When is the billet input shaft needed?

[2kSSLS1]

Just wondering what kind of power or what kind of times you need to be pulling to upgrade to the billet input shaft. Thanks

[chris718]

i feel comfortable saying the drum at the 11second zone and the shaft whenever locking up at wot with over 500 horsepower

[2kSSLS1]

Are we talking rwhp or fwhp? Because as of right now, Im pushing 420rwhp and thats roughly around 490 to the flywheel with my 6 speed set up. I know that I wont put as much down on the dyno because of the drivetrain loss, but I dont think that the fwhp will change. You also stated under lockup at WOT...I understand what that means, I just dont see how it relates to what we're talking about.

[jakeshoe]

2kSS,

The reason Chris states "locking up at WOT" is because once you lock the converter clutch the input shaft has ZERO give from flywheel torque to driving the trans internals.

With the converter unlocked,
the input shaft has some give on a shift, so it sees the torque load, but it doesn't see as much shock on a shift due to the converter taking some shock.

With alocked up converter the shift, as far as the input shaft is concerned, is like power shifting a manual trans. Instantaneous change of torque load.