Double clutching, or just rev match?
12-15-2004, 09:03 AM
#16
Originally Posted by yaya
if you understand the basics of a convential manual transmission you will understand double clutching has absolutely NO PURPOSE AT ALL. double clutching IS in-fact necessary on very stout trannys on tractors or heavy duty machinery without syncronizers that you would see in a construction yard. NOT YOUR 05 STI.
By the way, WHY DO YOU YELL TO MAKE YOUR POINT?
Originally Posted by Z1 Performance
I'd submit all of it is a collassal waste of time...neither gets you around a track or to the grocery store any quicker, and as Gary said, you stand a bigger chance of breaking something.
I don't think I ever said there is a bigger chance of breaking something using double-clutching. I looked but couldn't find any reference to that.
Gary
Sheehan Motor Racing
www.teamSMR.com
Last edited by GarySheehan; 12-15-2004 at 09:07 AM.
12-15-2004, 10:22 AM
#18
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Double clutching is mainly used in racing so that the weight balance of the car is not disrupted during a downshift. Slamming into a lower a gear puts more weight on the rear of the car and can cause a loss of control. Double clutching allows the flywheel and drivetrain to spin at the same rpm maintaining the balance of the car.
12-15-2004, 11:29 AM
#19
Originally Posted by mbquarts
Double clutching is mainly used in racing so that the weight balance of the car is not disrupted during a downshift.
Originally Posted by mbquarts
Slamming into a lower a gear puts more weight on the rear of the car and can cause a loss of control.
Originally Posted by mbquarts
Double clutching allows the flywheel and drivetrain to spin at the same rpm maintaining the balance of the car.
Gary
Sheehan Motor Racing
www.teamSMR.com
Last edited by GarySheehan; 12-15-2004 at 11:32 AM.
12-15-2004, 01:51 PM
#20
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Weight transfers to the front of the car when the clutch is depressed, and then transfers to the rear when the clutch is engaged. This will happen regardless of what technique you use. You can control the weight transfer with double clutching and heel toe. Double clutching helps to eliminate the rapid weight transfer to rear wheels, and heel toe can be used to transfer weight to the front wheels.
12-15-2004, 07:55 PM
#21
Originally Posted by mbquarts
Weight transfers to the front of the car when the clutch is depressed, and then transfers to the rear when the clutch is engaged. This will happen regardless of what technique you use. You can control the weight transfer with double clutching and heel toe. Double clutching helps to eliminate the rapid weight transfer to rear wheels, and heel toe can be used to transfer weight to the front wheels.
Are you talking about a braking situation? If so, while the clutch is engaged, the driven wheels are doing a very small fraction of the deceleration of the car due to engine compression, which transfers weight to the front of the car (i.e.-nose dives during deceleration). When you depress the clutch, that small portion of the decelerative force from engine compression is removed and a miniscule amount of weight is transferred rearward. If you are in a hard braking situation, this is negligible, since the brakes are doing 99.9% of deceleration and are the sole factor in weight transfer.
The only thing double clutching does is match the transmission input shaft rpm to layshaft rpm.
Where are you getting weight transfer from?
Gary
Sheehan Motor Racing
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12-15-2004, 09:42 PM
#22
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Weight transfer comes from slamming gears on a downshift. When you shift without matching revs the car lurches forward and weight is transfered to the rear wheels. You have to agree with this.
Like I said before revmatching or double clutching eliminates the lurch, hench it eliminates most of the weight transfer, thus it is controling weight transfer. I realize that this is not the only reason to revmatch or double clutch, but it is a factor.
I think we are on the same page, but for some reason we aren't seeing eye to eye on this.
Like I said before revmatching or double clutching eliminates the lurch, hench it eliminates most of the weight transfer, thus it is controling weight transfer. I realize that this is not the only reason to revmatch or double clutch, but it is a factor.
I think we are on the same page, but for some reason we aren't seeing eye to eye on this.
12-15-2004, 11:08 PM
#23
Originally Posted by mbquarts
Weight transfer comes from slamming gears on a downshift. When you shift without matching revs the car lurches forward and weight is transfered to the rear wheels. You have to agree with this.
When you slam gears in a downshift without rev matching, the car does not lurch forward, YOU do. The car's sudden deceleration that results from instantaneous engine compression forces a weight transfer to the FRONT. That is why YOU (your body) lurches forward. That's why the tissue box flys off the rear deck and hits you in the head. That's why the nose of your car dips closer to the ground. Weight transfer to the front makes the springs compress. Please, take a minute, breath, and think this through.
Originally Posted by mbquarts
Like I said before revmatching or double clutching eliminates the lurch, hench it eliminates most of the weight transfer, thus it is controling weight transfer. I realize that this is not the only reason to revmatch or double clutch, but it is a factor.
Originally Posted by mbquarts
I think we are on the same page, but for some reason we aren't seeing eye to eye on this.
Gary
Sheehan Motor Racing
www.teamSMR.com
12-16-2004, 09:26 AM
#25
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Originally Posted by GarySheehan
If you stop saying that there is a weight transfer to the rear during any type of deceleration, we will be getting closer to seeing eye to eye
btw no offense to you, but we aren't able to communicate on this for some reason.
12-16-2004, 09:58 AM
#26
Originally Posted by mbquarts
I never said that. It seems like I write something and you are responding about something else. I am going to have bail out of this thread...pulls ripcord.
Originally Posted by mbquarts
Weight transfer comes from slamming gears on a downshift. When you shift without matching revs the car lurches forward and weight is transfered to the rear wheels. You have to agree with this.
Gary
Sheehan Motor Racing
www.teamSMR.com
12-20-2004, 10:45 AM
#28
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I think the confussion in this thread comes from the fact that I was talking about accelerating and Gary was talking about decelerating.
I was talking about accelerating out of a turn, and I think Gary was talking about decelerating into a turn.
I was talking about accelerating out of a turn, and I think Gary was talking about decelerating into a turn.
12-20-2004, 04:04 PM
#29
Originally Posted by mbquarts
I think the confussion in this thread comes from the fact that I was talking about accelerating and Gary was talking about decelerating.
I was talking about accelerating out of a turn, and I think Gary was talking about decelerating into a turn.
I was talking about accelerating out of a turn, and I think Gary was talking about decelerating into a turn.
Gary
Sheehan Motor Racing
www.teamSMR.com
12-22-2004, 02:51 AM
#30
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I read though this entire thread and I now know way more then I ever wanted about heel-toe and double-clutching. I did a few more searches and found this. Might be a good laugh for those of you who are the real gurus of the technique...
Warning: Fast and the Furious references up ahead!
http://www.automotiveforums.com/t116979.html
Warning: Fast and the Furious references up ahead!
http://www.automotiveforums.com/t116979.html
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