Look guys,


BS.... I've forgotten how to heal-toe downshift cause I never do it anymore. Here is where double clutching comes into play. Do 25 MPH in your Turbos in 2nd gear and try putting it into first. It's been a long time since I've driven a turbo so I don't remember but chances are there will be a 2-3 second period where the syncro gets the speed of first gear up to speed to engage. The harder you press, the harder the syncro works, the more wear.

I use double clutching simply because its equally as fast. The only thing is I probably wouldn't use it on the track because in a race car it would be a real *****. With a lightweight flywheel there is less inertia on the drive train which means two things. First, blipin' the throttle is super sensitive and requires more precision than a dual mass cause you have a longer period on the gas. Second, with less inertia, there is less resistance in the drive train. This is super helpful in rear wheel drive cars where inertia in the drive train and enable the rear wheels to break traction on downshifts. Less inertia saves your clutch too.

I drove a 360 Modena and I could barely double-clutch, it was almost impossible because the motor was so sprung. Probably be impossible in a CGT for me. I use double clutching in my street car simple because I drive like a freakin maniac and downshift every gear. It saves all the interals of my tranny.

Heal-toe is great but it doesn't prevent wear on your syncros. Think about downshifting by feathering the throttle instead of heal-toeing. That creates more wear on your clutch. Double Clutching prevents wear on syncros and clutch.

Edit: I'd like to make the point double-clutching is not neccessary in all applications or feilds of driving. I do it on the street simple to increase the longevity of my car.

I'll make a video in my Rolla S today.

 

Ken, the way I do it, I blip soon as the clutch is fully depressed and while blipping, I'm moving into lower gear. I'd only blip after the new gear selection if I've misjudged my braking point and have to delay briefly while I modulate the brakes to keep things smooth coming into the turn-in. Also, depending on the turn, I'm tranferring the left foot smoothly from clutch to brake (taking it over from left edge of right foot), feathering off brake and feathering on throttle to keep the chassis stability from being upset. I've heard some people swear by LF braking, some swear at it , but in certain tighter or decreasing-radius turns on some tracks, it allows me to keep pressure on the front longer for better turn-in, slide off line less and actually transition to throttle sooner, allowing exit at higher rpm--always a good goal. This was introduced to me by a successful racer when I started, and although I've tried driving without this technique to experiment, I feel more cofortable using it. I've double-clutched only when having to shift into 1st in an autocross years ago (don't AX anymore), but other than that instance, a well-executed blip after the clutch is depressed in H-T shifting, and during that transition to the lower gear is all I've personally done on track. My impetus is always to keep the chassis "quiet", so all of my footwork is oriented around keeping a balanced transition. Yes, I'm a big believer in trail braking too of course, so between that and my LF braking, I'd probably have some old-schoolers up in arms!

Btw, the LF braking can help quite a bit when you've aligned the car for optimized speed if it's a long-legged track but also has some tight, turny sections. Using LF to manipulate weight transfer smoothly on turn-ins can make up somewhat for non-aggressive camber and toe settings. There's always a compromise; you can align for handling and give up some on the straights, or you can align for speed and address handling in the tight sections by manipulating the car. I can't tell you how funny it is to hear someone ask me if I was LF braking out on track after walking away from them in a turny section. You sound like a VERY experienced driver, as does Life Dies and probably a lot of guys on here, so I won't say my way is "right" or "best", I'm just sharing input along with you guys.

 

When I double clutch which is basically all the time, I follow this procedure....

1- depress clutch
2- move shifter to neutral
3- release clutch
4- rev match to lower gear engine speed
5- depress clutch
6- slide shifter into lower gear
7- release clutch

When heel and toeing with double clutch it is...

1- brake and depress clutch
2- slide shifter into nuetral
3- release clutch
4- blip throttle with heel of foot while still braking
5- depress clutch
6- move shifter to desired gear
7- release clutch
8- off brakes for next acceleration

It sounds a lot more difficult then it is. Once you get it down, it is second nature. And the double clutching definately makes a difference with the firmness in which the gear is selected as previously stated.

 

I really don't understand why you have to release clutch and then rev match and then depress clutch again? Isn't that redundant and couldn't you just rev match while the clutch is engaged and already have or at least being shifting into the lower gear at the same time..or did I just explain heal-toeing?

