[speedsatya]

Originally Posted by rtech

Why would you ride the clutch? The changes have to be fast, or you defeat the whole purpose!

Rt

no its on purpose.but u get so carried away in the process of changing ,that sometimes it happens .

[Gordon]

Originally Posted by rtech

if you bypass the clutch while shifting, it is only obvious that the wear and tear of the clutch will reduce

Originally Posted by Rehaan

This actually causes LESS wear on the clutch. If done PREFECTLY, there could be zero wear on the clutch while shifting

Well these posts have got me thinking. And when I say thinking, I mean thinking real hard. Now if some of you are thinking "how is that??! why doesn't anything happen to the clutch?? its in the car and anything that you do not use is surely gonna get some problems later". Let me try to help you understand this. The clutch is the ONLY means by which engine power is transferred to the transmission. Without this your car would never move at all.

Now lets get this straight, when the clutch pedal is pushed down, the clutch is disengaged, i.e., the transmission of power to the gearbox is completely stopped! When the clutch pedal is not pressed, the clutch is engaged and thus the power from the engine is transferred to the gearbox.

When the clutch is engaged [clutch pedal is not touched], the clutch plate is tightly pressed on the flywheel and is locked there. So if the engine revs, the clutch plate would also rotate at the same speed. Most clutch plate wear n tear occurs when there is slipping between the flywheel and the clutch plate, i.e., when they are at different speeds. So if you never disengage clutch [push the clutch pedal], the clutch plate would always be in contact with the flywheel and there is no slipping between them. No slipping, so less wear n tear.

Your clutch surely will be a little more safe, but you can't say the same for your gearbox! You are surely going to risk damaging your gearbox. Your gearbox is going to go through hell because of all the "action" you're taking it through. If not done properly, and accept the fact that YOU* are not gonna get rev-matching even 80% right, forget 100%. So of course your gears are surely going to grind. So its worse. You'd save your clutch but would lose your transmission.

* that "YOU" was not meant for any specific person

PLEASE CORRECT ME IF I AM WRONG!

[Rehaan]

Yepp Gordon,

I think we have aldready established that using the clutch makes sense for driving "our" cars. Just that revvmatching will reduce the wear causing "slipping" between the clutchplates when they meet (when the clutch is engaged) because ~both the plates will be at similar speeds when they meet.

cya
R

[Gordon]

Originally Posted by Rehaan

Just that revvmatching will reduce the wear causing "slipping" between the clutchplates when they meet (when the clutch is engaged) because ~both the plates will be at similar speeds when they meet.

Hey Rehaan,

I didn't understand what you just said. During revvmatching [when you are not disengaging the clutch], the clutch plate is already in contact with the flywheel. Which two plates are you talking about?

[Rehaan]

Gordon,

Basically put, revvmatching could be termed as matching the RPMs of two rotating parts (one driven/powered(by the engine) and one to be powered).

In the case of revvmatching without useing the clutch (ie clutchless shifting) you are matching the RPMs of the rotating parts in the gearbox before you engage them with each other.

The same way, while using the clutch for shifting you can match revvs so that the input and output of the clutch are at the same RPMs (and hence the discs) when you engage the clutch. This is what i was talking about in the earlier post.

Have i managed to clarify it?

R

[Rehaan]

Also, i just want to mention for the sake of other people reading this thread, that clutches are made to be used! so please dont ruin your transmission trying to save your clutch.

And also..... i would say (i guess)80-90% of the wear and tear on a "normally driven" car's clutch comes from making the car start from a standstill, which cannot be be worked around by any revvmatching method!

Also - of your concerned for your clutch, when you are "waiting" on an inclined road please do not "balance on the clutch"....use your brakes!

[Deeps]

Thanks rehaana dn rtech for clearing things up. I have one more question. I read on indiacar or cybersteering that one should press the clutch while starting the engine even if the neutral gear is selected. This causes less load on the battery while cranking the engine to life. Can you guys shed some more light on this??

[Rehaan]

Originally Posted by Deeps

I read on indiacar or cybersteering that one should press the clutch while starting the engine even if the neutral gear is selected. This causes less load on the battery while cranking the engine to life. Can you guys shed some more light on this??

Hey Deeps,

That is correct. I have read something similar somewhere as well.
It said that pressing the clutch whilst cranking the engine can increase battery life by about a year or somehting like that.....
The only reason i could think of is coz of the extra weight the engine has to rotate when the clutch is engaged.... however that doesnt really translate to a huge difference IMO. Any other possibilities anyone? (Do note that cranking the engine is the most stressful of battery operated functions.)

However, i do always press the clutch when cranking up! -
1. Apparently increases ur battery life
2. Safer way to do it (incase u left the car in gear when cranking...)
3. Some cars require it

cya
R

[speedsatya]

Originally Posted by Deeps

Thanks rehaana dn rtech for clearing things up. I have one more question. I read on indiacar or cybersteering that one should press the clutch while starting the engine even if the neutral gear is selected. This causes less load on the battery while cranking the engine to life. Can you guys shed some more light on this??

now this is something new.
how can the clutch have any effect on the battery and the starting.
plsssssssss throw some gyaan on this.

