Double Clutch Heel Toe Downshift

[wgnths]

This is how it's done.:cool:
http://www.youtube.com/watch?v=0j-3xIZK-Bk&mode=related&search=

[moxie]

I'm faster...

;)

[pickinicholas]

I wish I had the room to heel toe...

[Cobalt_Supercharged]

I wish the Cobalt's pedals were placed better to heel toe. Luckily I can just barely hit the gas with the side of my foot when on the brake. Knowing my luck my foot will slip one of these days and I'll go through a wall or another car.

[Max Power]

If you've got synchros, double clutching when you're heel and toeing is just a waste of time. I learned it from my dad and the instructors at Bondurant called me "old timer" when I did it. I now abuse my synchros ;)

[wgnths]

you know some of those Bondurant guys still double clutch. once you learn it, I think it's hard to break. I never really did it, and I'm too lazy to really try.

[moxie]

If you've got synchros, double clutching when you're heel and toeing is just a waste of time. I learned it from my dad and the instructors at Bondurant called me "old timer" when I did it. I now abuse my synchros ;)

Yeah, this is true.

It would take more effort to "unlearn" it though...
I have tried to not do it, and ended up spinning into the gravel at PIR...

I never learned to do it to be easier on the synchros, its just how I learned to do it. And it makes me better than you.

[Max Power]

Wrong... because by definition, you can never be faster than me.

[moxie]

I guess you may be right...

Technically since you are too wimpy to go to the track, I'll never know how slow you really are. So we can't be sure how much faster I really am.

[moxie]

Really good post on NASIOC about the perceived time loss due to Double Clutching the DownShift..

link: http://forums.nasioc.com/forums/showpost.php?p=15996291&postcount=60


I've posted this info elsewhere in the forum, but it looks like it might be helpful here.

When you guys are discussing double-clutching, you are walking through the steps serially, like this...

1. brake
2. clutch in
3. shift to neutral
4. clutch out
5. blip throttle
6. clutch back in
7. select next lower gear
8. clutch back out
9. off brakes

This serial processing is accurate when you are thinking about an action consciously. But when you process unconciously, your body can parallel process and do quite complicated things. Take walking for instance. Try and figure out all the steps required to walk down a hallway. There are so many it would be overwhelming and we'd decide to just stay on the couch.

So, when you consider how double-clutching works when your body processes in parallel, it isn't any slower. The reason is, you are not actually going through the 9 steps listed above. Things are going in that order, but actions are happening in parallel.

There are three ballistic actions that occur during a double-clutch. A ballistic action is an action that your brain starts, but doesn't have to finish because your body is programmed to complete the series of actions. Here are the three actions my body performs when I double-clutch. These are not in order, they are parallel processes that are synchronized appropriately.

1. Right foot depresses brake, throws in a throttle blip at some point and comes off the brakes later.
2. Right hand moves shift lever to neutral, then to next lower gear.
3. Left foot pumps clutch twice quickly

So, when you think about the body's ability to parallel process, it becomes a much simpler task of perfoming three synchronized actions simultaneously rather than performing nine seperate actions serially.

To show how a double-clutch is no slower than a single-clutch, let's look at what happens during a single-clutch:

1. Right foot depresses brake, throws in a throttle blip at some point and comes off the brake later.
2. Right hand moves shift lever to neutral, then to next lower gear.
3. Left foot pushes clutch down for the duration of (2) above.

So the only difference between the two is the left foot pumps the clutch twice quickly instead of holding the clutch down for a longer single cycle. The KEY here is that there is no pause while the shift lever is in neutral. As the shift lever is passing through neutral, the clutch is already out and the throttle has been blipped. No extra time was used.

Consider these three parallel processes (rather than nine individual steps) and watch the video again. It's clear that there are three processes taking place that are just tightly synchronized.

http://www.teamsmr.com/movies/Footbox%20Small.wmv

Does that help explain it?

[speedblind]

Interesting to watch. I was taught to hold the clutch down the whole time. Thinking through things, I can't really see the difference between double clutching and single. Can anybody explain it to me? I've never driven a dog box, but I can't imagine why pushing the clutch in twice quickly would have a different effect than holding the clutch down. With the clutch disengaged, the shifter should go into gear, and then the blip matches the engine's revs and all is well.

What am I missing?

[moxie]

Well, the basic principle behind the double clutch is that you actually engage the clutch while you blip the throttle.

This actually engages the transmission, so that both the engine and the transmission internals are at the proper speed when the downshift is completed.

With a single clutch heel toe, you speed up the engine and rely on the sychros to match up the transmissions internal speeds. Which is why they are there in the first place incidentally.


I do it because I like the "idea" that I am putting less load on the synchros, and also because I am so trained at this point it would be harder to learn to single clutch.