Norm Peterson

"Feathering" the clutch is nothing more than allowing it to slip. It's probably impossible to avoid this happening at least a tiny bit with a street or street/strip clutch whose disc has a marcel, but this method should not be deliberately and consciously used once you've got the car rolling. It does create extra heat and wear from the sliding friction.

About the only way I can put it is that once you to learn to match the revs and get your timing down, you can get clean upshifts without causing a lot of impact loading. The marcel and the springs in streetable clutch discs will reduce the severity of the impact somewhat (that's what they're supposed to do), but these can be "bottommed out" on a harsh shift, which sends the impact way up again. Yes, relatively "softer" clutch engagement will cost you slightly in a drag race.

Powershifting does more than speed up the shift time. It converts the rotational momentum of the flywheel/pressure plate/balancer/crankshaft into a very brief torque "spike". For a tenth of a second or three as the engine rpm drops from 6000 (or whatever) down to 4000-ish, you may be getting 400+ ft-lbs going into the transmission from an engine that only puts out 300. After that, it's back to 300 (or whatever).


Norm

Shadow7874

Normally when i launch i drop the clutch and then gas it. Ive never launched while holding the car over 2k. I never break loose and always have bad lag, but soon as its rolling it takes off with out traction loss. And i would think it would be the best method as far as clutch wear because its already engaged by the time it gets the full gas

AmericanSpeed

sorry for the lack of clarity, I powershifted at the track for about 100 passes before the synchros crapped out.

Norm Peterson

OK.

That's about 100 fatigue cycles on the 2nd gear synchros and 3rd/4th synchro rings, 50 on the 3/4 hub . . . doesn't suggest that any huge strides have been made in the last 40 years as far as OE regular production durability goes . . .

Speed costs money, or something like that.


Norm

06stangGT

thanks for the input guys

AmericanMuscle4.6GT

actual powershifting? like no lift shift?
i've done probably 200 ***** to the wall 1-2 shifts (LIFTING OFF THROTTLE, but very briefly)........here's what it sounds like: http://www.youtube.com/watch?v=4f4lva3SP1Q

(don't mind the slow 2-3 shift =/ )

but yea, AmericanSpeed what were your symptoms of crapped out synchros?? describe in detail plz? i'm worried about mine.

POWERSHIFTING on a TR-3650 will result in TOASTED SYNCHROS if done repeatedly. don't do it. you don't need to.









BTW AmericanSpeed i managed a 12.883 @ 106.58 with just a cai/tune.........and drag radials haha

Riptide

That 2-3 was slow? Seemed ok to me.

AmericanMuscle4.6GT

lol well thanks.........i'll upload an exterior video of me doing a good 2-3 upshift and you'll understand what i mean haha

AmericanSpeed

Once the throttle hit the floor on my run after luanch, it stayed there. I also only pressed the clutch in just enough to slam into the next gear. Never had to shift to 4th with the 3.55 gears, had the rev limitor set to 6900 and would cross just before hitting it.

I knew my synchro was gone because I couldn't shift into 3rd gear, LOL. It would just grind like crazy and not go into gear, so I just drove it home and then to the shop shifting from 2nd to 4th.

Shadow7874

So is there a right way to shift at peak RPM that wont damage your car as bad yet still be quick?