ColorChange

Larry, this doesn't make sense to me. To "normally" double clutch downshift, you do the following:

Step A
1. relax the throttle
2. push in the clutch
3. shift to neutral

Step B
4. release the clutch
5. blip the throttle to rev match the lower gear

Step C
6. depress the clutch
7. grab the desired gear
8. release the clutch

This is how I was doing it and how most texts describe it. From looking at the video, I find it hard to believe that he can do all 3 steps that quickly. My understanding is the fastest guys do what I described:

Step A
1. relax the throttle
2. pull the gear into neutral (with the clutch out)

Step B
3. blip

Step C
4. depress the clutch
5. grab the desired gear

This way is one pushing of the clutch and sure looks like what he is doing.

Larry Herman

Tim, I realize that I did not make myself clear. This is what he is doing:

Step A
1. relax the throttle

Step B
2. depress the clutch
3. blip throttle to match revs

Step C
4. downshift one gear
5. release clutch

Repeat as required

This is one push of the clutch for each gear change. The idea is to get the powertrain re-engaged as fast as possible to assist with engine braking. I do what I do to assist with drivetrain longevity.

Greg Fishman

I do it exactly the way Larry describes above but I don't let out the clutch at each gear, just the one I want to be in as I head into the turn. What is the benefit of letting the clutch out at every gear?


Also the 996GT3RS probably doesn't need more than a few inches of clutch travel, compared to the 9 inches of travel in a stock car's clutch, to disengage the clutch.

PatK-Mpls

Larry-

To your point about potentially bending and/or breaking the shifter: have seen two seperate occasions where people driving GT3's have broken the shift lever off in their hand from trying to slam it in gear fast. (Also note that the Cup/R/RS/RSR shifter is a beefed up shaft as well!)

ColorChange

Larry and Greg: Your method is doing very little to help your transmission and is not double clutch downshifting. You can argue it's not necessary, but that is at a minimum, a personal choice that is undisputably easier on your transmission.

The key is when you blip (with the clutch in), you are not speed matching the input shaft with the pinion gear, and your synchros have to do the work.

If you blip with the clutch out, you match the shaft speeds thereby relieving your synchros of doing the work. It is more difficult to do but better for your transmission. Plus, you can hop in straight cut boxes, drive older cars where the synchros are not very good, etc.

Now I do agree with you, I currently just wait and grab the gear I want after a big decel. What I am told by the really good drivers is that it becomes a habit and a timing rhythm thing and it's just easier to run through all the gears.

Leh, please comment directly. Are you slipping the car out of gear and then blipping once with throttle when the clutch is out, or are you depressing and releasing the clutch twice?

Jarez Mifkin

Forgive if I'm wrong, but is Leh not just doing simple heel & toe downshifting?

Greg Fishman

I agree that the way I downshift is not the absolute best on the tranny as you are requiring the synchros to do some work. Having said that I have racing synchros that are much more durable than the brass ones in most street cars and this gear box has lasted over 5 years with no rebuild or any notchy shifting. When changing the fluid there is very little evidence of synchro shavings, as my mechanic calls it. I run through all the gears most times, but the clutch is only disengaged once even when going down several gears.

Larry Herman

Tim, what I described to you is not what I do. It is what Leh is doing. What you understand to be, and what you have accurately described as double-clutch downshifting is what I do. Twice on the clutch pedal for each gear change. This does save wear and tear on the transmission.

What I don't do is row through the gears. I go directly from the gear that I am in, to the gear I want to be in (i.e. 5th to 2nd). I do this just before I turn in. This gives me the most time to concentrate on maximum braking. This is also easier on the trans.

In re-reading my last post of "I do what I do to assist with drivetrain longevity" I realize that though I thought that I was referring to my double-clutch downshifting, in reality it was not clearly inferred. This English language is a bitch.

ColorChange

OK, Larry, you and I are doing the same thing (although I'm sure you are still faster at it than me). But, after looking at Leh's video, the second way I described is much quicker and I think I will try to learn it. Luckily, I can practice on my simulator.

Greg, 5 years is a long time with a lot of track time and as I recall, you were quick shifting but certainly weren't slamming them and pulling the gear shift out of the floor so your way is certainly reasonable. Like I said, it's a tough call. I may just give up and do it your way but I'm going to try to do it like Leh first.

kingleh

ok

im in 6th
take foot off gas
hit brake
mash in clutch
roll rite foot on the gas to BLIP while at the same time taking shifter out of 6th and putting it in 5th
then let foot off clutch

then do it again for the ramaining gears.

carreracup21

Hey Leh,
How was Homestead ? Looks like you guys ran well. Great job !!

kingleh

it was good

we gotta get the car going a little bit faster and we will be rite there.

Though we had 3rd but ended up 5th. Wich is ok i guess.

better luck next time.


Everything went GREAT on and off the track thanks to Autometrics. They really know what there doing.

TT Surgeon

Leh, that is one awsome job of driving.