Double Clutching

[NutBucket]

Originally posted by: TheLonelyPhoenix

Originally posted by: NutBucket

Originally posted by: chowmein
they should burn every copy of F&F

Come on now, be a good sport. Its entertaining enough to be worthwhile. Not so sure about the 2nd one though.

It's entertaining in the same way seeing Skywalker or WayneTek post a YAGT was entertaining.

Painful and fun to laugh at?

 

[chowmein]

if i remember correctly in F&F, there was a scene where some retard w/ VW Jetta raced a S2000 ... thinking he can win.

scene also included BOTH cars using NOS ...

 

[TheLonelyPhoenix]

Originally posted by: NutBucket

Originally posted by: TheLonelyPhoenix

Originally posted by: NutBucket

Originally posted by: chowmein
they should burn every copy of F&F

Come on now, be a good sport. Its entertaining enough to be worthwhile. Not so sure about the 2nd one though.

It's entertaining in the same way seeing Skywalker or WayneTek post a YAGT was entertaining.

Painful and fun to laugh at?

:thumbsup:

 

[Vic]

Originally posted by: raptor13
Assuming your example track car still has a synchomesh tranny, why is double clutching on the downshift necessary? You might be able to do it just to do it in the time it takes to rev match but if you're already heel-toeing... what's the point?

Double-clutching in a synchromesh transmission is almost never necessary, and does nothing without proper rev-matching. Both double-clutch and rev-matching are unnecessary for normal street driving, but can increase clutch and transmission life, and (when performed properly) provide for smoother shifting for yourself and your passengers' comforts.

How double-clutching helps is this: when shifting, there are separate 3 spinning components to be controlled, not just 2 like most people think. There is the engine, the transmission input shaft, and the tranmission output shaft. Rev-matching only matches the engine speed to the output shaft speed (as reduced or multiplied by the transmission gearing). When the clutch is in and the transmission is in neutral, the input shaft is free-spinning. Proper double-clutching allows you to increase the speed of the input shaft as well as the engine speed with the throttle blip of the engine rev-match.
In sequence: clutch in, shift out to neutral, clutch out, blip throttle rev-match (both engine speed and input shaft will be increased with clutch out), clutch in, downshift into appropriate gear, clutch out.

Personally, I only double-clutch for downshifts into 2nd and 1st (and I very rarely downshift into 1st while moving, only when absolutely necessary), as the differences in ratios and inertial masses are highest for those gears.

 

[jlee]

I double clutch most downshifts (except from 5th to 4th..don't typically bother)..but never for an upshift..

 

[Jzero]

I double-clutch downshifts on the road, although only because it provides a smoother experience.

 

[AMCRambler]

It still doesn't make sense to me if double clutching is what I think it is. Double clutch is when you push the clutch, take the transmission out of gear, let go of the clutch, then push the clutch again, and put it back in gear right? In which case if you're not putting the car in gear after coming off the clutch you do nothing but stretch the amount of time between your shifts. I've got a friend who's dad is a driving instructor and taught me how to drive. He also used to drive tractor trailers before he became an instructor. He told me the only thing you double clutch is one of those big rigs. They teach you to do that so that you don't shift gears too fast. Lets the rpms drop which on the large trucks with the big transmissions takes longer. So they would teach noobs to double clutch so that they wouldn't throw it into gear again too quickly. Once you knew what you were doing, you knew how long to wait before shiftng into gear and there was no need to double clutch. On a car, I can't see any reason for it. The rpm's fall off quick enough that by the time you double clutch, you've missed the optimal point to shift. This is what I got from him, I figured he should know, right?

 

[laurenlex]

I hate real player. Saved for home.

 

[hpkeeper]

Originally posted by: Spikesoldier
dont even use the clutch, just slam the thing into gears.

That's possible to do w/o grinding gears... I've done it several times on my jeep... the only gear you really need the clutch for is first gear.

 

[Wag]

Wasn't there a Seinfeld episode where George double-clutches?

 

[otispunkmeyer]

or u could have AUDI's wicked gearbox which spins up the next and previous gear read for use when u need it, apparently its about 4 times faster than a human gear change

 

[AgaBoogaBoo]

Originally posted by: Vic

Originally posted by: raptor13
Assuming your example track car still has a synchomesh tranny, why is double clutching on the downshift necessary? You might be able to do it just to do it in the time it takes to rev match but if you're already heel-toeing... what's the point?

Double-clutching in a synchromesh transmission is almost never necessary, and does nothing without proper rev-matching. Both double-clutch and rev-matching are unnecessary for normal street driving, but can increase clutch and transmission life, and (when performed properly) provide for smoother shifting for yourself and your passengers' comforts.

How double-clutching helps is this: when shifting, there are separate 3 spinning components to be controlled, not just 2 like most people think. There is the engine, the transmission input shaft, and the tranmission output shaft. Rev-matching only matches the engine speed to the output shaft speed (as reduced or multiplied by the transmission gearing). When the clutch is in and the transmission is in neutral, the input shaft is free-spinning. Proper double-clutching allows you to increase the speed of the input shaft as well as the engine speed with the throttle blip of the engine rev-match.
In sequence: clutch in, shift out to neutral, clutch out, blip throttle rev-match (both engine speed and input shaft will be increased with clutch out), clutch in, downshift into appropriate gear, clutch out.

Personally, I only double-clutch for downshifts into 2nd and 1st (and I very rarely downshift into 1st while moving, only when absolutely necessary), as the differences in ratios and inertial masses are highest for those gears.

You know your facts

 

[TheLonelyPhoenix]

Originally posted by: otispunkmeyer
or u could have AUDI's wicked gearbox which spins up the next and previous gear read for use when u need it, apparently its about 4 times faster than a human gear change

Yeah, dual-clutch system... those are awesome. Allows a shift with virtually zero time in neutral.

 

[MikeMike]

Originally posted by: chowmein

generally isn't double-clutching used for redline control downshifting?

i was about to say "Why are you downshifting in a 1/4 mile?"

but its already been covered.

MIKE