going to dyno next week, gonna compare stock and some tunes

so locked or unlocked t/c and why?
how to unlock, touch brake or do with hpt, i don't know it you can do that live with hpt or do need to put it in the tune, if so where?

thanx

 

bump.. I was wondering this myself.

 

I believe you can do it with EFILive with the bi-directional controls, but I have been told you lose resolution on the scaner (frames per-second). Does HP Tuners have bi-directional controls?

 

Yes Hp Tuners has what they call VCM controls were you can lock or unlock the TC (among other things). Probably works just like EFI in that you will lose some resolution in scanning by using the controls.

 

My tuner thinks that while we were dynoing my truck the last time, that hp tuners automatically locks the converter for you when your doing a WOT pull... Is he wrong, does he manually have change it to get it to lock-up? Is it something you do during the pull or change it before hand?

 

If you tune is setup to lock the TC in 3rd at WOT then he would be correct...

 

I would agree there. It should have nothing to do with the software that is used only how the tune is written. If the trans. is tuned to lock at a whatever speed in 3rd then that is what it will do.

 

What difference does it make with the dyno #s? Like is 400rwhp with the converter locked different than 400rwhp unlocked?

 

If the converter is unlocked there will be hp lost to heat in the converter since it is slipping.

 

If it is a stock converter, you will see very little gain from locking up the TCC clutch. Stock will usually show about 5rwhp increase, unlock to locked comparison. Also, do not lock the TCC too much on a stock unit, the TCC lining GM uses is strictly designed to be soft and very unoticeable, not for holding WOT power. If you have an aftermarket converter, with a stock style TCC you really shouldn't attempt this more then once on the dyno. Only enlarged, multi disc converter can endure this abuse without an issue. You can identify these converter by the billet front cover (the part that bolts to the flexplate). With aftermarket units, you can see anywhere from 10-50rwhp gain going from unlocked to locked. The reason to do locked TCC runs on a dyno is for bragging rights, or to compare to manual dyno graphs and nothing more. Since an auto always performs unlocked at the strip, there is no need for autos to lock the TCC during dyno session. Good luck!