Can someone explain the double clutch technique a little better for me: I keep practicing it but I swear it takes more time to shift which would put me behind if it was a close race. Also, what are the advantages of this technique? Matt :???:
<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Flipndabrd Can someone explain the double clutch technique a little better for me: I keep practicing it but I swear it takes more time to shift which would put me behind if it was a close race. Also, what are the advantages of this technique? Matt :???: <hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote"> I only use it for my cranky old 5MT Dual Range. Sometimes getting into 3rd is a pain (synchro shot) and I gotta double clutch to get it in. Also getting into 1st gear while moving sometimes requires a double clutch; especially in Low range. clutch in, shift to N, clultch out, throttle to match RPMs, clutch in, shift, clutch out. You are trying to match RPMs between tranny and engine so its a smoother shift. Benefits are that its easier shifting into 1st while moving and less stress on drive train for any gear. Wouldnt use it in a race unless you want to loose Not something you need to do all the time really.
If you let me drive your car, I can show you. I do it all the time while coasting down and ALSO during heel toe-downshifting. The only downside is you lose gas because you're always revv-matching by stepping on the gas pedal...the more you gas the more it eats gas. Here's a thread that I wrote about what's happening in the tranny when you double clutch. http://forums.nasioc.com/forums/showthread.php?t=550157
<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">Originally posted by RallyNavvie Or you could just forego the clutch and slam it home as hard as you can, it usually catches <hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote"> I do that to the KIA a lot.... I mean to her }
Fuji you got a great thread going there. The purpose of rev matching is to get the engine to match transmission speed. Its as simple as that; alot of people look at footage's of this in action and are confused, and tend to think its difficult. But really its not once you understand its purpose. I do it quite a bit when I'm RR and can tell you from personal experiences, I do it to save my transmission, by double clutching the shift is slightly delayed allowing the gears to lineup and the synchros to open up. When your RR the transmission speed is constantly going up and down and sometimes you will have a hard time getting into gear with just a single clutch, you can sometimes hear the synchro's grind a little. The trick behind doing the heel toe action is you really only worry about balancing the braking, slowing your car down enough to make your turn. As far as the engine reving up, all that matters is you get the rev limiter to bounce up as high possible without redlining it so that once you have finished double clutching and have gotten into gear the engine rev will match the transmission speed. So basically getting it up as close to redline the more time you will have to get into gear. Because I'm just a weekend RR and its difficult to keep an eye on the dash at the sametime while I'm trying to setup for the turn I like to double clutch and heel toe twice just to make sure. And another thing, you do all your braking and Double Clutching before taking the turn. Hope this helps! Enjoy. C Fancy footwork: http://www.teamsmr.com/movies/Footbox Small.wmv
Wow.. the petal action on that video was awesome. I don't think his RPM's dipped below 4000 the whole video. Just a recap: Double clutching is for downshifting into a gear that normally the syncro's won't let you, (or like). It gets them spinning so they mesh up with out trany harm. Heal toe is used in breaking situations while executing double clutching, like aproaching corners. All correct?
hmmm...I too am curious about this, I understand rev matching and heel-toeing etc. but why double-clutch, you can match rpm's without letting the clutch out in neutral. I don't get it.
correct me if im wrong but i think clutching in and rev matching only spins that gear/sycro that is engage while if in neutral it spins all the gears/syncro. looks kinda like the same concept to me except it spins more gears.
The point is to spin up the synchros in the tranny to ensure a smooth shift With clutch in the tranny is completly disenguaged. With the clutch out, even in neutral, the tranny is still enguaged... just not in gear.
I try to double clutch most of the time, but I was thinking as I was spending a thousand dollars on a new clutch... Isn't this going to wear the clutch faster because you're always making it grab a flywheel that would be spinning more than if you werent double clutching?
Gspot-you got a good point there, but I'd rather spend the money replacing my clutch rather than my tranny. From my understanding rev matching and double clutching if done right should not cause additional wear. I double clutch when I am just trying to get into first, so you should think its just for racing, I use it when ever I'm driving a car with a tough clutch or old tranny.
I double clutch downshifts quite a bit...and it's literally the only way to engage 1st gear when my car is rolling. Once you've done it for awhile it's second nature and doesn't noticeably take longer.
GSPOT: Double clutching will actually reduce wear. When done properly (no, just focusing on the brake during heel-toe is not completely correct, but it will do under normal conditions), the flywheel and tranny are spinning at the same speed. That is why you put the car in neutral when revving so the tranny it spinning at the same speed as the engine (actually you want to "over-rev" it a bit to account for the slowdown during the shift back into gear. Hard to explain without pictures... Getting it perfect is actually fairly difficult. By perfect, I mean shifting down a gear without upsetting the car at all. Revving too high wil result in a little surge from the car and under revving will cause engine braking until the speeds are matched.
So the clutch would be spinning at close to the same rate at the flywheel it would be grabbing. Makes sense to me. I do it on all my downshfits, but rarely my upshifts. I know how, it just doesnt seem as necessary. Also on a sidenote, Amsoil in the tranny makes a huge difference!
The same benefit is not seen on upshifts. During an upshift you are trying to slow down the tranny. As for gear oil, Iuse Redline in the STi and Motul in the RS. I agree that better oil helps.
<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Zola and it's literally the only way to engage 1st gear when my car is rolling.<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote"> That is for **** certain.
