My dad told me that you can shift without using the clutch in the power band without grinding gears. Is this true or is he just senile ? It may just not apply to newer cars because he is an old school dragster and doesn't know much about newer cars. Please humor me!

 

Nah it can be done. It just takes some practice, and you have to know your car pretty well. I myself wont even try it.

 

not worth it

 

someone will probably correct me if im wrong, but isnt that what double and triple plate clutches are for?

 

one of my friends powershifted at the track, ran a pretty good time, but that's why his tranny is now sitting in my garage with grenaded internals. use the cluth, thats what it's there for.

 

yea power shifting isn't a good idea and theres no point to doing it during daily driving unless you really want a new tranny. Its to small of a window which you can get that shift so if you miss bye bye tranny. I'd stick with the clutch unless you car is for track use only and you got money to spend.

 

I think you guys are talking about two different versions of "power shifting" here. One when racing and one when just driving normally. It IS possible to shift normally driving around the city without the clutch. You just shift it perfectly in the right rpm level and it'll just slip into place. My brother had to do this when his master and slave clutch cylinder failed and drove this way for about a week or two on his miata. Then theres the other version of "power shifting" you guys are talking about like at the track or when racing. That version is when you just apply the clutch and not letting too much, if any, gas off while quickly pulling it into gear. Both verions aren't good for your car but both are possible.

 

You pretty much summed it up. Shifting without the clutch can, in theory, be done without damaging the tranny, but the margin of error is very small. You've gotta rev-match very closely, and if the gear dogs don't line up quite perfectly (which you have no control over, and is sorta common with broken-in trannys) it can be a little rough. Remember, the momentum of the car is on one end of the gearbox, and the momentum of the engine is on the other.

Modern synchromesh gearboxes are made for more smoothness and fuel economy and don't have the massive power capacity of the older trannys. With the old trannys you could slap them around quite a bit. If you do that with your Maxima tranny (or any affordable car) you'll tear it up pretty quickly. As well, the old musclecar trick of cutting synchro teeth doesn't work either.

In summary, don't do it unless your clutch is damaged and you really have to. Even if you're racing, it's of very little advantage (the kind of advantage that is insignificant when you're racing in a car that doesn't require a $5k dogmission).

Regarding the use of the term powershifting, some people think that means using the clutch but using it very fast, and staying on the throttle. While that's less abusive than clutchless shifting, if you make a timing mistake it's going to damage stuff as well, and ultimately just as senseless.

Dave

 

Double and triple plate clutches are simply a way to fit more torque capacity in a smaller package. If it's an aftermarket setup, you do it so that it fits. If it's a stock setup, it keeps down the drivetrain rotating inertia. (Rotational inertia = resistance to changing the speed of rotating object; a 10lb 10" solid disk has a lower rotational inertia than a 10lb 15" solid disk.)

Double- and triple-cone synchronizers do the same thing, btw. They have become much more popular in newer gearboxes. Unfortunately the teeth are smaller and easier to damage, and they cost 3x-5x as much to replace as single-cone synchros. Just another reason to not shatter your stock gearbox.

 

I can do it but I don't do it.

 

Clutch it man....

 

i pretty much agree with evrybody else...ive never even heard of someone not using the clutch....i know when my dad used to race his old camaro, he would just keep the pedal to the floor and shift with clutch.

 

my friend does it around town in his S13 because he has a Nismo 9 puck and that thing will kill your leg after a while but as a result his syncros are functioning as well as previously.

 

Heres a vid of me shifting hard and fast while keeping car at full throttle, but still using the clutch.
http://media.putfile.com/0-to-90-shi...ng-off-the-gas
sorry for the re-post

 

If you only shift clutchless when the engine isn't loaded and on upshifts only, it's not bad at all. Just time it consistently and gently push the shifter into gear rather than smash it.

Most tranny damage occurs when people are trying to shift faster than normal.

Dave

 

My friends has told me about shifting without the clutch in his mustang.
Don't listen to dads! Mine insisted that my car didn't have spark plugs because it had fuel injectors. He is definately wrong. haha

 

Power shifting does not hurt the tranny if it's done correctly. All you have to do is aline the rpms of the motor and something else(flew outta my mind). It's actually good because you don't use the clutch so that stays in good condition. I have personally learned to up-shift and down-shift without the clutch but i honestly never do this on my car. (i worked valet )
If you know your car well you can do this by the sound of the engine aswell.

 

I think I'l stick with wearing the clutch and saving my gears.

 

You match the RPMS of the motor to what the tranni/flywheel? is spinning at. Its the same as rev matching accept your shifting and not using your clutch....I personnaly don't like the idea, maybe if it was a track only car or something. But that gains in speed are not worth the damage you will most likely do learning how to it considering this is a daily driven family car....

 

Clutch = $121.

Tranny Rebuild (DIY) = $400 minimum.

The math disagrees.

Dave

 

The Splines

 

Talk to a truck driver (Tractor Trailer). They do clutch less gear changes all day! My uncle told me about it, and then proceeded to do it on my Max, a Honda, a Vette (68) and an old Triumph. I guess he just wanted to show that it could be done on just about any manual. He wasn't hammering the gas, either. I've tried it, and would use it only if necessary (and to show off to friends that it can be done). Best to practice on flat ground and this is for normal driving (not "speed shifting" as in track racing). Pull off leisurely in first to about 2.6 grand. Come off gas easily, as car is starting to decelerate, at around 500 RPM drop, pull lightly from first to second. Don't force it or you'll grind em! Aside of being a cool trick, it's slow as Hell and even when proficient, you'll still get honking behind you to move out the way. I've done it from first to fifth, but again...Just for show. Power shifting while racing I've tried once (not on my car). Hit the red line and ****** away.

 

if you know how to drive a stick and shift it properly and quickly, it will be betterthen any type of power shifting. When i was 18 i did that to a 2000 jetta 1.8T...i slammed it into 3rd and it didn't want to come back out, 30 min later the tranny fell apart in front of my house(my neighbors car, she was on vacation). Yeah, i'll never ever treat a car like that again. Anything front wheel drive, u have to be easy with the shfter. When u have something like a mustang and the shifter is bolted directly to the tranny, yeah, u can slam it a little harder, but that's it. it's like slaping your wife, she ain't gonna like it and you'll have to pay for it later on(i don't have a wife and don't hit women LOL)

 

i used to shift like that all the time in my old 85 nissan 720 pickup with a shot transmission. it was kinda fun lol.

 

I've done it on my GSR before...but then my clutch was already quite messed up. After it got stolen and taken for a joyride....I can't even shift w/ the clutch. I had to start the car in first gear in order to move =X