Double clutching

[viperx]

My point was that its slow either way... of cource I'm not fcuking stupid enough to do anything as retarded as that!!! I didn't say brake while cornering!!! read it again.



They would only clutch in once... Unlike us they're not stressed about gear box longevity, they're only worried about times.

For one thing, its not slow to heel-toe and double clutch provided you have had enough preparation going into the corner. If your foot is on the brake when approaching the next bend then why is it slower if you can fit the double clutch in at that time? And yes it is not too hard to fit double clutching in. Nobody told you to blunder into corners unprepared. Its a skill that needs to be practiced. And my point isn't even braking while cornering. Its the fact that you can't take your foot off the brake, go and do something and then brake again while applying a lateral force. You will upset the car's balance and in high speed situations, lose traction (ie. lost time), potentially even roll the car.

And secondly, they are worried about gear box longevity. You realise that in BMI a lot of the time they are not driving dog boxes. They are road cars being subjected to race conditions. If they weren't worried about longevity, don't you think they would be flat changing on the upshift all the time? Why clutch at all?

Thirdly, if they really are clutching in once, then they do not need to blip the throttle WHICH THEY DO. I thought I had established that blipping the throttle without releasing the clutch DOES NOTHING except waste a bit of gas. It DOES NOT match your gear speeds because the layshaft is not connected when you blip the throttle. Please do your theory...

Driving with mechanical sympathy is a skill. Driving fast is also a skill. That is why driving fast AND being mechanically sympathetic is hard.

[fueltank]

Thirdly, if they really are clutching in once, then they do not need to blip the throttle WHICH THEY DO. I thought I had established that blipping the throttle without releasing the clutch DOES NOTHING except waste a bit of gas. It DOES NOT match your gear speeds because the layshaft is not connected when you blip the throttle. Please do your theory...

haven't read the whole thread...but wouldn't blipping the throttle keep the revs up besides wasting gas?

[viperx]

It only keeps the revs up in everything up to the flywheel. So it's pretty much useless.... if you don't release the clutch, then blip, then clutch again, then your gearbox slows down.

[saboteur]

Do you guys that heal-n-toe have aftermarket pedals? I find it pretty hard to do in my car (throttle in particular), but in my mate's BMW the pedals seem to be in a much nicer position. It would be a great technique to learn for those track days.

Cheers,
Tim

[fueltank]

heel-toe is used to avoid abrubt weight transfer. If smoother shifts are what you're after, then double-clutching is the answer: put it in neutral then let the clutch pedal out (flywheel is now connected to the layshaft but not to the differential because it's in neutral) then give it gas until the layshaft is spinning at the correct speed for the lower gear, then QUICKLY push in the clutch, shift to the lower gear and release the clutch, all before the revs decrease. In most racing today, double-clutching is not used because syncros make it unneccessary and it would only increase shift times, but some people still like to practice it--mostly so they can add another driving skill to their repertoire.

[SIKCVC]

Thirdly, if they really are clutching in once, then they do not need to blip the throttle WHICH THEY DO. I thought I had established that blipping the throttle without releasing the clutch DOES NOTHING except waste a bit of gas. It DOES NOT match your gear speeds because the layshaft is not connected when you blip the throttle. Please do your theory...

You've obviously never heard of compression lock, which is a far bigger issue to a race company with $$$ to spare but not seconds. Without increasing engine revs to match road revs you will get compression lock at high RPM...

Theres more than mechanics involved...

You've established nothing except for the fact that syncros will slowly die if you dont double the clutch. and Flat shifting is far more damaging to engine parts especially considering the engines are under considerable load on accell compared with decel.

Its the fact that you can't take your foot off the brake, go and do something and then brake again while applying a lateral force. You will upset the car's balance and in high speed situations, lose traction (ie. lost time), potentially even roll the car.

Tractions not the issue here, if you attempt this at the same distance you would heel and toe your gonna end up off the track because you'll enter the corner too hot. Thats the biggest issue.

Heres a quick experiment... try and make your mouse tip onto its side by only applying sidewards force... its not gonna happen... center of gravity is too low. The arab drifters are the best way of seeing this in action (130-140km then full lock steering wheel in stock camry's, they spin about 4-5 times) The only thing that will change this is if you apply a strong enough force apposing the CofG at a lower point, ie hit a gutter.

If they weren't worried about longevity, don't you think they would be flat changing on the upshift all the time? Why clutch at all?

I've mentioned flat shifting... and in a lot of cases race drivers WONT clutch in on upshifts. They're skilled enough not to. I recomend anyone who has the balls/knowledge of their car to try it... its a peice of piss. Granted I'd never try it at high revs but it can be done.

And my point isn't even braking while cornering.

Just as a side note its only really FWD that you cant left foot brake in... its a commonly used technique in RWD's. That is where you balance a car around a corner with both throttle and brake.

sorry for the essay... a lot to reply to.

Edit: What Fuel tank Quoted is spot on.

[SiR JDM]

I read nearly eveything in this thread but I couldn't find anything about clutch ware....

The way i was informed (which could definatly be wrong so bear with me :P)
Rev Matching is the best way to preserve ur clutch, letting the flywheel and clutch spin at the same time causing the least amount of friction?

Similarly with Heal Toeing, I have a friend that heal toes every gear down ... Its a smoother ride.. i can vouch for that, but he also claims the clutch life story...

Is this true?

[SIKCVC]

its more for racing to prevent compression lock and to set the car up in a balanced power possition around a corner... as viperx has pointed out, its not great for your syncros so not something you should be doing all the time. unless your super fast and smooth at doubling the clutch during heal and toe.

Its an old line but it hasn't been mentioned.

Gears are for going, brakes are for stopping.

[fueltank]

Just as a side note its only really FWD that you cant left foot brake in... its a commonly used technique in RWD's. That is where you balance a car around a corner with both throttle and brake.

I think this is wrong.

[SiR JDM]

So do I... im pretty sure the eg6 does that in initial D...
proof right there :P

[SIKCVC]

I didn't want to try it since I have front bias brakes and apply brakes and throttle would meirly counteract eachother.

[viperx]

No, tell us what compression lock is. I've not heard of it before. as my understanding goes, most of the inertial load is after the flywheel, so pressing the accelerator to speed up everything before the flywheel doesn't do much anyway as when the clutch disengages the flywheel will be slowed down enough so that your initial blip doesn't do anything.

What is wrong with using the engine and drivetrain as an inertial load to stop your car again??

It's not clutch life Sir JDM, it's synchro life (and hence gearbox)