Sajid

I feel sorta embarassed asking this but you guys have been pretty simple/dumb questions so here it goes.

What exactly is double clutching and in what cases/scenarios are you supposed to do it?

Operator

yo someone just posted a sweet page about double clutching and what it is and how to do it and all sorts of other fun driving techniques and tricks
<a href="http://www.turnfast.com/" target="_blank">http://www.turnfast.com/</a>
have fun!

nickhance

I think this is covered on the site I posted about yesterday.

Look on <a href="http://www.turnfast.com/" target="_blank">www.turnfast.com</a> under the "Driving techniques" section.

Basically double clutching is a way to preserve the life of the synchros in your transmission. By releasing the clutch between gearshifts, you allow the synchros in the transmission to match the speed of the drivetrain. If you rev the engine to match the rpm it will be in when you release the clutch in gear, you can perform a smooth transition between gearshifts without any jolt that you would normally exprience as the transmission/synchros force the RPM of the engine up or down.

Thats more of a technical description than practical application, but the technique is easy.

Step 1: Push in clutch and move shifter to neutral
Step 2: Release clutch
Step 3: I'm not sure if you have to do this, but I normally blip the throttle to match the RPMs I expect the car to be at when I engage the gear
Step 4: Engage clutch and shift into gear.

Hope this helps

PorscheG96

What I don't understand is why those idiots in TFATF criticized that guy for not double-clutching in the 1 mile race...it was just a straight line, I mean double-clutching the upshifts?? That movie takes the cake for sucking, big time.

ian

[quote]Originally posted by PorscheG96:
<strong>What I don't understand is why those idiots in TFATF criticized that guy for not double-clutching in the 1 mile race...it was just a straight line, I mean double-clutching the upshifts?? That movie takes the cake for sucking, big time. </strong><hr></blockquote>

Yeah we were watching that movie the other night and me and my friend decided they should have paid us as consultants on the script.

My favorite part is when he brings in the supra and when they take off the hood they act surprised that there was a supra motor in the car. Wow a supra motor in a supra, what are the odds......
I think some of the writers were doing a little too much of this

<img src="graemlins/drink.gif" border="0" alt="[cherrsagai]" /> <img src="graemlins/drink.gif" border="0" alt="[cherrsagai]" /> <img src="graemlins/drink.gif" border="0" alt="[cherrsagai]" /> <img src="graemlins/drink.gif" border="0" alt="[cherrsagai]" />

or they were a little to much like this

<img src="graemlins/c.gif" border="0" alt="[ouch]" />

your choice

Water944t

Yeah, that movie blew goat.

Although, I guess to some, who do not have a clue about what it means to drive a "performance" car, **** like light-up nozzles and fart-cans really makes the car "appear" to be fast and furious.

Too bad most of these llamas start turning white and grabbing the "oh-****" handles when I take them for a ride. I guess "rice" doesnt go faster than 120MPH very easily.

What I really love however, is the number of rice-mobiles that I have been seeing at the local shops, with blown engines.

Gee...do you think that maybe that 100-shot N0S was a bit too much for mom's stock Civic?
<img src="graemlins/roflmao.gif" border="0" alt="[hiha]" />

I always get a chuckle from the multitudes of Eclipse's, Neon's, Civic's, and other econo-boxes that rev me at red lights.

There seems to be a correlation between "performance" stickers and "dropped-on-head-as-a-baby" in my town.

bs

yeah, i remember when that line came on i felt compelled to explain to the rest of the people in the room what double clutching was and why you DON'T do it when upshifting. why is it that american mass entertainment feels such a need to make people stupider.

if you want to see that movie excpet not sucking go try to find the movie "taxi" it's in french but is available here and there on dvd with english subtitles... it's an equally stupid and slapsticky kind of movie except that their "racing" does not consist of people driving in a straight line and seeing who had the most nitrous in their tank. the protagonist drives some peugeot that transforms in a batmobile-esque manner into a race car.

i've actually only seen taxi 2, but i knew by the end of the credit scene that this was the version of tfatf created in a culture where F1 fills the role of our nascar.

i guess in europe putting neon lights under your car doesn't make it go faster.

Jonathan Martini

My impression was the double shifting was a carry-over from the days BEFORE syncros. It is absolutely true that double shifting can perform a smooth shift. I'm not personally convinced that it extends the life of the clutch because you are in fact clutching twice as much.

I wouldn't worry about learning to double clutch. I let the clutch a little slower when I want things to be smooth. I think it works just as well. Besides, my clutch is rubber centered. That baby is going to die soon no matter which way is right.

Learn heel-to-toe downshifting instead. Impress your friends.

--Jonathan

yarin

[quote]Originally posted by Jonathan Martini:
<strong>.

Learn heel-to-toe downshifting instead. Impress your friends.

