lets talk double clutching.

Autox, road racing, etc
User avatar
M20_fever
Größter Vorsitzender
Posts: 11026
Joined: Fri Feb 27, 2009 1:28 pm
AntiSpam: No
Location: Northern IL

lets talk double clutching.

Postby M20_fever » Mon Apr 11, 2011 3:29 pm

I'm trying to learn how to double clutch and heel toe, and from what I'm learning the double clutch process goes something like this:

clutch in
Shifter into neutral
Clutch out
Rev match throttle blip
Clutch in
Select lower gear
Clutch out

Now my question is, why do you need to let the clutch out in neutral? It seems to work fine just holding the clutch in while rev matching and going right from higher gear to lower gear. What is the need/purpose of letting thx clutch out in neutral?
Image
Midwestern Councel C Prepared class champion 2012
North Suburban Sports Car Club C Prepared class champion 2012
HSAX Instructor

GET YOUR E3P GEAR HERE: http://www.cafepress.com/e3pgearshop
User avatar
Yoshi
Site Admin
Posts: 9086
Joined: Thu Feb 26, 2009 7:47 pm
AntiSpam: No
Location: North VA
Contact:

Re: lets talk double clutching.

Postby Yoshi » Mon Apr 11, 2011 3:55 pm

double clutching was useful when transmissions had no synchronizes. Putting the car into neutral once made all the shafts of the trans spin at the same speed. While if you shifted from one gear directly into another, the shafts need a bit to match speeds before they will mesh. Otherwise, you'll grind the gears.

There is no reason to do this in a modern car. Some big rigs require this and some lawn mowers. That's about it.
Image
Status: HG repair. 488wtq though!
User avatar
M20_fever
Größter Vorsitzender
Posts: 11026
Joined: Fri Feb 27, 2009 1:28 pm
AntiSpam: No
Location: Northern IL

Re: lets talk double clutching.

Postby M20_fever » Mon Apr 11, 2011 4:11 pm

Well, I know the history but from my research it is still very useful for getting around a track quicker. When you don't rev match you get that resistance on down shifts that slows you down. By rev matching you eliminate that moment of what is essentially engine braking.

So the purpose of letting the clutch out in neutral is to get all the shafts in the trans spinning at the same rpm, makes sense. I'm still thinking its just as beneficial to just get a good rev match and go from gear to gear. I guess rev matching is different than double clutching?
Image
Midwestern Councel C Prepared class champion 2012
North Suburban Sports Car Club C Prepared class champion 2012
HSAX Instructor

GET YOUR E3P GEAR HERE: http://www.cafepress.com/e3pgearshop
User avatar
Yoshi
Site Admin
Posts: 9086
Joined: Thu Feb 26, 2009 7:47 pm
AntiSpam: No
Location: North VA
Contact:

Re: lets talk double clutching.

Postby Yoshi » Mon Apr 11, 2011 4:28 pm

it's simpler to just rev match. Plus if you drive your car right, it shouldn't matter.

I've seen no real modern race car where the driver double clutches. It's a useless skill to learn.
Image
Status: HG repair. 488wtq though!
User avatar
87e30
I <3 E30's
Posts: 2008
Joined: Wed Oct 27, 2010 5:25 pm
AntiSpam: No
Location: New Jersey

Re: lets talk double clutching.

Postby 87e30 » Mon Apr 11, 2011 4:45 pm

I always wondered what double clutching was ("always" being from the day the first Fast and Furious movie came out, cuz that was the first time I ever heard of it), but never bothered looking it up or asking anyone. Now I guess I know why I never heard of it, as it was used on older cars, before my time.

I totally see the purpose of rev matching. If you match you don't even need to single clutch though, nevermind double clutch. I was taught in my e21 how to drive without using the clutch at all, except to start out in 1st gear. Works for both up and downshifting. I've heard some people say that shifting that way will wear out your clutch faster, but how can that be possible if you're not using it at all? If the clutch pedal is fully out at all times, then there should be no wear at all. The only problem I can see is if you try to jam it into gear at the wrong RPM, but that would do damage to your tranny before your clutch.

A friend of mine showed me a video of heel & toe driving several years back. Looks like it takes a LOT of practice to master.
Schwarz 5-speed 87 325is (newest project)
Arktisblau 5-speed 86 325e (current DD)
Schwarz 5-speed 87 325e (parts car/LS1 swap?)
Gazellenbeige automatic 85 318i (70,000 miles)
Alpine white 5-speed 87 325is (my first e30, possibly for sale)
99 Suburban
User avatar
ten2doyle102
I <3 E30's
Posts: 5462
Joined: Fri Feb 27, 2009 5:17 pm
Location: Appleton, WI
Contact:

Re: lets talk double clutching.

Postby ten2doyle102 » Mon Apr 11, 2011 4:46 pm

Agreed, Double Clutching is pointless on the track in my opinion. Also, I think its just too much to think about while on the track. Left foot braking, smoother rev matching and heel-toe are probably more beneficial than anything else.

I have tried to heel-toe but my feet are too big....lol. I can't press the gas pedal down very well and hti the brake at the same time.
Image
User avatar
Yoshi
Site Admin
Posts: 9086
Joined: Thu Feb 26, 2009 7:47 pm
AntiSpam: No
Location: North VA
Contact:

Re: lets talk double clutching.

