wilsonchristian

Hey all,

I've been double clutching for a couple weeks right now, and I was wondering how many of you guys have tried it.

I decided to go this way after reading and article on answers.com and a couple other automotive articles.

Double-clutching, is in essense just rev-matching. For example, when you accelerate the engine speed for a gear shift to say 3000 rpm, the next highest gear will engage optimally at 2000 rpm. Modern cars have synchros which take up the difference (and energy) between the optimal engage rpm and the actual engine rpm. Older trannys didn't have synchros so you had to just snap it in exactly the right rpm, otherwise, its a no-go.

Here's an example (dunno about the rpms as i go by sound ) :

1. Rev the engine rolling along in 2nd up to the shift rpm (~2500).

2. Pump the clutch 1x and shift to neutral (now pedal is up)

3. Pump the clutch down + shift to 3rd and snap the clutch out quickly.

4. If you got it right their is no rpm take-up or thump. You don't even feel it and your sunchros never got used.

Downshifting is another matter, the "brake and blip" method they talk about.

Some of you older guys might know this, but maybe some of the first time 5-speed owners might wanna know.

Hopefully this generates some interest and questions. Feel free to correct me.
Have a good one.

-Christian

Dan

I've done it but feel it is not needed whatsoever. The only arguement one would have is to save the synchros but they are more than capable of surviving the life of the car unless you grind the heck outta them.

If anything, you are wearing down your clutch by using it twice as often.

However, double-clutching is an excellent way to reinforce your understanding how the engine, gearbox/tranny work together. Fun to try, but no real need on a regular basis.

wilsonchristian

Once you start doing it, its darned addictive

I have heard you save the clutch by not having it depressed for as long. For example sitting at lights is rough on the 'ole clutch even fully depressed. Neutral, w/clutch out is better.

Maybe somebody else can clarify.

Oh, and Go Leafs Go.

-C

Enfynet

:scratch: I like the 'push clutch in, shift, release clutch' ... it saves me time trying to think about how little to touch the pedal with my size 13 Lugz...

Chef

work on heel-toeing, much more important.

double clutching is not neccessary.

ManEHawke

Unless I raced road courses, but I only commute
Those bearings will go bad since your linked to the flywheel, and imagine that poor crank over a long period of time.
Keeping clutch released as much as possible for the life of the car is good.
Because then when you are in neutral you hear clunking, and it'll magically go away when you press the clutch :shock:
(mustangs have this minimumly by nature so don't worry)
So I only do it to show off when someone is fortunate enough to get a ride from me.
A sychro will last a long time if you shift properly anyway.

1 COBRA

Please elaborate on the benefits and deficiencies of both practices. Thanks.

Rampant

Let me get this straight....
You are double-clutching just so you don't hold the clutch it while you let the engine drop RPM to minimize the impact on the synchros?

Isn't that why God created synchros in the first place?

Heck, just let up on the go-pedal to take the stress off the engine and you should be able to pop it in neutral without the clutch in the first place, and then you would even be "cooler" than double clutching.

Take it one step further and time it EXACTLY right and you should be able to quickly up-shift without the clutch at all (yes, I have seen it done, no I have not done it myself).

Or, you buy a lighter weight flywheel. That will drop the RPMS quicker during shifts (not to mention rev faster), so there will be less stress on the synchros (if that is a concern for you).

Perosnally, I am glad the new car doesn't ride/drive/shift like a 30+ year old car -- no matter how cool they were back in the day.

Rev-matching/heel-toe on a down-shift is different, becasue that is needed to combat a long clutch drag. There is no technology for that (on these cars at least).

Chef

Heel-toeing is a method for braking, revmatching and downshifting.

Benefit, it gives you even more control of your car. It allows you to rev match your next lower gear selection while applying brakes and selecting the next lower gear or gears, setting you up for WOT and acceleration as soon as possible again.

This link will explain it and show it properly done: http://www.turnfast.com/tech_driving..._heeltoe.shtml

phenomenal reference that explains alot: http://www.turnfast.com/

It is road course practice but is used daily as well. I use it every time I drive any standard vehicle, it's second nature now.

