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Quick question about "rev-matching" and wearing on the clutch.

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Old 06-16-2007, 08:17 AM
  #41  
Kolia
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These "How to shift" discussions are always entertaining... Lol

Double clutching on upshifts? Why? TO speed up the synchros of the lower gear? It's already spining faster than necessary whenever a higher gear is selected... I think it's a waste of time and a potential risk/wear of engaging a synchro while spinning way faster than it would have on a "normal" upshift.

On downshifts, it's usually not necessary, but I do it all the time. Simply because it's better when I'm at the track and I need to skip a few gears. In these moments, I need the gear to get in smoothly with a positive engagement. The regular double clutch downshift trainning pays off then.

In any cases, just drive. Keep your foot OFF the clutch pedal as much as possible and have fun.
Old 06-16-2007, 09:15 AM
  #42  
bailey bill
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Amazing!!!

I've been drving manual trannies for over 50 years, and I never know it was so complicated.

And I never knew clutches and trannies were so fragile. I have abused both pretty badly at times, (showing off, racing, pulling trailers, etc) so I can't understand why I have never broken or worn out either one.

bill

Last edited by bailey bill; 06-16-2007 at 09:17 AM.
Old 06-16-2007, 09:48 AM
  #43  
FALLEN1z
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guys this really isnt complicated, it's simple physics and an understanding of the clutch and the internal workings of a transmission. you dont need to double clutch anymore, you can but it isnt necesary.

and one final point to make about rev matching and how it's a GOOD thing to do is this....

on my last z i bought it and it had a blown third gear synchro (blown when i bought it, i had nothing to do with it), if i downshifted by just putting the clutch in and tried to put it into third it would grind like crazy every time and refuse to go into gear......if i rev matched, it went right in with NO grind and NO hesitation....and that was with no synchro to speak of, so try and tell me that rev matching hurts synchros or your clutch
Old 06-16-2007, 11:28 AM
  #44  
roast
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These threads are indeed amusing. Talk about the blind leading the blind.
Old 06-16-2007, 01:42 PM
  #45  
Korki Buchek
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It's because people are talking about 8 different things when they say rev-match or double-clutch or even downshift. But, I'm done with the discussion so have at it.

http://en.wikipedia.org/wiki/Double_clutch

Last edited by Korki Buchek; 06-16-2007 at 01:46 PM.
Old 06-16-2007, 03:54 PM
  #46  
roast
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Originally Posted by Korki Buchek
It's because people are talking about 8 different things when they say rev-match or double-clutch or even downshift. But, I'm done with the discussion so have at it.

http://en.wikipedia.org/wiki/Double_clutch
Even your wikipedia article is wrong. I think you should have been done with this discussion before you started.
Old 06-16-2007, 04:11 PM
  #47  
Kolia
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Originally Posted by Korki Buchek
It's because people are talking about 8 different things when they say rev-match or double-clutch or even downshift. But, I'm done with the discussion so have at it.

http://en.wikipedia.org/wiki/Double_clutch

Oups. Again, no double clutch is needed when upshifting, even on a synchroless gear box.
Old 06-16-2007, 04:26 PM
  #48  
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Originally Posted by wikipedia
The purpose of the double-clutch technique is to match the rotational speed of the input shaft being driven by the engine to the rotational speed of the gear you wish to select (directly connected to rotating wheels).
I got a kick out of the wikipedia article. I think korki wrote it.
Old 06-16-2007, 04:40 PM
  #49  
Korki Buchek
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By double clutch, what do you mean?

Also, it is not necessary on a synchroless gear box because you can just hold the clutch down until the RPM's drop. But I prefer not to hold the clutch down while that happens.

Also, even w/ synchros, double clutch prevents the car from jerking forward when you upshift at moderate-high RPM. The same can be accomplished by holding in the clutch.

KB [Learned to drive on a '69 Ford Truck w/ a synchroless gear box]

Last edited by Korki Buchek; 06-16-2007 at 04:44 PM.
Old 06-16-2007, 06:19 PM
  #50  
Kolia
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Jerking on upshifts ? The only way that can happen is if the engine rpm's are out of synch by a fairly large margin. That has nothing to do with the transmission operation. Synchro or not, no matter how many time you hit the clutch before getting in your gear, if your revs aren't right, you'll jerk the car.

