Shifting Question

[hemi_fan]

Hey guys, ive read a lot about people Power Shifting, how exacly is it done? Is it with no clutch?? I know all about double clutching and heel toe, but im not familiar with this type of shifting. Any explanation would be great.

[ChrisAW11]

You stay full on the throttle while shifting, but you use the clutch (at least a bit) to reduce the stress to the drivetrain a bit. Of course you try to do it as quickly as possible.

[nthfinity]

^^^^^^
almost/mostly what he said...

rather then full throttle, proceed to keep the revs above where they would drop down to at the same velocity in the next higher gear, then apply throttle pressure before the gear is locking in......
you actually get a variable power output during this

[hemi_fan]

Oh, i understand

That sounds pretty risky for me to try, since Im not a very fast shifter, and i have no rev-limiter, i have a chance of over-revving it if i miss the gear or shift too slowly, so i think i'll stick to granny shifting like i do now. lol

[crsbarnard]

Will this be very hard on a normal street transmission?

[nejcdolinsek]

Originally Posted by crsbarnard Will this be very hard on a normal street transmission?

If you do it too much, or if you f$%k up, I don't think its very "car friendly", if you know what I mean

[nthfinity]

its not for having a trans you want to have last 150,000 +miles
and of course, race cars have transmission swaps sometimes in race progress.

having a better clutch will reduce wear, such as a metalic racing clutch plate, or some semi-exotic carbon kevlar clutch.

the synchro mesh is also damaged a wee bit. for example, my old saab's previous owner was either terrible at shifting, or had been quite hard on the transmission, and the second gear synchro teeth had locked in.... 1600$ later it was working like new.... thats when i decided i could be hard on it lol

a lot of shifting is having the right feel. this may be the fastest way, and takes a little practice to not bog the engine down to much during shifts; its much easier, and beneficial then 'dubble clutching'

i dont think powershifting is that dificult, and wihtout a person to show directly how to do it, i i think would take an afternoon drive to figure out if you know how its done, but just havent done it yet.
a tach definately would help.

[coombsie66]

Surely having a clutch with less slip would increase the instantaneous stresses being passed through your drivetrain, if you flat shift.
Having a little clutchslip gives a bit more clutchwear but saves your transmission, unfortunately it 'blues' your flywheel friction plate too.
I flat shift when im racing, but thats rare, and i think that the stress i save the transmission by accurately rev matching on the downshifts, and heel and teoing more than accounts for a little misbehaving!

[RC45]

And once your power gets into the 400hp+ range you can begin sheering torque, tubes and drive shafts if the clutch grips instantaneously...

[nthfinity]

And once your power gets into the 400hp+ range you can begin sheering torque, tubes and drive shafts if the clutch grips instantaneously...

oh if i only had 400 hp

yes, i neglected to remark on the aspect of the inertial energy being transfered elsewhere, well said coombsie. relating to that, the guy i know with a 95 ZR-1 (13,000 miles) drives qiute hard everytime hes on the road... and although the car has qiute low miles, he just had to get his flywheel replaced @ 3800$ usd.

[coombsie66]

Originally Posted by RC45 And once your power gets into the 400hp+ range you can begin sheering torque, tubes and drive shafts if the clutch grips instantaneously...

If i knew the driveshaft dimensions, and the material properties, i could calculate the torque needed to shear it. One good thing from the shitty solid mechanics revision ive just suffered with for the last few weeks!

[RC45]

I also meant to add... "with sticky tyres" to my initial remark...

[saadie]

i also dont have a Rev meter ... i judge the revs by the sound of the engine .. ma engine is really noisey .. lol .....

and yah yer stick willl come in yer hands if ya dont dont press the clutch .....

[coombsie66]

"yer stick will come in your hands", thats up to you mate, aint got anything to do with the clutch!

[hemi_fan]

when you rev-match properly, when you release the clutch, you wont hear any RPM change in the engine, correct? I want to learn how to do it. It would be awesome to be good at, like touch typing i guess... the more u practice, the easier it becomes.