--Jonathan</strong><hr></blockquote>

Exactly! I'm going to start one of these days, i usually rev match when i down shift, but i'm not on the brakes as in heel & toe. It is definetely very useful when autocrossing.

Jonathan Martini

There is one reason to learn double-clutching, racing transmissions don't have synchro's.

nickhance

I usually double clutch while I do a heel-toe downshift. I know you technically don't have to do it, but I don't want to break my habit and have to teach myself all over again ;-)

Ahmet

Double clutching is a term used to refer to 'double de-clutching'.

As explained previously, you match the speed of the engine to that of the drivetrain.

It's a technique derived from the days of racing transmissions with no synchros, but the objective was (and still is) to have the downshift completed smoothly for purposes of not breaking traction @ the drivewheels. Heel&toe is often used in combination with double clutching, since that's when the speed of the drivetrain is rapidly changing.

I'll explain how/when I double clutch (almost always in combination with heel&toe braking):

realize that the corner I will be braking for will require a lower gear to accelerate out of effectively,

start braking,

push in clutch and move shifter lever to neutral,

momentarily let out the clutch (de-clutch #1)

raise engine speed (for me usually about 700 rpm short of redline)by openning the throttle while still on the brake,

push in the clutch again,

move lever to the lower gear desired (at this point the engine rpm should've dropped to almost the exact rpm of the current drivetrain speed, which is significantly slower than last time engine/drivetrain were engaged) as you have slowed down since then,

let out the clutch (de-clutch --&gt;#2, hence the real name of the technique 'double de-clutch')while feathering the throttle. I usually catch the engine speed as it's dropping near the drivetrain speed,

at this point I'm probably going to roll on throttle coming off the apex of the turn.

It is very easy to do, and becomes second nature after a little bit of practice. This is how I learned to drive a manual transmission car years ago, and it's something that doesn't require any thought anymore, and correctly done it's quite satisfying. Very similar feeling to apexing a curve just right, if you double clutch using heel&toe into the turn at which the apex felt just right, it is even more satisfying. It's like hitting nothing but net from the 3 point line... It becomes MUCH easier with time, while remaining satisfying every time you do it right! Really much easier done than said!
Ahmet

Z-man

Heel and toe will save your tranny more than double de-clutching. The syncros in our cars are able to handle the pressure of not declutching.

But: it sometimes helps to double de-clutch when upshifting. Most of our cars have a notchy second, and double declutching helps. In the cold mornings, if I don't double declutch when going from first into second, I have a very difficult time getting into that gear. If I double declutch, it's no problem at all. I do that once in the morning, and by the time I need a 1-2 upshift again, the car has warmed up enough not to need a double declutch. So I guess the boys in TFATF have the same trouble with their cars, or have trannies without syncros!!
Try this sometime: you will see a smoother upshift into second gear!

Regading heel and toe: that is the best thing you can do to save your tranny when pushing your car hard. Heel and toe will not make you go faster, just smoother, and will keep your tranny around longer.

BTW: The term "Heel and toe" is kinda misleading: it's more like rolling on the ball of your foot to blip the throttle with the right side of the foot whist still holding steady pressure on the brake with the rest of your foot! So why is it called "Heel and Toe?" Back in the early days of automoblies, the brake and accelerator were switched: the accelerator was in between the clutch and brake, and a little bit higher. The driver would "heel and toe" by applying brakes with his heel, and blip the throttle by angling his foot toward the center of the car and reach the throttle with his toes.

Good thread: many differing opinions of double declutching and heel and toe.

-Zoltan.
<a href="http://www.pelicanparts.com/gallery/Z-man" target="_blank"> </a>

Jonathan Martini

Originally posted by Zoltan:
[quote]Good thread: many differing opinions of double declutching and heel and toe.<hr></blockquote>

I agree. Its good to see we discuss a topic, have various opinions, and share knowledge without any of the immaturity I see on some other boards. If anyone checked out that 30 page thread on the Altima board about brake discs you know what I'm talking about.

bs

hmmm... double-(de)clutching an upshift? so in that case, you would be on the gas, accelerating, disengage the clutch,let of the throttle, shift to neutral, re-engage the clutch, let the drivetrain slow down,disengage the clutch again, and comlete your upshift?? ok, i'll have to try that; i know that my 1-2 shift is kind of rough in the morning when she's cold. fortunately i am blessed with an awesome drive to work that i can often make without shifting back to first more than once or twice. (yes my drive to work starts with the sign from my avatar, except it's a "1 mile" one...)

so i checked out that turnfast web site last night, and their description of heel-toe includes even a picture showing the heel being used to actuate the throttle. are we all doing this wrong? I definately use the right side of my foot to hit the gas... my feet are too big to get my heel to that pedal, plus then my foot wouldn't be supported on the floor anymore. do "real" race car drivers set up their pedals such that the heel can be used on the throttle instead of the other side of the foot?