows good & pulls like a !*%$&@ at WOT.
Now I would like to tighten up the shift firmness & remove the slush box feeling.
It looks like simply changing the -100 # to say -150 or-200 ??

2008 LMM 6spd
thanks guys

[cmitchell17]

Ive heard its only tuning the shift timing for the oncoming clutch and that it won't have that much of a diffrerence, but I don't see why you couldnt go a little.

[sledbert]

Judging from what EFI has for a description, it looks like these are the lengths of time that the solenoids take to apply/release the clutches in order to shift to/from the next gear.
So..... yeah, it looks like we should be able to make adjustments to the values, the only negative could be a harsh shift.
??

[cmitchell17]

I don't know anything about transmissions but ive seen where people have made tcm tunes and adjusted the shift times by about 50-250ms. I tried adjusting mine in the 70+tps area by about 25-150ms and on I think the 2-3rd shift it does something wierd. So im going to change them back to stock for now.

[sledbert]

thanks, goood to know. I have asked the same question on another forum, I will let you know if I get a response.

[Sparky8370]

I adjusted mine. It seemed to make it feel better without being too harsh. I didn't adjust it too much. You can find my stock tune as well as my modified tune on www.dieseltowingresource.com

[cmitchell17]

Has anybody ever adjusted the TCC duty cycle past where it was stock? What if you made it 100% could you get a little more holding power out of it?

What about disabeling the g-soleniod at a diffrerent rpm? Ive heard the g solenoid lowers the main pressure at low throttle so if you disabled it at a lower rpm it would build more pressure faster?

[Cougar281]

Has anybody ever adjusted the TCC duty cycle past where it was stock? What if you made it 100% could you get a little more holding power out of it?

What about disabeling the g-soleniod at a diffrerent rpm? Ive heard the g solenoid lowers the main pressure at low throttle so if you disabled it at a lower rpm it would build more pressure faster?

You don't want to put the TCC DC to 100%; You'll burn it out because it's not rated for that duty cycle.

[cmitchell17]

Ok thanks, can a soleniod never be at 100%? Is there any benifit to disable the G Soleniod at a lower rpm?

[Cougar281]

Ok thanks, can a soleniod never be at 100%? Is there any benifit to disable the G Soleniod at a lower rpm?

Depends on the solenoid. The TCC one isn't rated for 100%; not sure what the others are. I THINK the G-Sol was put there to get an extra .00000001 MPG for the EPA; I don't think it hurts either way (enabled or disabled).