I learned how to drive a stick shift on my own when I purchased my first car, which was a 1990 Isuzu Impulse. As is usually the case, things were a bit rocky at first, but I eventually found the 'sweet spot' which resulted in the smoothest transition between gears. I didn't do much experimentation after that.

About six years later I got myself a '97 4-Runner automatic. Nice, reliable SUV, but not much fun to drive.

Now I have myself a 2K2 6-speed maxima. My initial interest in the Maxima led me to this site which had much to do with my decision to go for the Maxima. Reading this site also made me realize that there's more fun to be had with a manual transmission than just finding that 'sweet spot.'

Maybe some of you folks can share your wisdom with us less informed.

Thanks!!!

 

After you master normal shifting, it is time to learn double clutching and heel-and-toe shifting.

"granny shifting...not double clutching like you should be" - The Fast and the Furious

http://www.driversedge.com/dblcltch.htm

 

alright just a question, from your little quote there. How do you double clutch in that situation? I don't see how that could possibly work, all it would do is waste if anything just power shift, double clutching is more toward down shifting. Maybe you could clarify this up with me??

 

double clutching is a technique that supposedly allows ur gears to catch faster... you clutch in.. shift.. and then release and clutch in again right after ur into gear and before u accelerate.. hard to explain really well online.. but i tried my best

personally.. i dont double clutch because i havent gotten down the shifting rpms on this car down pat yet.. gimme a few more weeks

 

Powershifting is bad on your transmission.

You can double clutch any time you need to downshift to a lower gear to get the RPM's up higher into the powerband. If you're running in 4th at 50 mph and you want to accelerate faster, you can double clutch into 3rd or even 2nd. To double clutch into 2nd, you clutch once, drop the stick into neutral, and release the clutch. Then pop the go-fast pedal to raise the RPM's to where they should be for 2nd gear at 50 mph. Then clutch a second time to drop into 2nd, release the clutch and floor the gas. Your RPM's will already be up in the powerband when you floor the gas, you won't get that annoying jerk, and you save wear on your transmission. It takes practice so that it is done in one smooth motion and you need to learn where the RPM's should be for a given gear at a given speed.

I hope this makes some sense, if not, at least I tried.

 

isn't double clutching unneccessary on today's modern cars?

 

http://resource.crx.org/performance_..._shifting.html

 

that is exactly correct. I believe in double-clutching only when downshifting. True race car drivers upshift without bothering with the clutch, it f**ks up the gearbox, but it'll last them the race.

 

Feel free to correct me if I'm wrong, but yes it's not 'necessary' because of the way in which synchronizer gears operate. However, double clutching can lead to reduced wear & tear and smoother downshifts. Since it gets the RPMs at the appropriate place easier/faster, its easier on internal parts and perhaps improves acceleration.

 

Want to shift your 5 speed like Pro? Read.

 

You could do the NEW popular thing and do a TRANNY swap to an AUTO

 

What's the point of releasing the clutch while in neutral? Back when I had a 5-speed, I would constantly rev up the rpms between downshifts, but I wouldn't release the cluth in the middle of the downshift. From 3rd to 2nd, for example, I would put the clutch in and downshift and at the same time rev up rpms to the correct speed so when I released the clutch it would be smooth. This seems like it would be a lot quicker, too.

Tony

 

Revving the engine up with the clutch out accelerates the engine, flywheel, and pressure plate up to the higher rpm. The clutch disc and the various shafts and gears in the transmission are still at the lower rpm. Since the synchros match revs within the gearbox it's the difference in rpm's within the gearbox and the magnitude of the rotating mass at the "wrong" rpm that wears out synchros. So while just kicking the gas as you go through neutral is better than nothing - that does reduce the amount of "wrong rpm" mass - it doesn't do a complete job. With a little practice double clutching takes hardly any longer and will let the synchros live longer.

Norm

 

here that have taken thier cars to the track have been using the double clutch method? I generally do not do it very often, but if I am going to drop say two gears and make a hellish pass I do, I can tell the single method is hellish on my tranny.

