turborambler

Hello folks,

I have a 2004 WRX with a few mods and have about 6800 miles on the car. I have a question about rev matching and double clutching. When I first started to try and refine my driving technique, I wanted to smooth out the down shifts, so I read up about rev matching. I quickly realized that the best way under hard driving would be to heel toe it, but its hard to practice and since I'm about 5'8 I think I would have to put the seat real close to do it...not too good for daily driving. So I adopted the following technique for down shifting into turns....say a highway off ramp. It goes

1) Brake
2)Clutch in.
3)Down shift (select gear)
4)Hit the throttle to rev match.
5)Let the clutch out...quickly.

I can do this fairly quickly with what seems like a flurry of feet movememt....lol. I can do it so the car doesn't jerk, or anything. Although when I was learning this I let the clutch out fast once when the rpms were too low and it was not pleasant...plus it was on the way to work...So I was happy with this until I read about double clutching. So I've been practicing that with the sequence:

1)Brake
2)Clutch in.
3)Neutral
4)clutch out
5)blip gas
6)clutch in
7) Select gear (down shift)
8)rev match
9) clutch out.

When I do this quickly it results in a vroom VROOOM from my Greddy Exhaust and about the same feeling as when I use the first technique...no jerking....you really can't even feel the shift anywhere in the car, almost like you put it in neutral. I still screw this up sometimes, but it is almost routine now. I know double clutching is good for the synchros and I can feel that, but is this whole procedure worth it? I mean I can just rev match with clutch in initially a lot faster. The friends I have who drive stick aren't exactly performance minded...so they have no idea about any of it. So my question is...is the first method OK? Is one better than the other? Is it bad to rev it with clutch in? Sometimes I really have to "goose" it to do this whole thing smoothly. Thanks for your input and I look forward to discussing this with the group.

jdepould

iTrader: (2)

just rev match, double clutching is pointless unless you're on the track

MVWRX

iTrader: (1)

I was wondering the same thing. I did the reverse though; when I got my rex I learned how to double clutch, heal toe, and blip rev match all at the same time. Then I got lazy and started just heal toe and rev matching. Like you said, I can tell the difference getting the car in gear (much smoother with double clutch). But I also don't like kicking my clutch that much and I'm sorta lazy. So now I double clutch only if there's a huge difference in my down shift (like if I have to slow down a lot quickly, from 4th to 2nd, I'll double it). Also, I double clutch getting into first because other wise I usually grind.

MVWRX

iTrader: (1)

That doesn't make sense to me. Double clutching is slower (it has to be, it takes more time to hit the clutch twice than it does to hit it once), and the reason racers do it is because a lot of them don't have syncros so they have to double clutch in order to get the car in gear.

jdepould

iTrader: (2)

when you're in the middle of a turn it can help you. There's a technical thread somewhere on here about it. The only time double clutching makes sense on the street is when reverse is being a *****

MVWRX

iTrader: (1)

When you're in the middle of a turn, rev matching and toe heeling can help. Noone's ever given me a good explanation for why they think double clutching is faster in a car with syncros(in a turn or not, either way it's slower...). The double clutching is to get the flywheel and tranny spinning the same speed so it slips into gear (neccesary if you have a dog box). But if you can get it into gear without double clutching, it MUST be faster without the double clutch. Double clutching can only possibly limit some wear on the syncros (and like you said, make it so it's possible to get into that damned reverse gear).

bassplayrr

iTrader: (9)

Double clutching is more of a syncro issue than a speed issue. Double clutching is required on race trannys that have no syncros in order to allow the tranny input shaft to catch up to the engine rpm (which revving with just the clutch in won't do.) Even if you have syncros, double clutching will save wear on those syncros, which is a big concern with our sh1tty grind prone Subaru units. Double clutching done right can be just as fast as no double clutching. As proof, watch the footbox video on Gary Sheehan's website. You try and tell me that you can do a standard rev match any faster than that.

-Chris

http://www.teamsmr.com/html/videos.html it's the second vid down.

MVWRX

iTrader: (1)

I agree completely...I wasn't trying to say I can rev match w/o double clutching faster than everyone who double clutches...I was just saying that, for example, Gary Sheehan can probably single clutch rev match faster than he can double clutch. Not much of a difference in time probably, but physics and common sense say that pushing the clutch twice HAS to take a longer time than hitting it once.

MyRuRex

That was nice.....I just do the simple heel toe stuff on the street. No where near skilled enuff to do that. SWEET

bassplayrr

iTrader: (9)

Yeah, sorry... I was replying to an earlier post, not yours. I agree that single clutching is always faster than double clutching done by the same person, but the amount of wear you save on the ghetto syncros IMO is worth it. I do it whenever possible. Nuts to the OEM subaru syncros.

-Chris

GarySheehan

iTrader: (1)

Yes, a double-clutch does take longer than a single clutch, but what's the rush? I'm just going to be sitting there waiting for the car to slow down anyway, so why not save some wear on the car?

Gary
Sheehan Motor Racing
www.teamSMR.com

MVWRX

iTrader: (1)

Good point (of course). Thanks for the response! I never expected to get a reply from someone that knows as much first-hand about this as you!

MonkeyAB

iTrader: (1)

my t2 cents on this: Double clutching is more necessary in lower gears because the difference in gear ratio is greater. As the gear ratios get closer, (i.e. 5th to 4th or 4th to 3rd shifts) double clutching may not be as necessary because the difference in rotational speed of the gears is less. The decision is really up to the driver's personal preference. I try to always double clutch when going from 1st to reverse or vice versa. I also double clutch to downshift to 2nd. Rev matching onlyl affects engine speed, but double clutching helps to match the speeds of both shafts in the transmission.

Z1 Performance

iTrader: (7)

I'd submit all of it is a collassal waste of time...neither gets you around a track or to the grocery store any quicker, and as Gary said, you stand a bigger chance of breaking something

Adam