 

Re-reading this thread, I want to be clear.....I am absolutely not some scmuck that doesn't know anything about heel and toeing and downshifting. I mean, most of us don't know each other besides screen names and thread posts!! Truth is, I have many, many years of track experience driving and I am constantly learning new things. Case in point.

OK, I feel better now.



Now, having said that, I am of the mindset that spinning up the transmission input shaft really serves no useful purpose other than quadricep development.

Will someone please make an argument that will cause me to rethink my normal heel-toe, rev matching, non-double clutching ways?????????

 

I never did understand that comment in FnF. If they were straight line drag racing, why would he need to double clutch at all? He shouldn't have been downshifting in the first place. Yet another example of that movie making import owners look bad.

 

With all due respect, I'm not sure how one can forget to heel-toe, and yet, proficiently be capable at double-clutching. Double-clutching while braking is basically heel-toeing with an extra set of clutch cycle thrown in while in neutral.

2nd to 1st is the only time that it may be useful... and even then, it isn't encessary... I used to auto-x, and never needed to double-clutch to go from 2nd the 1st... only heel-toed.

Syncros in modern gearboxes are meant to take the place of double clutching... sure double clutching helps to save the syncros, but tell me the last time that this was a problem in modern cars?

Cetaiinly, 99.9999999999% of drivers out there do not even nkow what double clutching means, and there doesn't appear to be an epidemic of syncros failures amongst manual tranny cars. Double clutching is simply not a necessity in any way with syncro'd boxes.

And I'd challenge anyone to double-clutch brake as fast as they can heel-toe. Heel-toeing, when done properly, is a very fluid combination of motions. It can be done in a blink of an eye. Double-clutching, as previously stated, is heel-toeing with an extra cycle of clutching...

I've watched countless hours sports car racing with foot-well cam... Best Motoring, Hot Version, Tiff Needell... not once, have I seen double-clutching used... it simply isn't necessary.

Of course... to each his own...

 

PS... I'm obviously comparing single-clutching heel-toeing to double-clutching heel-toeing... if that wasn't your point of comparison, then I've misunderstood your post...

 

Stephen,
Hoooorah!!!!
I am in 100% agreement.

 

+1

 

I double clutch so frequently, heal-toe is unnatural and feels out of place for me. Did I really fotget how to heal toe? You be the judge.

I think I said before its probably not the best idea for tracking a car as its completely unneccessary. If you are driving ***** to the wall downshifting to redline, double clutching is pointless.


Once again............... I'd like to make the point double-clutching is not neccessary in all applications or feilds of driving. I do it on the street simple to increase the longevity of my car.

 

I explained to "Life Dies" there is no need to double clutch a sychronized tranny he is not even old enought remember non-synchronized trannys'...it does nothing....

 

You're pretty proud. See the post a few above the one where you explained to me where I acknowledged it was used in non-syncro tranny's.

Need I say it again, I do it on the street. I simply inquired if a member had used to technique to put a car into 1st gear at 40mph cause it was the only logical answer. Now, it's a heated debate. Continue arguing all you want but I find mechanical-eroticia in double clutching.

With that said, GO BUY AN F1 tranny you panzies. J/K

 

OK Guys ... Here it comes.

You're all wrong. While Stephan Ti and others are dead correct, you're blip comes in nuetral when the clutch is engaged to spin up the input shaft, and it is debatable whether it is necessary, I still do it. But ... it's wrong.

Here is how the mega quick do it, and you're all going to owe me big for this.

1. release the throttle
2. when the pressure on the tranny goes away, pull the shifter out of gear (notice we have not touched the clutch). The shifter will pop right out of gear if you pull when the tranny load is released.
3. blip the throttle
4. depress the clutch
5. grab the lower gear

Boy do you guys owe me.

Now, if I can just get good enough at it to bring it to the track. The old way of double declutching was hard enough to learn well that it makes the new way even harder to adapt to.

 

Try that under hard braking and downshifting in multiple gears. You'll hear the linkage making "pop" noises as the lever doesn't doesn't release from gears under heavy load. One gear, yea thats fun. I don't understand the point of your post... And how was I wrong? Explain to me where I failed to understand what I have come to do so frequently...