 

I'm with Tony...i don't bother releasing the clutch then depressing it again before i engage a lower gear. it is much faster to PRESS CLUTCH ONCE-DOWNSHIFT TO LOWER GEAR-REV UP ENGINE-RELEASE CLUTCH. There's no point to waste time lifting on and off the clutch. i'm able to do this smoothly and it's obviously quicker.

Derrick

 

The 4th gen can never lose!

 

I concur.

 

Thanks for all the responses. Hopefully more will chime in to impart their wisdom.

The double clutching stuff makes sense. The only thing I'm still not sure about is the clutch/throttle synchronization. When I'm driving normally, I first push in the clutch and lift up on the throttle simultaneously. Then I shift. Then I lift up on the clutch and push down the throttle simultaneously. What would happen if I did this while maintaining the same pressure on the throttle? My assumption is that it would not be a good thing.

From what I've read so far, it seems as though you cannot maintain a constant throttle pressure while engaging and disengaging the clutch.

 

Your assumption is good. When you disengage the clutch the load on the engine drops to near-zero. With constant throttle the rpm's will rise, and rather quickly at that. Not as bad as with a right-foot-to-the-floor missed power-shift, but if you're even a little bit slow getting the rest of the shift done (a likely situation, since the 5-3 and 4-2 downshifts take longer than the 5-4 and 3-2's, which in turn take longer than the 4-3) the revs will very likely rise above the correct matching rpm and the synchros will be working extra hard in the other direction (slowing down the input side of the gear train, clutch assembly, flywheel, crankshaft, etc. while under power instead of speeding up only the clutch disc and gearbox parts against only their own rotational inertia).

As far as the relative speed of *single* vs double-clutching, practice will speed up the double-clutch method to the point where the pause as you cross the neutral gate is all but non-existent. And since this is generally done in anticipation of requiring full throttle in a lower gear (as opposed to suddenly realizing "hey, I need 2nd gear RIGHT NOW!!! like occasionally happens as regards suddenly needing to use the brakes) a few hundredths of a second is rather meaningless. It's not at all the same as saving the same few hundredths on an upshift at the dragstrip.

Norm

 

I generally only double clutch when I'm about to dump into a lower gear. And if you shift from fifth gear while going about 60 mph to third gear you will feel the effects on your tranny, that is pretty much the only time I double clutch.

My question again: Do people at the strips, more specifically experienced racers, double clutch going down the quarter mile?

 

As previously mentioned, double-clutching is specifically a downshifting technique and it's useable for just about any downshift other than the case when you're just slowly guiding it into first from a <5 mph roll as you approach a stop (in which case idle rpm is about what you need anyway). It's not at all an upshift technique, since on normal upshifts the engine revs will drop naturally during a brief lift of the right foot.

At the strip, completely different techniques are used, generally at the expense of long tranny life (particularly the synchros). For example, intentionally not matching the upshift revs by keeping them too high for the next gear will add some effect of rotational momentum of the crank, flywheel, and clutch to the torque output of the engine and give you a brief "spike" in your acceleration trace (read slightly quicker times).

Norm

 

If you are very carefull, you can row through the gears without using the clutch at all

At certain points in the RPM range, the engine's flywheel and transmission's input shaft are spinning at the same RPM ... no need to use the clutch. Key is finding these shift points without destroying your syncros.

 

Ummmm, the flywheel and the tranny input shaft are spinning at the same rpm whenever the clutch is engaged and not slipping.

Perhaps you mean that for a given tranny output rpm there's a matching engine rpm in either a higher or lower gear that, if you can hit it cleanly, allows you to shift without using the clutch or grinding anything. Absolutely true, but it does require a certain "feel". It's a useful technique to know for the hopefully rare circumstance in which your clutch cannot be disengaged but you can't stay where you are. However, this practice can't be recommended for any other situation. Been there, done that, fortunately having to do so only 3 or 4 times in 2 different cars over not quite 30 years (which conveniently excludes the POS pickup truck that I first tried it out on).

Norm

 

i dun think double clutching would improve ur shifting if u dun have a short throw shifter.. cuz the stock shifter's throw is so long that double clutching would keep you in neutral longer than necessary.. am i correct?

