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I'm sure most of us have seen it, but I just realized why the engine sounded like it was making so much noise....the guy was double clutching with every shift....most of them upshifts.

What's up with that? I've never done it, why would you? And that reminds me of the line in FnF when Dom says something about not double clutching right after the drag race. I still can't believe you'd want to DC during a race....

What's up with that?

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For one thing it's smoother and I'm pretty sure you can keep your revs up better that way...if you're fast at it I guess.

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Welp...it all depends on if you can do it fast or not!

If you can do it fast...then you will keep ur rpms higher...and its better for the clutch I have heard...

But...the hell with it...cuz if need be...powershift the bitch...


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Originally posted by Drew:
For one thing it's smoother and I'm pretty sure you can keep your revs up better that way...if you're fast at it I guess.

Keep in mind we are talking about upshifting. I guarantee you I am smoother and faster shifting without double clutching than I would be if I did. How do you keep your revs up better? As soon as you disengage the clutch the revs are going to match the drivetrain anyway.
 

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Originally posted by t2000gts:
what exactly is double clutching?
The idea is that you manually perform the job of the synchros.

First you push the clutch in and put the shifter in neutral.

Then you match revs with the clutch out and the shifter in neutral.

Then you push the clutch in (if you did it really perfectly, you won't need to push the clutch in, but I wouldn't count on it) and put the shifter in the appropriate gear.

If you did it correctly the the shifter will slide silky smooth into gear and the synchros will be spared wear and tear.

Double clutching slows you down on upshifts because you sit for a moment in neutral, and it doesn't spare the synchros much because they didn't have much synchronization to do, because even at a redline shift, they only have to synch a less than 3000rpm difference (equal to the drop in rpm from shifting to the next gear).

Double clutching is an advantage on downshifts, because shifting effort is greatly reduced (you can even shift into first at 20, 30, even 40mph, which is otherwise impossible) and the synchros are spared (synchros have more work to do on downshifts, because you often skip gears on a downshift, i.e. 6th to 3rd, 5th to 2nd, etc.).

And it doesn't slow down downshifts, because you should be taking the time to revmatch anyway (revmatching reduces drivetrain shock from the clutch being let out, but if you only revmatch, synchronization is still performed by the synchros).

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I actually heard that double clutching for uupshifting is good, because the turbo spools in between shifts, because the turbo can't spool when the clutch is down. I think that is why they said that in the FnF, because they were all racing turbo cars.
 

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I actually heard that double clutching for uupshifting is good, because the turbo spools in between shifts, because the turbo can't spool when the clutch is down. So if your foot is on the clutch and you are reving, the turbo won't be spooling, but if your foot is off the clutch and you rev your car, your turbo will be spooling I think that is why they said that in the FnF, because they were all racing turbo cars. I could be wrong because this is all second hand info, and I've never owned a turbo car before, so I wouldn't really know.
 

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Originally posted by ctkrider:
I actually heard that double clutching for uupshifting is good, because the turbo spools in between shifts, because the turbo can't spool when the clutch is down. So if your foot is on the clutch and you are reving, the turbo won't be spooling, but if your foot is off the clutch and you rev your car, your turbo will be spooling I think that is why they said that in the FnF, because they were all racing turbo cars. I could be wrong because this is all second hand info, and I've never owned a turbo car before, so I wouldn't really know.
Yeah, the turbo would be spooling during a double-clutched upshift. However, it wouldn't be applying any of that power to the ground, so instead of having turbo lag in the next gear, you're coasting along in neutral for a little while. So i don't see it being a benefit.

Of course, power-shifting can be a "benefit", especially because it can keep the turbo spooled on a turbo car. But I wouldn't ever risk power-shifting a car I owned (somebody else's car would be fair game <IMG SRC="http://www.newcelica.org/ubb/smilies/cwm11.gif" border=0>).
 

