Power shifting and clutchless shifting- what's it all about?

[AllanS]

I've been hearing about power shifting and clutchless shifting, and while I understand the basics of clutchless shifting, at what rpms/situations is it feasible, and why would I want to use it instead of using the clutch?

Power shifting, I understand to simply mean shifting at the redline.. is that right?

Thanks!

AllanS
91' 535iM

[darthmaul]

oh yeah...and you might want to ask/explain DOUBLE-CLUTCHING

[Paul in NZ]

my understanding of power shifting is when you shift with the clutch but do not take your foot of the throttle....ouch....cluthless is shifting without the clutch and i guess the throttle mode is your choice.rally cars f1 cars and motorcycles can handle these modes of shifting much better than our assemblies but they are built to do so

[Rory]

I've been hearing about power shifting and clutchless shifting, and while I understand the basics of clutchless shifting, at what rpms/situations is it feasible, and why would I want to use it instead of using the clutch?

Power shifting, I understand to simply mean shifting at the redline.. is that right?

Thanks!

AllanS
91' 535iM

Allan,

The good engineers at BMW put the clutch there for a reason so I recommend using it You are only going to put some added wear and tear on the car by doing so. If you want to learn a good technique,double clutching is the way to go and will save your Synchro's and tranny. Now if you dropped a V8 in that 5 of yours and are heading to the drag strip we can talk about powershifting, otherwise just stick with the clutch.

Best,
Rory

[Mr Project]

Power shifting was mentioned earlier... basically you shift quickly (using the clutch) without letting off the accellerator. You need to start the shift before redline, obviously, if you don't want to over-rev the engine. Drag racers will do this in some cars to preserve the flywheel inertia and give a little accellerative 'boost' when the clutch slips to match the revs of the engine to the car. Very hard on the clutch, and can be hard on the engine if over-revved. Plus, it's easy to mash the gearbox since you're nervous and in a hurry.

No real use outside of drag racing AFAIK.

Clutchless shifting is a nice skill to have if your clutch goes out and you have to drive the car home. Other than that, I can't think of a situation where it would be a real benefit. It is just what it sounds like, you lift the throttle, pull the car out of gear, match the revs to the next gear, and gently shove the tranny into the next gear (up or down), without ever touching the clutch. I used to do this on my old RX-7 just for fun, since I didn't care about the tranny. Obviously, this can be REALLY hard on the tranny and to a lesser extent, the engine.

[Unregistered]

I've been hearing about power shifting and clutchless shifting, and while I understand the basics of clutchless shifting, at what rpms/situations is it feasible, and why would I want to use it instead of using the clutch?

Power shifting, I understand to simply mean shifting at the redline.. is that right?

Thanks!

AllanS
91' 535iM

I agree with the last post. Have had clutch cables break in various vehicles over time and the clutcjless shift is required then to return to base. Don't know why anyone would want to do it otherwise when the manufacturer clearly expenses the clutch as part of the vehicle. Just me.

Paul

[AllanS]

Oh, I'd never do it myself, but I heard people talking about it as if it was something common. I'm very keen on matching revs precisely, and putting as little wear on the clutch as possible, in order to postpone having to install a new one.

[AllanS]

So there's really no purpose outside of a racetrack for using both methods, unless the clutch pedal failed or something- very good.

[dave b]

shifting when my clutch hydraulics were shot. Basically, he revved it in neutral, then slowly feathered the gearshift until he matched the revs (he did it when they were dropping). Not something I would try on my own, even though it would have saved the time for the tow.

[Paul in NZ]

and if done properly is hardly noticeable..the hardest thing about having no clutch is starting off again....