 

Not really. Timing and coordination, which improve with practice, are far more important than developing faster hand speed. Having all or at least most of the shift linkage internal rather than like the sloppy external linkage found on most old domestic 3 and 4 speed gearboxes helps a lot, too (doesn't bind or collect dirt in the pivots or between the plates in the shifter). The shift lever in the Malibu in my sig is 12" or so long with several inches throw in the 1-2 and 3-4 gates, but it's no particular hindrance.

Norm

 

I asked my mechanic about double-clutching to save my synchro's. He made a good point, which is that although you reduce the wear on your synchros, you double the wear on your clutch slave cylinder... so if you think it's good to trade one kind of wear for another, I guess you could double-clutch.

Also, I must chime in about the shifting issue: I do not double clutch, but I do blip the throttle when I'm doing a fast downshift from 5th to 3rd (a common passing maneuver in my 99 SE). I can do it VERY FAST, much faster than my friend can double-clutch his 328Ci.

The shift is uncommonly smooth and fast in my car; I can't do the technique as well in other cars, and other people can also blip-shift my car faster than they can shift their own cars. If I had to guess what is happening, I would say that I'm starting the blip while the clutch is still partially engaged, and that brings the synchros up a little bit in time to make the shift fast.

It's probably still not as good for your synchros as a double-clutch, but it's extremely fast.

- rus

 

YOU DON"T NEED TO DOUBLE CLUTCH ON A FULLY SYNCHRONIZED TRANNY LIKE OURS IF YOU JUST REV MATCH YOUR DOWNSHIFTS. IF YOU HAVE SYNCHHROS YOU DONT NEED TO DOUBLE CLUTCH

 

After driving 4, 5 & 6 spds for over 25 years, gear changes become instinctive. Double clutching and heel-toe shifting is only required when really pushing it through a series of curves at very high rpms when there is no time between accelerating and braking. In most autocross and typical road racing there is a point where you can down shift while coasting or braking where sub second shifts aren't that important. I would not recommend that a beginner try to push a new car that hard in the first place.

 

rus -

Unless something's misaligned between the piston in your slave cylinder and the clutch fork I don't see slave cylinder wear as being much of an issue. I'd have expected him to mention additional throwout bearing wear instead. In any event it's lots easier and cheaper to replace either of those than to do a complete tranny overhaul for synchros.

Evidently you've got your timing down for that method better than your buddy has developed his double-clutch technique. All that's left to get to a double-clutch is a quick up-then-back-down motion of your left leg as the shifter passes through neutral. Full foot-off-the-pedal re-engagement is not necessary for the neutral rev to do its job. I'm pretty sure that I went through a similar sequence.

Clutch disc construction/condition may be partly responsible/to blame. As I recall, there's something called a marcel between the friction faces of the disc that could affect how much pedal travel is necessary for disengaging the clutch. And it won't be quite the same from car to car.

Norm

 

I'm not sure why anybody in a racing situation would want to double clutch when the same thing can be accomplished with a single depression of the clutch and use of the syncros which alrady exist in the transmission. Depressing a clutch twice can't possibly be done faster than depressing it once and since the trans syncros will allow the gears to change without double clutching you're wasting your time, which in a racing situation seems like kind of a silly thing to do. While double clutching MIGHT reduce transmission wear very slightly it seems unlikely that someone who is racing would be very concerned about such a matter.

Double clutching was absolutely necessary to accomplish a down-shift when transmissions didn't have syncros, why anobody would be bothering to do so in this day and age is beyond me.

 

I gave it a few tries and double clutching works VERY nicely on my car. My car has REFUSED to downshift into gears since new. Usually I'm only able to downshift into 2nd below 15mph and 1st only at 2-3mph, so I just leave it in a higher gear and bog the engine. Just pushing in the clutch twice before switching gears works most of the time.

Recently I've added a SMC STS which made it all a little worse, but the shorter throws are fun. On my way to work I fly off of a 50-60mph straight away, brake like crazy, then turn onto a lane that banks right/left/right/straight. Anyways, before the STS I could sometimes "blip" the throttle drop into second and take the "rally course" at about 25-35mph. After the STS I couldn't "blip" the throttle and drop into 2nd, until this moring. I was going to revert back to my stock shifter, but if I can get the double clutching down I may keep it.