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eh? This is confusing. I'm almost 100% sure that there is absolutely no point to double clutching on an up shift. U double clutch on down shifts to bring the speed of the shaft in the transmission UP to the speed of the engine in the lower gear. On an upshift, when u disengage the clutch the shaft in the transmission will decelerate quickly because it has little momentum... which is a good thing! U want the shift to be spinning slower because your engine speed will be lower in the higher gear. U'd be doing your synchros a disservice by double clutching and increasing she speed of the shaft. At least that's how i understand it...

Autxr, care to put in the definitive word?

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Originally posted by dawgg:
eh? This is confusing. I'm almost 100% sure that there is absolutely no point to double clutching on an up shift. U double clutch on down shifts to bring the speed of the shaft in the transmission UP to the speed of the engine in the lower gear. On an upshift, when u disengage the clutch the shaft in the transmission will decelerate quickly because it has little momentum... which is a good thing! U want the shift to be spinning slower because your engine speed will be lower in the higher gear. U'd be doing your synchros a disservice by double clutching and increasing she speed of the shaft. At least that's how i understand it...
I second that

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Originally posted by dawgg:
eh? This is confusing. I'm almost 100% sure that there is absolutely no point to double clutching on an up shift. U double clutch on down shifts to bring the speed of the shaft in the transmission UP to the speed of the engine in the lower gear. On an upshift, when u disengage the clutch the shaft in the transmission will decelerate quickly because it has little momentum... which is a good thing! U want the shaft to be spinning slower because your engine speed will be lower in the higher gear. U'd be doing your synchros a disservice by double clutching and increasing the speed of the shaft. At least that's how i understand it...

Autxr, care to put in the definitive word?



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eh? wtf.... i responded to my own post? that's odd hehe sorry.
 

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The only real reason to double clutch when upshifting is to save your syncros. It's actually not a terrible idea.. power shifting will destroy synco gears within months instead of years. But if you feel like being nice to your brand new car, double clutching is not a bad thing. Especially if you're fast.
 
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how does double clutching when upshifting save your synchros?

and besides that, wouldn't it be faster? because, the throttle is open longer than if you got off gas. even if you put the clutch in, that brief period of time when you're engaging/disengaging clutch, throttle's wide open.

also, wouldn't it burn up the clutch? but if it does save synchros, i guess it's ok.

so would all the guys destroying their 2nd synchros from shifting like maniacs be better off double clutching? OMG, F&F taught us something! :D
 

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t2000gts said:
how does double clutching when upshifting save your synchros?

and besides that, wouldn't it be faster? because, the throttle is open longer than if you got off gas. even if you put the clutch in, that brief period of time when you're engaging/disengaging clutch, throttle's wide open.

also, wouldn't it burn up the clutch? but if it does save synchros, i guess it's ok.

so would all the guys destroying their 2nd synchros from shifting like maniacs be better off double clutching? OMG, F&F taught us something! :D
Some truckers have to double clutch every gear because they have no syncros. When you do have a bad syncro, double clutching both up and down that gear keeps it from grinding. I'm not transmission mechanic, but obviously double clutching bypasses it. As for burning up your clutch, it's possible. But honestly, I'd rather replace a clutch than a syncro ANY day.
 

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ok.. now that was confusing...

i have a pretty good understanding of downshifting and upshifting..

this is how i see it..

you only double clutch to DOWNSHIFT. because u let the clutch out to spin both the syncros and the clutch to the higher rpm so everything matches up when it goes into the lower gear..

you don't need to double clutch when you UPSHIFT because ur engine naturally descreases speed, as well as ur clutch and syncros..

to match syncros upshifting.. just put a lil pressure on ur shift knob towards the next gear and if it pops in easily with lil force.. u have matched everything and ur syncros..

when u race.. u dont' match ur syncros upshifting because u'll be losing time and ur ability to keep in VVT[L]-i ... (thats y racing ur car is bad) i do it for fun.. its y we have such a car :]

as for turbo.. i have no idea..so if its good for turbo then do it.. i'll learn it later when i get a turbo.. sounds wierd tho.. what a waste of time...

hope that helps..

::drive safe::
-Al
 
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