So do you...(shifting question)

Doug Jackson · **Posted:** Thu Sep 23, 2004 12:22 pm

...double clutch, rev match or let the synchros do the work?

Scott Johnson · **Posted:** Thu Sep 23, 2004 12:28 pm

No option for "all of the above."

I'd say 80% of all autocross runs utilize ONE shift in my car, and it has no torque. That shift is 1-2, and typically I'll short shift it.

In the event there are some downshifts, I sometimes double clutch the 2-1 downshift, the rest of the time I just jam it in there.

In the event it's a 3rd gear course I will simply rev match the shift into 2nd and let the synchro's do the real work.

Obviously I don't do any of that crap on up shifts.

Scott

MikeWhitney · **Joined:** Wed Aug 20, 2003 9:15 pm **Posts:** 4724

I do what Scott says with the exception that I *always* double-clutch a downshift to first. It's habit now, and it makes a high-speed shift (ie pivot) to first very smooth. I heel-toe rev-match every downshift I make, street, autocross, rallycross, track. Again, habit

My clutch thanks me for that.

Kevin Allen · **Joined:** Thu Aug 28, 2003 6:42 pm **Posts:** 3479

What Mike said.

Except that I can only go to first while the wheels are turning with the silver car - so if I'm rallyxing the blue car, I have the ABS turned off. (clutch in, out of gear, clutch out, lock up wheels, clutch in, shift to first, match revs, let out clutch & haul ass out of there) :roll:

Aaron Buckley · **Posted:** Thu Sep 23, 2004 1:16 pm

I just shift, even when going to 1st. No double clutch, rev match depending on the course, but to rev match at 6-7k can be interesting:) Generally speaking, even with my low torque beast, I rarely have to shift beyond the initial 1-2. - AB

Kevin Allen · **Joined:** Thu Aug 28, 2003 6:42 pm **Posts:** 3479

I just wanted to add that unless you're really, REALLY good or your car has almost zero low-end torque (and this does NOT include any class variation of the WRX!), you shouldn't be downshifting to 1st on a "normal" autox course. I see lots of people downshifting choppily into 1st & wasting time/ blowing their line into a corner, then having to upshift again & wasting time again/ blowing their line out of a corner, when they could've just run a better line & been smooth on the brake & gas & ended up getting through that particular section a lot quicker.

Don't try to manhandle the car through turnarounds, just keep it simple & be smooth & you'll most likely be faster.

DickRasmussen · **Posted:** Thu Sep 23, 2004 4:16 pm

What is a syncro? :roll:

(no syncros in a Hewland gearbox)

DickRasmussen · **Posted:** Thu Sep 23, 2004 4:25 pm

More seriously: I use the clutch with all shifts, even with the racing car. Lots of reasons including $$$, smoothness, and "coordination" or lack thereof. I double clutch essentially ALL downshifts on the street but rarely in any kind of autocross situation, even before getting the race car. However, I rarely downshift in an autocross in a "street" based car or in the race car unless it is one of those high speed/low speed courses. As noted above, a lot of people downshift when they don't need to do so. My rule is that if I get wheelspin in the taller gear while exiting the corner on the limit, then why downshift to a gear that will cause more wheelspin and require a downshift and an upshift?

Doug Jackson · **Posted:** Fri Sep 24, 2004 7:34 am

Kevin Allen wrote:

What Mike said.

(clutch in, out of gear, clutch out, lock up wheels, clutch in, shift to first, match revs, let out clutch & haul ass out of there) :roll:

Wow, now that's involved! Too much going on for my mind to keep up with!

I've been reading up a little on double-clutching and for the last couple of days I've been practicing, mostly on upshifts for now because it's easier. I think it'd be a good habit to develop for the longevity of the Miata's tranny, being 14 years old and a little stiff into 2nd and 4th. It's certainly not bad, but double-clutching seems to really make the difference in a near-seemless engagement and a seemless one. It's still nothing like the Jetta's original tranny 2nd gear grind I lived with for 4 years. :shock:

DickRasmussen · **Posted:** Fri Sep 24, 2004 8:08 am

Doug,

I'm not sure "how" to double clutch an upshift. Simply shift a little slower to let the engine speed slow down to match revs with what is needed for the taller gear. Really only an issue with high rpm up shifts.

Carl Fisher · **Posted:** Fri Sep 24, 2004 9:17 am

I remember an interview with a manager of some GTP team (Ford, Rousch?) a year or 2 back talking about their success, and the topic turned to driving technique. The quote I remember: "We don't do any of that fruit-cup heel-and-toe crap."

Of course I'm sure they take the tranny apart after every race anyway, but still, you gotta love it... :-)

Doug Jackson · **Posted:** Fri Sep 24, 2004 7:14 pm

Dick, I'm doing it for practice. The more comfortable I get double-clutching on the street, the easier it will be on course. If I double-clutch up-shift as well as down, I get twice the practice. I'm just trying to get my leg used to pressing, quickly letting the clutch out and back in for the next gear. Also getting my hand used to pausing between gears. I'll leave all that crap behind this weekend tho. I've only been playing around with it a few days so I'm not going to blow a run by screwing up a shift because I was trying to double-clutch too fast.

Andy Greene · **Posted:** Mon Sep 27, 2004 3:22 pm

I usually heel-toe rev-match almost all down shifts on the street, but I never double-clutch. I've never gotten enough practice to do it quickly.

Todd Breakey · **Posted:** Mon Sep 27, 2004 3:28 pm

What is the advantage to double clutching as opposed to just rev matching you down shifts?

Chuck Frank · **Posted:** Mon Sep 27, 2004 3:49 pm

rev match with throttle and clutch slippage when downshifting to 1st for a turn around cone if needed to keep the car from standing on it's nose, but otherwise I use what I paid for and let the syncros do what they're designed to do. I try to get the shift (s) over with as quickly as possible, even a fast 1-2 shift costs ~ 0.1 sec.
IMHO Heel-toe and double clutch went out with non syncro trannies and handbrake turns, fun to do to impress your friends, but if little use on an AX course. With careful rev matching, it's possible to shift without using the clutch at all. now THAT will impress your friends!

THSCC Forums

So do you...(shifting question)

Who is online