That is where I practice the single clutch blip - on the street making turns without stopping. I have never heard of double clutching with a blip, but I have been doing the double clutch without a blip on the street. I've found that the double clutch part doesn't have to be a full in and out, or at least I don't think so. It appears you can do a quick double jab as long as the shifter gets back in neutral during the process. Right now, I'm just not good at all with touching the gas with the side of my foot or the heel or the toe (tried it 3 ways), so either I'm not coordinated enough or haven't been taught the proper method.

 

I got long legs and short arms, so the optimal seating position in my evo is a compromise where the wheel is slightly too far away and the pedals are slightly too close. This makes heel toe more difficult, but a double clutch downshift with blip is no prob. I'd give my left nut for a telescoping steering wheel on the evo. Sigh.

Its not clear to me why you are double clutching if there is no throttle blip between the clutch events. Could you explain to me what you are doing?

 

Just aligning the synchros and getting used to the motion. How do you blip if you're not doing a heel-toe? I can only blip without heel-toe if I'm not concurrently ramming the brakes like on the track, but that's the whole point anyway - to perform this double clutch blip while threshold braking.

 

The double clutch downshift (with blip), no heel-toe is the fundamental maneuver. Let me define it.

double clutch downshift
clutch in, put shifter into neutral, clutch out, blip throttle, clutcch in, put shifter into next gear, clutch out

A DC downshift is the canonical way a pro driver does any downshift. There are times and places you dont do this, and drivers who have variations, but this is the starting point. Learn it accordingly.

You say you already know how to downshift in some other way? Tough noogies.
Now keep reading.

Sometimes you will want to downshift while braking at the same time. This means DC downshifting while braking, because ya know...DC downshifting is the standard way (see above). One problem arises:to do this you will need to be operating all three pedals (clutch, brake, throttle) at the same time. The heel-toe was invented so you can do this with only two feet. In other words, the heel-toe was invented so you can (DC) downshift while braking.

double clutch downshift while braking AKA heel-toe
apply brake pressure, follow normal double clutch downshift steps (above), relax brake pressure

Notice that heel-toe is just applying brake pressure during the entire time period you are also doing a DC downshift.

Imagine doing this on a road course. Using the "toe" of your right foot to apply the precise hard brake pressure, carefully modulated, while the "heel" of the same foot is blipping the throttle in time with the left foot modulating the clutch.
Don't let the blipping action of your heel disturb the brake pressure your toe is applying! Sounds pretty hard, huh? This is what pro drivers do. Even the ones that don't do this, or do a variation, would agree that this is the standard way to do it.

A DC downshift while braking is the canonical way a pro driver would downshift while braking. There are times and places you dont do exactly this, and drivers who have variations, but this is the starting point. Probably a good idea to learn this too.

Don' t make me break out the quotes from my book again to hammer this point home. (see my prev post).

The obvious way to learn all this is to learn to "DC downshift without braking" first. Practice for all the different gear changes of interest (5 to 4, 4, to 3, 3 to 2, 4 to 2). I suggest starting with 5 to 4 cause its the least agressive, you can do this all day long while cruising on the freeway, and its enormously useful for street/freeway driving.

I know you already know how to downshift. I don't care. Master this method anyway.

It will be useful to drive with someone who already knows how to DC downshift quickly and correctly. Listen to what a good one sounds like. This will tell you what you are trying to accomplish. It is possible to perform the steps as I describe above and do a downshift but not actually accomplish a "real" DC downshift. Please try not to practice this.

I know what you're still thinking. You're thinking "I said I already know how to down shift! Why the hell do I hafta learn how to downshift in this overly complicated way? Why can't I just skip to the whole braking and downshifting at the same time since this is the what I need to know!!"

Trust me.

Once you master plain old DC downshifting, start doing it while braking at the same time. Use your right foot now to press on the brake pedal and throttle at the same time, as necessary.

Aren't you glad now that you mastered the DC downshift normally so you can just focus on integrating the braking action? Sure you are.

Now that you've done all this work you can go back to single-clutching, no-clutching, quadruple-clutching, getting your gerbil-on-a-leash to clutch for you, or whatever sloppy/amazingly innovative/better than double-clutch but no one else has figured it out/personalized old methods you used and liked before. But now you do it out of preference, not incompetence!

This also means those Skip Barber instructors won't laugh at you.

For me, I found double-clutch downshift to be exactly what its supposed to be. Smoother and ultimately faster than the other stuff I tried. It also seemed to be the method my EVO's powertrain preferred by far.

 

I'm fairly sure that double-clutching without a blip, while in neutral, accomplishes squat (other than getting used to the motion).

If you actually feel a real result while doing this on the road, let me know, because otherwise I'm too tired to figure out how the absolute and relative speeds of the engine, input shaft and output shaft are changing as you do this.