Postby Yoshi » Mon Apr 11, 2011 4:57 pm

I toe toe. *shrugs* works fine for me :)

Edit: heel toe only really works for pedals that aren't attached to the floor.
Image
Status: HG repair. 488wtq though!
User avatar
87e30
I <3 E30's
Posts: 2008
Joined: Wed Oct 27, 2010 5:25 pm
AntiSpam: No
Location: New Jersey

Re: lets talk double clutching.

Postby 87e30 » Mon Apr 11, 2011 5:05 pm

ten2doyle102 wrote:Agreed, Double Clutching is pointless on the track in my opinion. Also, I think its just too much to think about while on the track. Left foot braking, smoother rev matching and heel-toe are probably more beneficial than anything else.

I have tried to heel-toe but my feet are too big....lol. I can't press the gas pedal down very well and hti the brake at the same time.


I wear size 13 boots because I can't find 14's in any stores! lol

Left foot braking isn't that hard to master. Very useful too.
Schwarz 5-speed 87 325is (newest project)
Arktisblau 5-speed 86 325e (current DD)
Schwarz 5-speed 87 325e (parts car/LS1 swap?)
Gazellenbeige automatic 85 318i (70,000 miles)
Alpine white 5-speed 87 325is (my first e30, possibly for sale)
99 Suburban
User avatar
Yoshi
Site Admin
Posts: 9086
Joined: Thu Feb 26, 2009 7:47 pm
AntiSpam: No
Location: North VA
Contact:

Re: lets talk double clutching.

Postby Yoshi » Mon Apr 11, 2011 5:10 pm

I learned left foot braking on go karts.
Image
Status: HG repair. 488wtq though!
User avatar
M20_fever
Größter Vorsitzender
Posts: 11026
Joined: Fri Feb 27, 2009 1:28 pm
AntiSpam: No
Location: Northern IL

Re: lets talk double clutching.

Postby M20_fever » Mon Apr 11, 2011 5:14 pm

I dunno, it is still widely used in pro-racing. Here is a vid I found, lots more if you search:

http://www.youtube.com/watch?v=0j-3xIZK-Bk (can't get the youtube embed to work...)
Image
Midwestern Councel C Prepared class champion 2012
North Suburban Sports Car Club C Prepared class champion 2012
HSAX Instructor

GET YOUR E3P GEAR HERE: http://www.cafepress.com/e3pgearshop
User avatar
Yoshi
Site Admin
Posts: 9086
Joined: Thu Feb 26, 2009 7:47 pm
AntiSpam: No
Location: North VA
Contact:

Re: lets talk double clutching.

Postby Yoshi » Mon Apr 11, 2011 5:18 pm

that's a race trans though (straight cut gears). Very diff from your stocker. You personally have no use in learning it. Most race car drivers have no use in learning it. Why bother?
Image
Status: HG repair. 488wtq though!
User avatar
M20_fever
Größter Vorsitzender
Posts: 11026
Joined: Fri Feb 27, 2009 1:28 pm
AntiSpam: No
Location: Northern IL

Re: lets talk double clutching.

Postby M20_fever » Mon Apr 11, 2011 5:19 pm

not dead set on learning it, just want to learn anything that will make me faster.
Image
Midwestern Councel C Prepared class champion 2012
North Suburban Sports Car Club C Prepared class champion 2012
HSAX Instructor

GET YOUR E3P GEAR HERE: http://www.cafepress.com/e3pgearshop
User avatar
87e30
I <3 E30's
Posts: 2008
Joined: Wed Oct 27, 2010 5:25 pm
AntiSpam: No
Location: New Jersey

Re: lets talk double clutching.

Postby 87e30 » Mon Apr 11, 2011 5:31 pm

M20_fever wrote:not dead set on learning it, just want to learn anything that will make me faster.


Mount a jet engine to your trunk and only race downhill? :mrgreen:
Schwarz 5-speed 87 325is (newest project)
Arktisblau 5-speed 86 325e (current DD)
Schwarz 5-speed 87 325e (parts car/LS1 swap?)
Gazellenbeige automatic 85 318i (70,000 miles)
Alpine white 5-speed 87 325is (my first e30, possibly for sale)
99 Suburban
User avatar
Yoshi
Site Admin
Posts: 9086
Joined: Thu Feb 26, 2009 7:47 pm
AntiSpam: No
Location: North VA
Contact:

Re: lets talk double clutching.

Postby Yoshi » Mon Apr 11, 2011 5:37 pm

if you get a trans with straight cut gears, it'll be the only way you can drive it.
Image
Status: HG repair. 488wtq though!
User avatar
ten2doyle102
I <3 E30's
Posts: 5462
Joined: Fri Feb 27, 2009 5:17 pm
Location: Appleton, WI
Contact:

Re: lets talk double clutching.

Postby ten2doyle102 » Mon Apr 11, 2011 5:45 pm

So a trans with dog cut gears doesn't have sycros?
Image

Return to “Racing”

Who is online

Users browsing this forum: No registered users and 1 guest