LS1Silverado05

iTrader: (41)

Was listening to some typical M6 vs A4 Bench racing the other day, and the whole "M6 will pull harder down track and trap higher".....and it got me to wondering, does anyone come out of the hole under converter and lock it as soon as possible and leave it locked for the entire run? I would assume a much greater trap but still a 60' typical of a stalled auto....

Does anyone do this, and if not...why not? Is there too high a drop in RPM with it locked between gears? Just not reliable?... Thoughts?

01ws666

I've only heard of people locking them mid 3rd under wot and yea it will gain you a couple mph from what i've read. idk about locking it earlier then that but i do know if its locked durring a shift bad things will happen...

LS1Silverado05

iTrader: (41)

Is that because you cant lock it through shifts on a mechanical level or because the parts are too weak to handle it? Is it a function of part strength or mechanically impossible to achieve reliably?

Also... will it net any significant ET drop or simply a MPH gain?

01ws666

Its because the parts are too weak to handle it reliably...

For your 2nd question I've never tried it so any answer i gave would only be speculation, maybe someone who has can throw their .02 in cuz I'm curious also...

jimmyblue

iTrader: (11)

If you ever do a locked vs unlocked, MPH vs time log
you will see that unlocked is way better (provided your
converter is any kind of efficient) until the converter
has hit its coupling plateau and quits multiplying torque.
On mine, that is about 5500+ RPM. With converter
locked you will be pulled down to lower than that, and
lose acceleration. Only lock if you are upshifting right
before the traps (if 1/4 mile is your thing). Anything
else just costs you performance, wear and possibly
suffering.

Forget calculations and theories, if you don't have all
the facts and formulae. And in this area, those are
hard to come by. But you can force lockup in the scan
tool bidirectional controls, do a third gear pull and see
for yourself.

spy2520

iTrader: (3)

There is a lexus with a 7 or 8 speed trans that locks in 2nd gear under normal operation. Helps on gas I guess, like what was already mentioned I think there are only a few instances where it would help, probably just slow you down.

LS1Silverado05

iTrader: (41)

Thanks for insight. Makes sense to me now.

01ssreda4

iTrader: (96)

In order to lock under WOT and not tear your **** up you need a converter designed to do that. Otherwise you are asking for trouble. Trans cant take WOT shifts without the converter as a cushion bc they arent designed for that. Converters have shift extensions that allow you to retain rpm during a run making your car faster, you wouldnt want to take that away. So locking up on the big end with a triple disk converter in the last gear would be beneficial.