OK - Is it true there's no synchro on the GS-R first gear? If so, it seems double-clutching would be necessary. So why would people tell me NOT to double clutch on the 2-1?
I'm trying to learn how to properly heel-toe/double clutch downshift, and this has been a confusing point for me so far.
Any other suggestions related to this question are welcome!

 

No, there is a sychro on the GS-R 1-2. The ratio is so far off though that with any amount speed it's hard to shift into first, and pretty hard on the synchro. Yes double-clutching will help but it's still bad..... when do you ever need to be dounble clutching that shift anyway? Surely not on the street or track.


[Modified by sackdz, 11:22 AM 12/5/2001]

 

If you want to learn to heel-toe, try heel-toeing on the 3-2 downshift. That will be much more friendly to your tranny.

 

Autocross sometimes. If the corner is very tight you'll bog big time in second. Mostly you shouldn't worry about it, though.. unless you're very good, the cost in time and smoothness in the 2-1 shift and then the following 1-2 shift is greater than the benefit you get from the better acceleration.

 

They are not two words to describe the same thing.

Heel-toe is essentially blipping the throttle while braking (usually to match revs so the engine does not cause the car to lurch when you let the clutch out). It describes the act of using one foot to operate both pedals.

Double clutching is essentially blipping the throttle while the gear selector is in neutral to rev match the lay shaft to the speed of the transmission's output shaft in the gear you are about to select. This can be combined with heel-toe, but doesn't technically have to be. Double clutch gets its name from you pushing in and releasing the clutch twice for each downshift.

At performance events, you'll see heel-toeing without double clutching (let the synchros handle the layshaft's speed), but I'd be surprised if you ever see double clutching without heel-toe (take your foot off the brake while downshifting?!?).

In summary, there are three terms involved here that are similar, yet different..

double clutch - blipping the throttle in neutral before selecting the next gear (clutch is out)

heel-toe - blipping the throttle while braking (clutch is usually in)

rev-matching - blipping the throttle for the purpose of matching the speeds of two rotating pieces of equipment. Sometimes you rev-match the lay shaft to the gear you want (the goal for double clutch), sometimes you rev-match the engine to the speed of your transmission for the gear it is in (the most common goal for heel-toe).

blah.. don't know how comprehensible that is..

Edit: ack! contradicted myself.. I think that fixed it..
Edit: not completely.. I think _now_ it's good...


[Modified by MechE00, 9:38 AM 12/5/2001]


[Modified by MechE00, 9:39 AM 12/5/2001]

 

What about the rare occurrance of going up a hill while you're stuck in 4th? Well, um, the driver would have to be pretty stupid to have that happen with an Integra unless the hill is right at the end of a straight, but still...

I double-clutch when I heel-toe but have been told it's useless. Whatever.

 

I guess that was my actual question, when you boil it down. Is there ever really a time you need to 2-1 in an autocross?There was one turn this past weekend where it seemed 2 was bogging down. I kept it in 2 cause I wasn't confident enough in my abilities to try the downshift, especially with another hard turn immediately after that one.

 

Well, as you said, at a performance event this would not likely happen. Integra shift points are pretty much at redline, so if you've upshifted to fourth, that would have to be one heck of a hill to bog you.. but I dunno.. I actually don't do open tracking or hill climbs (must resist black hole of money spent on performance driving)-- I only do autox..

Besides, just about every downshift except the 2-1 is usually (by my second/third hand understanding) done just allowing the synchros to handle the layshaft.. I know some people claim they can double clutch as fast as they can shift without double clutching, but I can't believe it. So if you're downshifting under power, I wouldn't bother with double clutching.

double clutching & heel-toeing to 1st is not necessarily useless-- it's a bear to get the selector into first at speed without double clutching. It's just that 1st is such a short gear that it's _real_ tough to get the second rev-match done smoothly.. and then when I'm coming out of a corner, I'm at least 50% likely to lite up the inside tire due to not being gentle enough on the throttle.. (dang open differential.. and dang my poor driving skills! or is that sKiLlZ?)