So can someone inform me as to the benefits of double clutching, I'm not a drag racer Just want to ease the stress off my clutch and get a bit quiker smoother ride. oh and an explanation of ho to is good as well...

 

there have been several posts explaining the techniques, also check out http://www.turnfast.com/tech_driving..._heeltoe.lasso

As to advantages/disadvantages:
- rev matching will be easier on the clutch disk.
- double clutching will be easier on the synchros, but more work for the clutch (twice as much, duh!)
- both will increase smoothness.

 

Hey thanks, I'm relativly new to racing tehiques... Actually I'm relativly new to most of the performance upgrades and such... trying to get there...

 

Double clutching won't take any stress of your clutch, in fact it will increase it. You use the clutch twice as much, as the name suggests. It will save wear on your syncros though, but IMO double clutching is really not necessary on modern cars.

 

You do not want to use either Heel and Toe or Double Clutching for Drag Racing... both are for downshifts.

Edit: Guess this didn't answer the question. I believe Double Clutching was used before Syncros were invented. No need for it anymore for the most part.

Welcome to the Abyss of racing... say "goodbye" to your disposable income.


[Modified by r2x, 3:47 PM 12/6/2001]

 

huh? why would double clutching wear your clutch twice as much. this is the first time i've heard this. clutch once as you shift to nuetral and clutch again as you shift into your next gear (down or up). clutch disk and plate engagement = once. as long as you rev match, your clutch will be fine. i thought double clutching was to save you syncros. have i heard wrong?


[Modified by ToneyTigre, 2:22 AM 12/7/2001]

 

Wow you guys really jump on he band wagon with some of your answers... I DON'T DOUBLE CLUTCH I heard about it and was just askin' but hey thanks for the help...

 

It's something like this.

double clutching, done while matching revs, spins up both the input and output sides of the transmission. This keeps the syncros from having to spin up the input side of the trans.

The only time I see a benefit with it is when you shift from 2 to 1 like in an autocross. In this situation the input and output shafts are turning at much different speeds...the syncro has to do a lot of work to match them and allow the car to go into gear. I suspect that my habit of *not* double clutching my 2-1 shifts is why my 1st gear syncro is a bit tired. OK, a lot tired.

 

Rev matching is what I should focus on then (that is to be a quicker nicer driver) nicer to my car that is?

*again it's a question so lets not get nasty?

 

i used to double clutch all the time in the 454 dually with cattle trailer I used to drive, oh wait a minute we are talking about race cars. Sorry!

 

My school bus driver had to double clutch the dual axle bus we rode in.
it's was cool.... 10 spead bus!
big *** crown (looks like a twinkie)

 

Yes.

 

rev match = nice to your clutch
double clutch = nice to your syncros

double clutch while rev matching = good to both your syncros and clutch disk.

 

I'm setting myself up for getting "flamed " here but... Rev matching for down shifts or up? or C alll of the above. Reason for asking is I tried it a bit while shifting and it seemed like it put added stress on my car, instead of the normal loss of thrust when jumping from 4th to 5th it just continued at the same rate, but seemed as if my engine was struggeling a bit. down shifting is it even possible?

lets not burn me to bad on this one ok guys / gals

 

Double Clutch:

clutch in
shift to neutral
clutch out
rev (as needed)
clutch in
shift to gear
clutch out

Single Clutch with rev match:
clutch in
rev
shift to appropriate gear
clutch out


Half the use of the clutch on the second case. Wear doesn't just include the clutch disk, there are other parts (bearings, pressure plate, etc) that get stressed or worn when you push the clutch pedal in.

 

Grimm,
downshifting only.

Since it wasn't clear what your interest is let me spell it out:
- for drag racing, don't worry about it. You only upshift. Nothing special needed
- for road racing (on a race track), rev matching is crucial on the downshifts so that you don't upset the car when braking for a turn, and so that you can be in the right gear when you need to accelerate out of the turn. Double-clutching is only necessary on a race car equipped with what is called a crash-box (a gear box without synchros) - or if you need to downshift into 1st (rare on a race track...)
- for autocrossing, rev-matching is essential, and double clutching can be very useful if you need to downshift into first gear.
- for street driving, rev matching will make you a smoother driver and easy the stress on your clutch - but is not needed.

Both rev matching and double cluthing can be done without having mastered "heel-and-toeing" but are not very useful in that case. Heel-and-toe refers to a technique whereby you are rev-matching while braking. You are using part of your right foot to brake and the other part to blip the gas pedal. That allows you to perform smooth downshifts while you are braking. Please check out the links I provided previously as most of your questions are answered there.

Also, I do not know why you are acting like you got flamed. No-one flamed you or even got remotely excited about your question. They were just trying to figure out exactly what you wanted to know, and attempting to supply you with useful information - which, by the way, you could have gotten by doing a search in the archives of this board, or even spending some time on the TurnFast site I linked. It has some very good information about performance driving and the techniques involved; not a bible by any means, but a good place to start.

Edit: And one more thing (maybe this is turning into a small flame, after all): Diane (r2x) had already answered your question about whether rev matching was for up or down shifting. The least you could do is read the answers to the question you posted. If you're not going to bother taking the time to check out the links we give you, or even read the freaking answers, don't waste our time.

hth.


[Modified by SJR, 9:49 PM 12/7/2001]

 

Again thank you for your help,
SJR, i did read all the replies, I did go to the links provided, the reason for my question do you use it for down and up shifting is there was nothing said about upshifting, i'd rather not assume and just ask more specificlly. I realize I wasn't flamed bad at all but was just throwing out a warning cause I'm very new to performance driving and the techniques that go along with it.
SJR your replies was mlst helpful and explained everything for me which is exactly what I wanted to know. i like to learn the uses of each technique and where they are applicable. doing a search yes, I apologize i didn't do that. Sorry for wasting your time that wasn't my intention. Thank you again.