[Deeps]

Originally Posted by Rehaan

Hey Deeps,

That is correct. I have read something similar somewhere as well.
It said that pressing the clutch whilst cranking the engine can increase battery life by about a year or somehting like that.....
The only reason i could think of is coz of the extra weight the engine has to rotate when the clutch is engaged.... however that doesnt really translate to a huge difference IMO. Any other possibilities anyone? (Do note that cranking the engine is the most stressful of battery operated functions.)

However, i do always press the clutch when cranking up! -
1. Apparently increases ur battery life
2. Safer way to do it (incase u left the car in gear when cranking...)
3. Some cars require it

cya
R

Some cars require it?? Like which ones? And i doubt that the battery life would increase by a year if only the weight of the clutch was involved. In any case, like you said, its safer to start with the clutch pressed.

[Gordon]

Originally Posted by Rehaan

Gordon,

Basically put, revvmatching could be termed as matching the RPMs of two rotating parts (one driven/powered(by the engine) and one to be powered).

In the case of revvmatching without useing the clutch (ie clutchless shifting) you are matching the RPMs of the rotating parts in the gearbox before you engage them with each other.

The same way, while using the clutch for shifting you can match revvs so that the input and output of the clutch are at the same RPMs (and hence the discs) when you engage the clutch. This is what i was talking about in the earlier post.

Have i managed to clarify it?

R

I already know what revvmatching is and I myself have already posted a lot of stuff on this. I didn't get confused on this.

Originally Posted by Rehaan

because ~both the plates will be at similar speeds when they meet.

I got confused about "WHICH" two "PLATES" you were talking about. Now I understood that the two plates you were talking about are the the flywheel and the transmission shaft.

Originally Posted by Rehaan

Also, i just want to mention for the sake of other people reading this thread, that clutches are made to be used! so please dont ruin your transmission trying to save your clutch.

Yeah thats right. I mentioned this too. Here is what I said "Your clutch surely will be a little more safe, but you can't say the same for your gearbox! You are surely going to risk damaging your gearbox. Your gearbox is going to go through hell because of all the "action" you're taking it through. If not done properly, and accept the fact that YOU* are not gonna get rev-matching even 80% right, forget 100%. So of course your gears are surely going to grind. So its worse. You'd save your clutch but would lose your transmission."

Originally Posted by Rehaan

And also..... i would say (i guess)80-90% of the wear and tear on a "normally driven" car's clutch comes from making the car start from a standstill, which cannot be be worked around by any revvmatching method!

Also - of your concerned for your clutch, when you are "waiting" on an inclined road please do not "balance on the clutch"....use your brakes!

Ya what you said is right. Most of the wear-n-tear occurs when the car moves from a standstill, because there is a lot of friction between the clutch plate and the flywheel.

Originally Posted by deeps

Thanks rehaana dn rtech for clearing things up. I have one more question. I read on indiacar or cybersteering that one should press the clutch while starting the engine even if the neutral gear is selected. This causes less load on the battery while cranking the engine to life. Can you guys shed some more light on this??

I don't know about this, but yes logically speaking, since the load of the clutch plate is released from the flywheel the load on the engine is decreased and may take lesser time to start thus saving power from too much cranking.

[Shan2nu]

Haha, it's been some 4 days and already this thread has reached places.

Anyway, like Rtech said, most of the time, it's all based on the type of transmission the vehicle has.

Some do it out of habit, or just for the sake of it, which serves no purpose.

Pressing the clutch does reduce the load on the battery while starting. But it would make more sense to talk in terms of number of starts gained rather than how many more years that battery will last.

One thing i don't understand is, if clutchless shifting is best performed at low rpms and at low speeds (as mentioned by someone). How can it be useful in a race? When i rip my car, i almost never see the tacho drop below 4000-4500 rpm.

I don't get the point. Why would someone let the revvs drop to below 4000 rpm just to use clutchless shifting?? If clutchless shifting is possible then it should be possible at any engine speed, if done right.

Shan2nu

[BikerSG]

I had only mentioned that clutchless downshifting on Bikes should only be TRIED at low revs and low speed as the bike would surge ahead.

clutchless downshifting on bikes serves no purpose.

Clutchless upshifting on bikes on the other hand is used by almost all bikers on the road, and by all bikers when racing.

[Shan2nu]

Clutchless upshifting on bikes on the other hand is used by almost all bikers on the road, and by all bikers when racing.

Can't argue with that coz i'm not a biker. I don't think almost all bikers on the roads use clutchless shifting.

Wouldn't that be dangerous as you wont be giving the engine enuf time to slow down, to suit the gear it is switching over to?

When i upshift really fast on my car (from 1st to 2nd and 2nd to 3rd at 7100 rpm), even with the use of the clutch, it makes the wheels chirp, which means that the engine is carrying way too much rpm for the selected gear.

On a powerful bike, that maynot just end with a chirp. If a MotoGP biker was to do that he'd end up doing wheelies in every gear (which is not the fastest way to launch a bike).

Shan2nu

[BikerSG]

When I say bikers, I dont mean commuters!

Bikers upshift clutchless, thats the only way to ride fast AND smooth. For downshift clutch is required.

I am not too aware of the technical issues (Maybe Gordon can answer this), but it has something to do with the bikes gear box being sequential. Same system as the big dragsters and some race cars also.