Austblue,
Close, you are heal/toe'ing, not double clutching. What the DC does is engage the flywheel, because the car is in neutral and the clutch is engaged. When you tap your accelerator, you are just spinning the engine, not the flywheel and driveshaft. Sot hesynchro still has to get the driveshaft at the same rev speed, you are doing this to a large degree when DC'ing!
I usually only use DC when entering very tight 90 degree corners which require a single or double shift down. I am not Schumacher, so rapid 6th to 2nd double clutches are beyond me, that is why he makes $50 mil a year. I agree that the heal-toe for most down shifts is preferable, try the DC when going into a tight right at a intersection, you will be able to feel the difference if you get the revs right, lots of torque at the corner apex, because your flywheel and driveshaft all have tons of rotational interia when spinning fast, maybe 3 times that of the engine and crank alone? Give it a try and have some fun swinging the rear out, Soyinside

 

Big Mike's shifts are all electronic.

 

Quick get my red pen! Soyinside, you're good on most of this but there are a couple of key things that are not quite right...Actually, Jason was exactly right a the post before yours when he said "isn't double clutching just pushing the clutch down once to pull it out of the gear then again to put it in the next gear?" This is used on cars without synchros such as really old cars and some race cars. What you've described is rev matching as you said. The point is to try and match the engine (which includes the flywheel, right? It's at the end of the crankshaft!) with the transmission/drive shaft which is now spinning faster than the engine. Check out this link for a detailed article: http://www.turnfast.com/tech_driving/drivi...g_heeltoe.lasso


Also being 6'-2", 230lbs I have to use the side step technique you describe and I'm getting better. You should stick with it.


[QUOTE][B]Most advanced driver's use these two elements to gain 10-20% higher corner entry speeds by reducing the available traction loss due to high amount of speed variance, usually due to simple downshifting. If you ever read a hi- performance driving instruction book, they talk about the "traction plot or circle" quite often. Basically you have a definite amount of traction available, when you use more traction capability on acceleration, you lessen the amount of turning traction available, and vise versa. Proper Double clutching technique increases the amount of "turning" traction you have available, by lessening the "acceleration" (whether braking, jerking or accelerating)

 

[QUOTE]Originally posted by johnnydev
[B]

 

very interesting thread!

what i usually do is the rev-match (w/o DC) when cornering, unless i have to skip gears (e.g. shifting from 6th to 4th, etc)

and i usually DC when i downshift (e.g. from 5th to 4th) to acelerate.

i almost never DC when upshifting (e.g. from 4th to 5th), unless i let the rev drop too much and i have to rev it back up again.

oh btw, my questions are:

the fly wheel is attached to the engine, right? so rev-match alone should bring the fly wheel up to speed?

DC is only used to save the synchros or used when there is no synchros?

 

Thanks Soyinside.

This is a good thread I've been wondering about this for a while.

Sorry to take it down a level but whats Vin on about in FF when he grills that other guy after the first race for "granny shiftin". Surely he didnt downshift (j/k)!

Now that I know that DC is in fact beneficial (even if only slightly), time to go practice!

 

I used to double clutch on my sentra SE-R since it really made a difference in shifting feel and effort. The S2000 tranny is so smooth that I've found it's just a waste of time. I do heal and toe almost every corner, but I stopped double clutching.

 

Ok, I am glad you guys are slick mechanically minded peeps! Yes, Mikey uses a 7 speed paddle shifter on his FI Ferrari, I was using a reference to back in the day when men were men, and actually had to slug the shifter though the gears instead of pressing buttons.
Yes, again, the Flywheel is connected to the crank, which inturn is connected to the engine, long day, my mistake. The DC will get the driveshaft turning, which in itself quite heavy and makes a big difference. I just went to a crosstown meeting with the top down, poor me, and tried the double clutch take off at 30mph in second gear, makes a difference, it gets you that 1/2 car length lead that might be needed in the end. The DC'ing sure makes a difference in driveline lash, and when you get it right, you barely notice you changed gears, just higher rpms's. Next meeting, we will need to hire H. Stookey to show us how to DC from 6th to 2nd in half a second, or any volunteer's, it would be a great tech session!!! Soy

 

Soyinside, I think you're confusing double clutching with simple rev matching.

 

we need CF drive shaft