stupid clutch question

[BostonNSX]

Hey I know this is kinda stupid question to ask . but it worry me a bit so I have to make a post and ask here..

for example.. at a red light , and I shift it to neutral, will pressing the clutch pedal all the way down ( disengage ) burn out or damages the clutch in any sense?

or at 1st g.. but press the pedal all the way down?

Thanks in advanced

 

[Vytas]

Keeping the clutch in (depressed) will put more wear on the throwout bearing. At a stop light, it's best to leave the shifter in neutral and the clutch pedal out (up). This method will put less wear on the bearing and will not increase clutch wear.

When a throwout bearing wears, it could become noisy on release. The throwout bearing is sitting right next to the clutch. To change it is essentially having a clutch job done. Keeping the clutch out and shifter in neutral will extend the life of the bearing so it will at least last the life of the clutch. If it becomes noisy and you can't live with it and your clutch is still good, you'll spend the equivalent of a clutch job just to change the bearing.

Using this method will save wear on the bearing as well as strain on your leg muscle.

 

[BostonNSX]

it will wear the throw out bearings more but not the clutch itself ? is that what you mean?

 

[jrehner]

Yes that is what Vytas means. There's another good reason to shift into neutral at a Red light and let off the clutch. If you did not have time to downshift coming up to the light (or like to save wear & tear on the clutch by not doing so), if you forget you are in a higher gear and start off from the light and forget that fact--then you will either stall or lug the engine...Of course if you don't habitually shift to neutral and you try to start off like you're in first gear, then you just race the engine and feel stupid.....

 

[Zuerst]

This is a bit off topic but, if I were to go in reverse and since the reverse gear is quick can I depress the cluth partially and vary the depression to control the speed at which I back up? Or is there a better/correct way?

 

[Joel]

Another clutch question:

When I'm getting ready to go from a stop, I depress the clutch, shift to first, rev the engine to 1000 rpm or so and keep it there, let out the clutch gently to get the wheels turning and then give it more gas. Does THIS wear the clutch out too prematurely? Is this the same as riding the clutch?

 

[Dan H]

This is a bit off topic but, if I were to go in reverse and since the reverse gear is quick can I depress the cluth partially and vary the depression to control the speed at which I back up? Or is there a better/correct way?

This is also called feathering the clutch. Its ok to do but ONLY if the revs are very low. Revving high like 3K and while riding the clutch will burn up the clutch.

 

[D'Ecosse]

Clutches (the friction plates) don't wear when either fully engaged or fully disengaged - it is only when it is "slipping" against the flywheel that wear is taking place.
I would say that what Joel is doing is wearing the clutch.

 

[Dan H]

Another clutch question:

When I'm getting ready to go from a stop, I depress the clutch, shift to first, rev the engine to 1000 rpm or so and keep it there, let out the clutch gently to get the wheels turning and then give it more gas. Does THIS wear the clutch out too prematurely? Is this the same as riding the clutch?

It depends. How long are you holding the clutch? I use to dis-engage the clutch very slowly when I first starting learning stick (doing it too slowly will always cause some wear.)

After a while, you get a feel for the engagement point and do it quicker. I usually let up the clutch fast up to its engagement point, hold it for .5-1 sec, then release all the way as I give it more gas. The quicker you do it, the less wear or so I've been taught. It took me a few drives to finally get to that point and now I can do it fairly quickly without even jerking the car.

 

[ncdogdoc]

Lots of people are against holding the clutch pedal down while stopped becuase of the throwout bearing wear. But since most of us only get 50k to 60k out of our clutches and most replace the bearings at clutch replacement, it is not really important.

Feathering the clutch really does wear out an NSX clutch faster, but also makes takeoff from stop smoother, so choose your poison.

 

[fkong777]

keeping clutch depress will lead to wear in not only the throw out bearing but the presssure plate.

throw out bearing wear will create tranny noise but pressure plate failure will lead to clutch slippage.

to replace pressure plate, one would just do a complete clutch job since it is the same in labor.

 

[jrehner]

I can't really describe what I do--I just do it. I think people who race their cars are more into reving the engine to get the proper revs for a faster takeoff and they think about it more and practice it more. I always believed that a nice smooth release of the clutch was best for all components overall--including the engine and tires...many people will adjust their clutches so they release more rapidly or more slowly depending on their preference. I like it where when I start to let up on the clutch pedal it begins to engage very quickly and fully--you technical people--don't you call it a short vs long throw or something like that??

 

[Vytas]

Maximizing clutch life

I came across this email from Mark Basch in my NSX database of emails and found this on maximizing clutch life.

--------------

From all the NSX clutches I have replaced, I can tell you that the average is around 45 to 50k. I have seem some go at 10K (several actually) and a few last over 100. This has already been stated here. What I wanted to add, is the simple way I teach my customers to get max life, if you can just remember one thing - the clutch only wears while the pedal is moving. The faster you get the clutch pedal off the floor and to 'rest' position, the less life you have used up. If you slide the pedal nice and easy, with plenty of matching throttle movement also nice and easy, you are EATING your clutch. Many people think that if the car moves away from a stop so nice and easy that you could hold a full glass of wine, this is a good thing. This is the worst thing. If the car jerks slightly because you moved the car away from a start nice and quick, this is as close to zero wear as it gets. The majority of clutch wear occurs when moving the car from a stop, so practice this most.

