From my understanding, powershifting is shifting without using the clutch, waiting for just the perfect time just before the redline and then jam it into the next gear. I THINK double clutching is pushing the clutch to get it out of the gear then releasing and pushing again to put it into the next gear. My friend has to do that with his camaro cause sometimes it won't go into the next gear. He calls it double clutching but I don't know if that's what it really is.

 

OK.

Powershifting is keeping the gas down as you shift, as Urban said.

Double clutching is 1) clutch, put car in neutral; 2) hit gas to give engine some juice; 3) clutch, put car in gear.

I don't know if there's a name for shifting without clutching. Perhaps "bad idea, will destroy tranny if you screw up."

 

lol thats wut i was thinking..how would u shift without pressing on the clutch

 

Here is a definition for double clutching...and related heel-to-toe. Some people just call heel-to-toe "double clutching." Basically, Double clutching is matching speeds. let me know if this helps/hurts.

http://encyclopedia.thefreedictionar...ouble%20clutch

 

aight, shifting without the clutch will not hurt the tranny. its what the synchros are there for. you would basically only do it while driving around town and NOT getting on it at all. all you do is get to the desired speed, let off the gas, then gently pull the shifter out of gear and push into the next gear.

double clutching is a downshifting technique. you use it to take some strain off the tranny itself. i use it ALL the time and it makes driving a lot more fun and interesting. to do this, just depress the clutch when youre ready to downshift and shift to neutral, let off the clutch, kinda blip the gas pedal so the rpms jump to what they will be at when its in the lower gear, then depress the clutch and shift into the lower gear. its kinda hard to get use to this but its just something you will get a feel for once youre "in tune" with your car.

and about the power shifting. i have NOT been able to do this, EVER. the rpms just rev too quickly in this car. it may be that im shifting too high, but i dont see any gain from doing this if you have to shift at such a low rpm level.

 

thanks, now tell me if I was at least correct on the definition of power shifting!

 

I'll clean up on the shift point thread and make a cohesive write-up. Then I'll take on other topics.

 

Petey, Im not a tranny guru--BUT, not using the clutch requires that the syncros speed up or slow down a heavier mass due to the driveline being engaged, hence stresing the syncros much more than usual. Im on my 3rd box with new syncros because just such driving to save my clutch. Dont do it, it'll save the tranny.

 

If you revmatch perfectly, the synchro does have to do anything. The flywheel speed is already matching to the wheel speed. There is no speed difference. You will be able to shift clutchless.

To upshift, you lift off the throttle slightly and pull out of gear into neutral. Then you revmatch in neutral. Then you shift into gear. If you spin the engine just right, you'll be able to shift into gear without resistance.

But if you don't do it just right, you'll destroy the synchro instantaneously. The synchro is designed to equalise the layshaft speed to the driveshaft speed. It's not meant to take the rotating mass of the engine on top of that.

Using the clutch is mechanical sympathy. You can get by without a clutch, but you'll have to rebuild your gearbox every day

 

but you shouldnt have to revmatch if your upshifting, should you? i only do it when im just cruizin around town. when i shift, theres only a loss of 500-700 rpm so i dont really see much of a strain being put on the synchros.

 

Ideally, you should revmatch everywhere. It makes for a rough shift if you don't.

I don't think you understand the definition of revmatching.

 

yes, i do believe that. but how are you suposed to revmatch if your upshifting? all it will do is give you a jolt when you get it into gear.

 

Like I said, you don't understand revmatching. Let me explain it, again...

Revmatching is defined as matching the engine speed to the wheel speed when you engae the clutch. It doesn't matter if it's an upshift or a downshift. You have to make sure that the engine is spinning at a speed that matches to the road speed when the clutch is engaged.

For example, when I'm ogoing 25 mph in 2nd gear, I would be revving about 3,000 RPM or so.

So let's say I accelerate in 1st up to 25 mph, then I want to shift to 2nd. I would push the clutch in and select 2nd gear like normal. The car is now coasting at 25 mph. But when I let the clutch out, I have to be sure that the engine is spinning exactly 3,000 RPM. If I hold the engine too high, the car would jerk forward. If I hold the engine too low, the car bog and jacknife.

So you see, you should be revving 3,000 RPM when you let the clutch out. If you get it just right, you can dump the clutch and you won't feel a thing.


Likewise, say I'm going in 3rd gear at 25 mph. I want to shift down to 2nd. Same deal. I push the clutch in and select 2nd. The car is now coasting at 25 mph. When I let the clutch out, the engine will catch the clutch, which catches the gear, which catches the driveshaft, which catches the wheels turning 25 mph. I have to make sure I'm revving 3,000 RPM when I let the clutch out to make it a smooth shift.

So you see, you should be revmatching every time you shift, no matter if it's up or down. What you're describing is blipping the gas on the downshift to revmatch. When you shift down, you have to rev up. When you shift up, you have to let the revs drop and hold it at the revmatching point when you release the clutch.

That's it. Not more to it.

In practise, though, it's really an imprecise art. You do what you can, and you let the clutch slip and equalise the speed difference.

If you can dump the clutch and doesn't feel the car jerk or see the tachometer bounce, you're doing it right. Either that, or you're in neutral

 

powershifting is gas on full down, clutch real fast and change the gear super fast so there is no momentary paulse between shifting.

you'll need a good clutch for that, since our stock clutch wont let us powershift...

hi.

 

i used to work for a construction company that i drove trucks for. with 7 forward gears we would "powershift" the hell out of them. no clutch, just shift. it worked to if you did it fast enough. my company had to foot the bill for a new tranny in that thing. we saved them some money though, and me and a buddy put it in ourselves. lol