Negative, non really unless you can't do it correctly in which case you may crunch the next lower gear or over rev, but a quick clutch in can save you. But with practice is not that hard and practiced enough is not even a thought.

Double clutching is discussed above but is not neccessary for a transmission with synchros. Knowing how to do it is a good idea (God forbid you lose a synchro) but actually using it every day is a bit of a waste.

Heel-toeing is much more useful every day.

ManEHawke

I understand heel-toe & dble clutching very well.
In what type of scenario on the road would you use heel-toe?
Unless you're in the fwy and drift into a fwy overpass bridge with a curve lol.

I guess for normal daily driving I can't imagine how a simple rev matched downshift can be replaced.
For me it's fun to do it for fun, with no real reason, but you said it's useful for everyday.
Just curious?

Rampant

Rev-matching on a down-shift (heel-toe) saves the clutch under all circumstances. If you down-shift without re-matching, you have to drag out the clutch in a long, slow process to get the engine and driveline speeds to match. That is needless wear on the clutch.

Obviously, this is not coming to a stop at a light, but when you down-shift to go around turns, or if the light turns green when you are slowing, but haven't reached the line yet, etc.

ManEHawke

I have a different style.
Do you downshift through every gear when slowing down?
I just pop her in netral, and if light turns green, and I'm still rolling I can put her in the proper gear, and rev match properly.

it's just different styles, neither is wrong I suppose.

Chef

Decelerating into corners or sweepers, declining radius turns...

Quote:

Originally posted by ManEHawke@August 30, 2005, 1:40 AM
Unless you're in the fwy and drift into a fwy overpass bridge with a curve lol.

Why would you do that? I'm not talking street jackassery, it's putting track education to every day use that's all.

Quote:

Originally posted by ManEHawke@August 30, 2005, 1:40 AM
I guess for normal daily driving I can't imagine how a simple rev matched downshift can be replaced.

Because you're not thinking of combining braking and downshifting and maintaining or maximizing corner entry, carrythrough and exit speeds. Combine your simple revmatching and downshifting with braking and read the above link I provided. It's really not that hard and is even more fun.


<!--QuoteBegin-ManEHawke@August 30, 2005, 1:40 AM
For me it's fun to do it for fun, with no real reason, but you said it's useful for everyday.
Just curious?

Quoted post

[/quote]

No problem, it's a method of smoothing your inputs/controls and keeping the car and your driving as smooth as possible while maintaining speed.

To me, I can't think of driving standard any other way. There's no flat spots, or searching and or even really looking for or concentrating on the rev match. I'm always more concerned with getting back on the throttle.

ManEHawke

That's cool, I see what you're saying. I guess for me I have yet to come to a situation where I must do it. I could if I wanted to, but it's not necessary for the way I drive.
If I need to brake on a curve normally I have no need to shave a second on how fast I get around it. I'll just calmy apply brakes, clutch, put in neutral, coast, slow down, pop into appropriate gear when I need to roll again. (I drive to save gas, you could say. Until I find a job to fit my schedule that is)
It's just different styles nothing wrong, I do agree all drivers should know how to heel-toe. For me it's a technique for racing, fun, and even emergency maneuvers

Enfynet

I can't effectively "heel-toe" as my right foot heel gets in the way of me using the clutch, and I'm not that flexible. I'm better off twisting my foot towards the brake or gas...

JM2005

There is no need to "double-clutch" in todays cars for everyday driving, and only a very few cases during a road race course.
Now if your driving it like a heavy duty truck, well then have at it...otherwise its just alot of wasted motion with nor real beneficial gains.

Louie

I'm driving an automatic

Whitestang06

cop on my back

I have tried to heel toe my 05 during autocrossing events and on the street and with the throttle by wire it is impossible. The throttle will not respond to a blip of the gas pedal.

You have to hold the throttle down about twice as long as you would with a throttle cable to get a response. I guess I could try to do it more, but the TBW just pisses me off.

Rampant

You don't [have] to use your heel and toe. If you have big, wide feet (like I do), you can use the left side of the foot (in a vertical posistion) on the brake, and roll it over to use the right side of the foot to blip the throttle.

(though I don't have my S197 yet and haven't tried it on these cars, that is how I heel-toe on all the other cars (even SN95s when braking hard enough).