Double clutching, like you said somewhere, is used to accelerate the next gear's synchro. When you upshift, you need to deccelerate the lower gear's synchro. No double clutching is necessary or usefull then as it's already spinning too fast.

If your truck needed some double clutch on upshift, I suspect something was badly worn/broken in there.

I've driven synchro-less cars too.
Old 06-16-2007, 06:56 PM
  #51  
Korki Buchek
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We are talking about different things by "double clutching."

I mean placing the transmission in neutral. Allowing the engine speed to drop. Then reengaging the transmission in a higher gear.

For example: If i want to shift from 2nd to 3d, I'll push the clutch in and disengage the transmission, then let the clutch out. Let the engine speed drop by a few RPMS, and then push the clutch in to reengage the transmission.

I don't mean increasing the speed of the synchro in the higher gear. You couldn't do that if you wanted to.
Old 06-16-2007, 07:05 PM
  #52  
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Aaah, is your ECU working properly ?

It should take but a fraction of a second for the engine rpm to drop low enough for the next gear. About the time it takes to move the stick to the higher gear.

If anything, I might need to give gas if I waste to much time in neutral. If you have the time to wait in between upshifts, something is not right with your engine management.


Originally Posted by Korki Buchek
We are talking about different things by "double clutching."

I mean placing the transmission in neutral. Allowing the engine speed to drop. Then reengaging the transmission in a higher gear.

For example: If i want to shift from 2nd to 3d, I'll push the clutch in and disengage the transmission, then let the clutch out. Let the engine speed drop by a few RPMS, and then push the clutch in to reengage the transmission.

I don't mean increasing the speed of the synchro in the higher gear. You couldn't do that if you wanted to.
Old 06-16-2007, 07:08 PM
  #53  
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All this double-clutching must be the reason members are posting 15 second ETs. Too much playing with the damn clutch.
Old 06-16-2007, 07:13 PM
  #54  
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Originally Posted by Ziggyrama
That is correct. Sitting at a light with the clutch pressed in is called "riding the clutch".
I thought that riding the clutch was using the clutch to hold the car on a hill?
Old 06-16-2007, 07:15 PM
  #55  
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Originally Posted by davidv
I thought that riding the clutch was using the clutch to hold the car on a hill?
Don't confuse the kids any more!!!

Yeah, riding the clutch is what you said...
Old 06-16-2007, 08:41 PM
  #56  
silver350tn
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learn where your shift points are and dont use the clutch at all
Old 06-16-2007, 09:26 PM
  #57  
Korki Buchek
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I thought "riding the clutch" was driving around with your foot resting on the clutch peddle instead of the dead peddle?

learn where your shift points are and dont use the clutch at all
I have a friend with a transmission shop. Send me a PM when you need his number.
Old 06-17-2007, 03:59 AM
  #58  
bailey bill
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Originally Posted by Korki Buchek
I thought "riding the clutch" was driving around with your foot resting on the clutch peddle instead of the dead peddle?



r.

And we have a wnner!

bill
Old 06-17-2007, 07:25 AM
  #59  
keniff536
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Originally Posted by bailey bill
Amazing!!!

I've been drving manual trannies for over 50 years, and I never know it was so complicated.

And I never knew clutches and trannies were so fragile. I have abused both pretty badly at times, (showing off, racing, pulling trailers, etc) so I can't understand why I have never broken or worn out either one.

bill
+1

Just drive the car and enjoy it. If the OP is not grinding gears or anything like that, I doubt he is hurting the clutch or tranny. I've never replaced a clutch and I downshift every time I stop. Been driving manuals for over 30 years. If being smooth is what you want, concentrate on that and don't worry about the clutch.
Old 06-17-2007, 09:57 AM
  #60  
Fastass350z
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do think just do. focus on radio


Quick Reply: Quick question about "rev-matching" and wearing on the clutch.



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