Changing gears should be instant, or as close to instant as you can get. You should practice matching rpms to road speed to the point where taking your foot off the pedal really quickly should cause no discernable change in the cars momentum. If your passenger can not tell when your foot comes off the pedal, you have maximized clutch life.

Mark

 

[Larry Bastanza]

I believe there is one other disadvantage to stopping at a light with the clutch depressed, especially if the car is in neutral. If the clutch is depressed then the mainshaft is stationary. If the transmission is in neutral and you engage a gear this is not good for the syncro in said gear if both transmission shafts are stationary.

Syncronizers are designed to work when moving, not when stationary. You may actually find yourself fighting to get into gear when both shafts are still.

Ever find yourself in the garage, and you need to move your car slighly, so you put it in neutral, move it by pushing it w/engine off, then try to go back into gear and it is tough to get it? Same problem, BOTH shafts are not moving.

If you keep the clutch depressed at a light, you should release the clutch (in neutral, to spin the mainshaft) then depress it again before engaging a gear.

Generally, I am not in favor of depressing the clutch for long periods of time under any condition. There is no "up side" only potential "down side".

My $.02.
LarryB

 

[jrehner]

Interesting--that info is all new to me--exactly how do you match the revs etc so that you feel no surge when shifting..Is it kinda like double clutching on the gas side where as you disengage the clutch, you continue to apply gas rather than letting up on the pedal?? I sure racers know the answer to this question...

 

[nsxtasy]

exactly how do you match the revs etc so that you feel no surge when shifting..Is it kinda like double clutching on the gas side where as you disengage the clutch, you continue to apply gas rather than letting up on the pedal??

Not really. It's more a matter of adjusting the revs so that they match the road speed of the car.

For an example, let's start with a stock US-market '91 NSX with a five-speed. The gear ratios, from the NSX FAQ, are as follows:

1st - 3.071
2nd - 1.727
3rd - 1.230
4th - 0.967
5th - 0.771

For a given road speed, the revs will be proportional to these gear ratios.

If you accelerate up to the 8000 RPM redline in first gear and you look at your speedometer, it will show that you are going around 45 mph. If you shift from first to second, the car will still be going 45 mph, but the revs will drop from 8000 RPM to 4499 RPM, because 4499 = 8000 * 1.727 / 3.071 If you let the revs drop to 4499 RPM and hold them there before letting out the clutch, you are matching revs exactly, and the car will not jerk at all.

Similarly, let's say you're on a two-lane highway doing 75 mph in fifth gear, and the tachometer says your engine is turning 3226 RPM. You approach a slower car and you want to pass him before the no-passing zone starts up ahead. So, you decide to downshift to third gear for the extra acceleration in the lower gear. You want to rev your engine faster so that it matches revs to the road speed. How fast should you rev it while the clutch pedal is pressed in, before letting out the clutch? Well, if you adjust for the difference in ratios between third gear and fifth gear, you will want to rev it to 5146 RPM, because 5146 = 3226 * 1.230 / 0.771 If you succeed, you will find that the car does not lurch at all.

It sounds very complicated when you hear these mathematical formulas, but if you pay attention to how you're driving, you'll quickly be able to approximate the number of revs without doing math in your head. With a stock '91, if you let the revs drop by around 40 percent when upshifting from first to second, and by around 25 percent when upshifting adjacent higher gears, you'll come pretty close. When downshifting, you will need to do the same thing, by increasing revs around 67 percent from second to first, and by around 33 percent when downshifting at adjacent higher gears. If you practice it, you'll find that you will soon be able to approximate the right number of revs just "by feel".

Look up the gear ratios for your own car and work some examples, then go try them out on the street!

 

[jrehner]

I had to print that out---LOL doesn't sound too good for gas mileage

 

[Zuerst]

Say if I'm going around 70mph at around 7600rpm in 2nd gear, is it ok to push the cluth in and let the rpm drop to around 3000rpm and shift straight to 5th (or 6th) gear?

 

[fkong777]

Say if I'm going around 70mph at around 7600rpm in 2nd gear, is it ok to push the cluth in and let the rpm drop to around 3000rpm and shift straight to 5th (or 6th) gear?

Yes that should be fine. why bother shifting thru all the gear if you are at your desired cruising speed.

 

[Joel]

I think we should have a section in the FAQ that address these clutch questions--present and past. I know I've asked more than my fair share of how to drive a stick shift.

Most NSX buyers (myself included) buy a manual to take full advantage of the driving experience. Problem is, these same buyers come from driving automatics most of the time. And with the clutch part and labor being so relatively expensive to replace, I can understand why it would be such a hot topic to discuss in order to prevent premature wearing. Otherwise, people would just drive the hell out of it and learn the hard way.

Just an idea.

 

[POWERED by HONDA]

Say if I'm going around 70mph at around 7600rpm in 2nd gear, is it ok to push the cluth in and let the rpm drop to around 3000rpm and shift straight to 5th (or 6th) gear?

From what I've read previously, this overworks your synchros... am I wrong?