WTF is "double clutching"?

[MX2]

I thought drag racers used speed shifters

 

[James3shin]

if you want to win races, you gotta use the "naws," "speeed holes" and double clutch

 

[Adam8281]

It's what you do to a hot stranger just before you get arrested

 

[BriGy86]

im still trying to figure out what the front passanger floor board has to do with danger to the manafold

 

[quakefiend420]

Originally posted by: BriGy86
im still trying to figure out what the front passanger floor board has to do with danger to the manafold

that's where the doofanator valve is located, don't you know anything?

 

[Reckoner]

If you want fun then just use heel and toe

 

[arcenite]

word

 

[fitzov]

Originally posted by: Demon-Xanth
It's only for transmissions that aren't synchronized, which are VERY rare now. I haven't heard of them being in a performance app for a long time. Double clutching just wastes time. You'll see it most used in old trucks (LARGE trucks).

Yup. Most truckers don't even use the clutch they know the gears so well. When I first started driving I watched a 19 year old kid do it and was amazed.

 

[MysticLlama]

I have to do it every time to downshift into first at anything more than about 2mph, much of the time down into second, and sometimed down to third just to get the shifter to go into the gear.

Old synchros kinda suck sometimes. But it sounds neat.

 

[mugs]

It's funny, re: the pinks thread yesterday - the guys on the camaro board that the TransAm driver posts on said the ricers were probably telling the kid he should have double-clutched, and on the ricer board that the Civic driver was posting on someone yelled at him for granny shifting.

 

[paulney]

Originally posted by: fitzov

Originally posted by: Demon-Xanth
It's only for transmissions that aren't synchronized, which are VERY rare now. I haven't heard of them being in a performance app for a long time. Double clutching just wastes time. You'll see it most used in old trucks (LARGE trucks).

Yup. Most truckers don't even use the clutch they know the gears so well. When I first started driving I watched a 19 year old kid do it and was amazed.

How do they do it?

And besides, aren't trucks equipped with a pneumatic sequential gear box?

 

[fitzov]

They simply know from experience the right RPM for each gear. I've actually done it on my Civic a couple of times too. Rev the engine up to a certain RPM, take foot off gas, shift. It's a little more difficult when downshifting, but that can be done as well.

 

[Zenmervolt]

Originally posted by: Demon-Xanth
It's only for transmissions that aren't synchronized, which are VERY rare now. I haven't heard of them being in a performance app for a long time. Double clutching just wastes time. You'll see it most used in old trucks (LARGE trucks).

It's very useful on downshifts around a tight road course to make smooth downshifts. When going from 4th or 5th into 2nd, double clutching can speed up the downshift a lot over just trying to muscle the lever into position while waiting for the synchros to get everything meshed properly.

ZV

 

[Zenmervolt]

Originally posted by: TheLonelyPhoenix

Originally posted by: Biggerhammer
When shifting gears, you push in the clutch, shift to neutral, relase then push in the clutch again, then shift into the next gear.

It's necessary in transmissions that have no synchromesh, I think...

QFT.

I'm pretty sure truck drivers only double clutch just to keep themselves from shifting too fast.

Edit: Or in an older truck without a syncro-ed transmission, as someone else mentioned.

Actually, most semi drivers never use the clutch at all except for getting into 1st or reverse. After that they power-shift every time. Done right, it is very smooth. Truckers can get 500,000+ miles from a clutch by shifting without the clutch.

ZV

 

[jagec]

Originally posted by: paulney
How do they do it?

And besides, aren't trucks equipped with a pneumatic sequential gear box?

Trucks have a number of different transmissions, but a number of them have manual transmissions with no sychromesh, which means you gotta double-clutch.

Originally posted by: fitzov
They simply know from experience the right RPM for each gear. I've actually done it on my Civic a couple of times too. Rev the engine up to a certain RPM, take foot off gas, shift. It's a little more difficult when downshifting, but that can be done as well.

That's just revmatching, you have to release the clutch in neutral, rev the engine to slightly above the appropriate RPM for the next gear, and then push the clutch back in and shift to your gear for it to be "double-clutching"

And it's the LAST thing you want to do while drag racing, since it's MUCH slower.

 

[Chunkee]

Its the same as Double Dutch minus the C.

Enjoy.

JC

 

[Zenmervolt]

Originally posted by: Majunior

Originally posted by: spidey07
who the heck double clutches on an upshift???

The fast and furious writers didn't have a clue about what they were writing. You DON"T double clutch when up-shifting. there is no need to, the synchros are already running at the same speed as the engine.

You've never driven an old synchromesh transmission, have you. The 30 year old gearbox in my 914 is "full synchromesh" but it will still grind going from 1st to 2nd unless you double clutch. My 20 year old 951 will lock out of 2nd gear on cold mornings if I don't double-clutch the upshift too.

ZV

 

[spidey07]

Originally posted by: Zenmervolt
You've never driven an old synchromesh transmission, have you. The 30 year old gearbox in my 914 is "full synchromesh" but it will still grind going from 1st to 2nd unless you double clutch. My 20 year old 951 will lock out of 2nd gear on cold mornings if I don't double-clutch the upshift too.

ZV

bah, you just don't know how to shift.


ps - love the 914. little go carts. Is that a known issue with their trannys? I guess I can see the need to double clutch on something like that if it gives you fits.

 

[Gillbot]

Originally posted by: Tu13erhead
Google..

http://www.wisegeek.com/what-is-double-clutching.htm
http://www.answerbag.com/q_view.php/4101
http://www.epinions.com/auto-review-6902-1618F526-3A351631-prod4
http://en.wikipedia.org/wiki/Double_clutch
http://www.elecdesign.com/Articles/Index.cfm?AD=1&ArticleID=6137

:roll:

 

[chambersc]

Originally posted by: JoLLyRoGer
Anyone? Someone, please explain it to me???

you saw that episode of pinks, too?

 

[imported_LoKe]

Would double-clutching in an up-shift be a bad idea, or does it not matter?

 

[chambersc]

Originally posted by: LoKe
Would double-clutching in an up-shift be a bad idea, or does it not matter?

rofl, do you like to keep your engine in your car? if you do, i'd advise you not to go from 3rd to 1st.

 

[Hyudra]

Originally posted by: LoKe
Would double-clutching in an up-shift be a bad idea, or does it not matter?

The whole point of double clutching is like:

the engine is running at 3,000 rpm in 3rd gear at 40mph
you want to be in 2nd gear at the same speed, but obviously you need to be at a higher rev for that gear for the same speed
so you double clutch and blip the engine to say 4,000 rpms and downshift, and it'll be like you were always in 2nd gear. - if you didn't double clutch, the syncros bring up the revs to 4,000 rpms for you.

upshifting is the opposite
when you go from 2nd gear 4000rpms at 40mph to third, you go down 1000rpm. So there is no need to double clutch and blip the throttle in this case.