I haven't tried it yet, but the 5th to 3rd shift is what I really need to practice. I hate the feel of the tranny when I clutch, floor the gas, shift to third, and dump the clutch. The shifter/tranny/car buck.

THANKS!

 

Shifting without the clutch is easy and can be done at ANY rpm, but it isn't really any faster than a regular shift and certainly isn't faster than a power shift.

To up-shift without the clutch all you need to do (at any rpm, speed or in any gear) is to back off slightly on the gas (to unload the transmission) which will allow the shifter to pull the transmission out of gear. Now gently but firmly press the shifter towards the next gear, initially it wont go in but as the engine rpm drops the transmission will get 'sucked' into gear. Obviously good timing is essentual but it's not difficult to do and when done properly does not harm anything. I can shift my 6spd. Max without the clutch and the passenger will have no idea I'm not using the clutch unless they happen to notice the lack of movement by my left leg.

Down-shifts are a little trickier but basically follow the same proceedure only after you've got it out of gear you have to hit the gas enough to get the engine rpm above where it needs to be for the lower gear. Now as you press the shifter towards the lower gear the transmission will 'suck' it into that gear when the engine rpm (which you just raised with a 'blip' of the throttle) drops to the appropriate point. Again not hard to do but certainly no faster than a regular shift.

This clutchless up and down-shifting is much easier to do on modern motorcycles (than modern cars) because of the nature of their transmissions which don't use typical syncros and instead use what are called "dogs" which work faster.

 

Even the best synchros have their limits regarding how much rotational momentum and rpm difference that they can absorb. Too much of either and you get accelerated wear (at best) or grinding (if the synchros were unable to match the shaft speeds before the gear started to become engaged. Synchros work by friction, and a finite amount of time is required for them to accomplish this task. Greater demands on the synchros mean the time duration of their inside surfaces experiencing sliding friction is extended. Or you grind. If you have a chance to look at the inside of a gearbox, this will become lots clearer.

At low rpm's the momentum and rpm differences are reasonably low as long as you go up or down one gear at a time. But running at 2 or 3 times the easy driving rpm range or downshifting two or more gears means that the required drop or increase in rpm's also goes up by at least a similar factor, since single clutching does not accelerate the clutch disc or tranny input shaft and gears.

Downshift speed in a road race environment isn't that critical, since you're typically slowing for a turn anyway. And it's not even entirely a matter of being quicker than a single clutch downshift. For most downshifts the time spent moving the shift lever from one gear position, through the neutral gate, and into the next position represents more time than it takes for a single-clutch operation, making it mostly a moot point.

Norm

 

That is EXACTLY what I do Double clutching seems to only slow me down with all that pedal pushing.

DW

 

(Sigh) That's me and several sets of synchros in unison.

Whatever . . .

 

me too

 

Then it's a complete waste of my time to mention the heel-and-toe technique for downshifting while braking?

Which, BTW, is something I can't do very well, but at least I'm willing to try.

Norm

 

No, no no. Heel N Toe is real good,even with today's manual cars. I've only done like twice though

When I did it, the transition from going down on power into the curve and bursting out with power out of the curve was better, but since I'm not well practiced in it, the execution was a bit clumsy. Besides, I have the stock pedals. Heel N toe with these pedals is haaaaaard. maybe I'll get a set of aftermarket fat pedals sometime.

I'll stick with the single clutch pushing blip throttle downshift method, though

DW

 

Agreed, heel n toe is good, but it's completely unrelated to double-clutching.

BTW, last night while doing 65 mph I went from 6th gear to 1st gear without a double clutch and there's no doubt it was faster. Needless to say I didn't actually release the clutch after I got it into 1st, but the point is I got the transmission into 1st gear very quickly without need of a double clutch. Of course not using a double clutch is likely harder on the syncros, but when I consider the number of times such a shift is necessary I'm not very concerned about the extra wear it will induce. Basically if I'm going to need to do such a radical shift (ie. something like 6th to 1st) the nature of the situation is going to be such that I'm gunna want the shift to happen as fast as possible, meaning, double-clutching ain't worthwhile.

 

Unrelated? Not really. Think about it.

Norm