By real result I mean that if you dont double clutch (no blip) you get a jerk but when you do double clutch (no blip) the jerk goes away.

-Peter

 

I'm still confused with one small thing...

I agree with what bhcevo is saying, however I still don't understand how double clutching gets rid of the jerk, I thought rev matching did that. (I'm talking about the jerk that happens when the clutch is engages with a disparity of speeds between the transmission and the engine). DC'ing DOES get rid of the very faint resistance when the stick slips into gear, but that resistance doesn't upset the car whatsoever because it's only "spinning up" the input shaft which has very little inertia... With a single clutch the synchros speed up the input shaft and clutch disk, so if the engine is accurately rev matched the two clutch halves are spinning at the same speed and you get no jerk.. But anyways...



Clay,
bhcevo is correct with practicing the basic motion without the braking involved. That's what I did to learn a single clutch downshift with heel/toe. Once you've mastered the double clutch technique by itself, then try it while braking. The only thing that changes is that you're holding the brake when you blip the throttle. Don't worry about threshold braking just yet, learn the motions first, and pushing everything harder and being more aggressive will come naturally.

If you're having trouble with the heel/toe motions I can help. I made a custom gas pedal "cover plate" and bolted it to my gas pedal. It has a slight flange on the left side which makes it much easier for my bigass foot to catch the edge of the gas pedal. If you want to hang out for a few hours on a weekend let me know and I can make one for you and install it. It immediately made a world of difference for me, especially when I wear proper driving shoes because I could never find the gas pedal with my right foot.. Let me know.

 

Wheelhaus, the short answer to your question is that you are correct, the DC technique bring the input shaft up to speed directly, without relying on the
synchros.

The single-clutch technique relies on the synchros to bring the input shaft up to speed, as you say.

The above difference, in theory, seems unlikely to be the cause of any jerk, as you say.

The long answer is that for whatever reason, i could never get single clutch to work smoothly enough for me.

In addition, pro drivers preferred double clutch, even while stating single clutch can work if you "blip longer". So it seemed unlikely their stated preference was solely due just to a historical lack of synchros in racecars.

Seeing as you got it to work smoothly for you, and the theory also supports your position, I guess the logical conclusion is that my technique was the problem.

I'd have to observe your own single clutch technique before I could definitively say my technique sucked, or yes that was as good as it got and I still wasn't happy with it.

I did work on rev matching with single clutch quite diligently, and then had immediately better results with DC, so I dunno.

Even when I could get single clutching to work smoothly, it seemed to take longer and didn't seem to be exactly what the powertrain was looking for, if you know what I mean.

I associated single clutching with "less smooth" from my own extensive/possibly flawed experience.

 

[QUOTE]What I'm currently unable to do PHYSICALLY due to lack of experience and coordination is to double clutch my downshifts with a blip while threshold braking.Hey Warr, it takes some time and practice to develop and be smooth, you'll get it . The double clutching technique (while simultanesly braking) described in previous posts was what I was taught at a Skip Barber Racing School....Double clutching (the open wheel formula style cars are race cars--no synchros--so you have to double clutch). I remember on the last half of the first day they had us going back and forth down the main straight at Roebeling Road Raceway practicing 4th-3rd, then 3rd-2nd (cars were 4-speed) for what seemed like hours! Its like second nature for me in the EVO now, and the pedal placement on our cars is perfect. It will really make a difference in your driving--you'll be much smoother once you get this down

 

ahh, ok I gotcha.. With your personal experience, you managed to notice an immediate improvement with DC'ing... I kept thinking to myself... "what the heck is this jerk he's talking about? I don't get it! argh!"

 

Maybe I see a light far ahead changing to red, clutch in, shift to neutral, clutch out, and I coast. I'm still coasting, going quite a bit slower by this point, and the light turns green, I blip the throttle, clutch in and shift into gear and accelerate. Is this still considered double-clutching since there is an extended delay between clutch out and clutch in? I always call it that but wasn't sure. I use this technique all the time when I see something far ahead that I will have to slow down for.

 

haha, yeah I guess so... It's basically the same motions but you're letting the revs drop (i assume) to idle. The general idea is that you're trying to eliminate wear and (as bhcevo would put it) "downshift shift as mechanically smooth as possible". you're still eliminating the synchros from the equation, and as long as you're rev matching accurately, I'd say yes.

Now just learn to do it faster while you're braking.

 

unless your transmission has no syncros, there is virtually no need for it.

 

thanks for the same info that's been posted 100 times already, if you'd have read the thread you'd understand why we're discussing it enev WITH synchros.

 

there is no reason to double cltch with syncros. there are other ways to rev match your gears that aren't newbie-rice-boy super cool sounding, and work more effectively without increased wear on the clutch.

 

could you please be a little more specific?