Everybodywildou

iTrader: (32)

Does this mean theyre gonna come out with a clutchless racing clutch kit?

LegionnaireZ

iTrader: (1)

i believe Ferrari already has... it's their F1 paddle shifting system... the buttons for upshift and downshift are located on the steering wheel, and the clutch is handled by the car... neato!

BTW i used to clutchless shift with my old beat up Suzuki Dirt bike... it was so old i don't even know the model it was... 100CC is all i know about it... my brother wiped out twice in one day and in both of those wreaks...tore off both braking mechanisms... so we rode with no brakes... lot-o-fun!

but no way would i shift like that in my Z... i work way to hard and pay too much money to be doing foolish things like attempting to clutch-less shift my car... thanks anyway...

Bananax

iTrader: (3)

In Stillwater. Are you an okie too?

simonfencer

If you match revs properly going up or down a gear pressing the clutch pedal isn't necessary.

Back in the mid 90's I had a Fiero GT that I rarely used the clutch pedal in once I was rolling. If the revs are matched the gearbox has no idea that the driver didn't push down the clutch pedal.

A reason to not use this method is that it can be hard on the shifting forks and synchros in the gearbox. If you don't have revs matched the metals bit bang together instead of sliding together. In my youth I was very hard on gearboxes and clutches, and let me tell you there is nothing quite like spending a weekend rebuilding a gearbox when you are 16 and would much rather be out driving...even if it wasn't a 350z .

Now, if you learn to double clutch and "heel & toe" (although in a modern car it is more left side of foot & right side of foot) you can have some real fun while driving.

Paul

ouch1011

You are putting a ton of additional strain on the synchros by doing this.

It can be done if you match the revs fairly close, but the whole time you are pushing on the gear shift before the gear engages, you are grinding away the synchros. From the sounds of it, the synchros in these transmissions aren't exactly rock solid to begin with.

But double clutching and heel-toe shifting is good for performance driving/downshifting, and not only is it fun and impressive to your friends, it will HELP your transmission.

microd

OK... I'm a noob... I hear a lot about rev matching to wheel speed. What the heck is that? How do you rev to match wheel speed? Sorry if that is a dumb question. I did an internet search and read some stuff... still not real clear though.

sry110

iTrader: (17)

Literally half the reason I chose the 6MT over the 5AT is the clutch pedal.

buho62

One time I did the same, I shifted without clutch on every gear, accelerating hard, downshifting, and yes, it grinded like s#!t on every try. The only thing is that I did this in a rental car. That lady should've given me the car that they agreed to give me when I called them to make the reservation!

simonfencer

Basically what you are doing is getting the gear you are going to (say you are shifting from 4th to 3rd) moving at the same speed for its ratio as the gear you are coming from.

Example (doubt the revs are accurate, but this is just to illustrate the point)

50 mph in 4th = 2500 rpm

50 mph in 3rd = 3500 rpm

You push down the clutch just far enough to get out of 4th, let the clutch up, blip the throttle (don't hold it, just blip it) to say 3800 rpm, push in the clutch (now the revs drop a bit) and shift to 3rd. Then release the clutch. If you have matched revs right you can almost release the clutch as quickly down shifting as up shifting. With practice you could drive around with a blindfolded passenger and they would have trouble telling when you where downshifting. An added bonus is that it looks and sounds cool when you have it right.

Zmazing03

iTrader: (9)

I've never tried shifting w/o the clutch, but C&D says you can do it very smoothly, "although Nissan does not recommend this technique". After 1st to 2nd gear, and don't engage the clutch all the way to the floor. I just put it down enough that it shifts smoothly.

LeMans 05

iTrader: (1)

Please, people, use your clutch. You have synchros for a reason. Clutchless shifting will kill them.
On a side note, of course it's possible on any transmission to shift by just rev matching. A couple of years ago on my old Integra, my clutch master cylinder went out while driving home from work. I made it across town shifting without the clutch. It's just not a recommended way to drive as long as you have a properly functioning car.

LeMans 05

iTrader: (1)

You are now wearing out both your synchros and your clutch. Congratulations.

simonfencer

Actually if you get everything right with out the clutch you are probably putting less wear onto the synchro rings or clutch components. After all, the synchros are designed to take the abuse of the revs not being matched and get the next gear properly aligned. And every push of the clutch pedal puts a bit of wear onto the clutch disc and the pressure plate springs.

If any one hasn't seen the internals of a gearbox (not just a picture in a repair manual, but a real live box) a look at one can be very educational.

bailey bill

How can NOT using the clutch increase the wear?

Clutchless shifting requires you hesitate until the 2 gears are actually fully "synchronized" (rev-matched) before they will mesh. No wear on the synchros.

It isn't something I would recommend as a regular routine (its a somewhat slow, precise process) but it can be easily done, and causes no problem whatsoever.

bill

Zmazing03

iTrader: (9)

He was flaming me for not putting the clutch all the way to the floor in every gear. Some how engaging the clutch not quite 100%, puts MORE wear on it then putting it on the floor?

As for the synchros, how does that increase wear? I'm not slamming it into gear, its going in nice and smooth and you can't even feel it so I guess its not being too hard on the synchros, is it.

bailey bill

First, lets get the terminology straight.

When you step on the pedal, that disengages the clutch, When you release the pedal (let it come back up) your engaging the clutch.

And yes, if partially engage, or partially disengage the clutch that will increase the wear. Almost all clutch wear occurs during that frictional state between fully disengaged and fully engaged.

But but really doesn't make any difference to the synchros.

bill

Zmazing03

iTrader: (9)

Not enough that I will have to get a new clutch 10,000 miles before anyone else. Its minimal. And how would that increase wear anyway? You say between fully engaged and fully disengaged is the most wear. Okay, so every time you put it to the floor, you go through that anyway.

bailey bill

Yes, every time youj engge or disengage the clutch, you momentarily go through the "wear cycle". But a modern clutch will handle literally millions of those normal cycles with no problem.

But if tend to engage/disengage the clutch incompletely, you increase the span of the wear cycle. And if you partiually engage the clutch, say to hold the car on a hill, you are dramatically increasing the wear.

As long as the 2 clutch faces are either fully seperated, (disengage), or competely pressed together (engage) this is essentially no wear. Wear occurs when one face is spinning at a different speed than the opposing face.

bill

Zmazing03

iTrader: (9)

Yeah I definately don't do that on a hill -- thats what brakes are for.

I just go down, probably about 3/4 and right back up again,- seemless, and its not in "the zone" (if you will) more than if you went to the floor. Just requires less leg movement, and in traffic, I try to avoid shifting a lot.

simonfencer

Actually the clutch (single plate) has 4 faces if I read your explanation correctly. The fly wheel (face 1) the fly wheel side of the clutch plate, the pressure plate side of the clutch plate and the pressure plate. The fly wheel and the pressure plate rotate at engine speed (they are bolted together), and the clutch plate rotates at gearbox speed.

For those of you that haven't seen a clutch up close before, imagine a brake disc, but with the brake disc being the ablative portion and the brake pads being metal encompassing the full brake disc. That is essentially a clutch. And the wear occurs just how a brake pad does, during the time when the ablatives and metal are moving at different speeds.

Multi plate clutches typically trade diameter for a slight increase in stack height, but with the same over-all (or higher too) friction area due to having more discs.