How to extend clutch life?

[Edwardo]

Hey guys. I did a search on the forum on this topic. I also read the FAQ section. (Basic disclaimer to protect myself from the Forum Nazi)

I learned quite a bit about this topic. I am still a little confused about rev matching. I tried letting off the gas a bit before upshifting. Many times the Rev needle did not move after the shift(good right?). Many times, it did.

As I understand it, the point at which the clutch gets worn the most is when accelerating from a stop. I usually rev the engine from 1500 to 2000 rpm then let the clutch out gently so that the car does not lurch or shudder. Is that "riding the clutch"? Should I just let the clutch out quickly?

Thanks for any replies.

 

[Aiken Drum]

Okay, I'm in the process of figuring this out too. Sounds like you've got the in-motion shifting down. Here's what a friend told me that sorta helped me out with getting going from a stop without too much pain.

Basically, your engine is turning at the RPM you see on your tach. Your wheels are turning at 0 RPM. You want to reconcile the two numbers somewhere in the middle.

For a smooth start, keep the number on your (disengaged-clutch) tach as low as is comfortable (I seem to do well at 1200-1500 on my 1995), ride the clutch between the points of friction and engagement only long enough to get the engine rpm's down enough and the wheel rpm's up enough that you won't lurch, then let it engage fully and immediately accelerate.

The hard part, of course, is accelerating as you let the clutch engage fully, not before (takes longer to engage, causing more clutch wear) or after (stalling or shuddering).

I repeat though, I'm a newbie too, so this is just my experience doing what you're doing. I think some of this stuff is totally reflexive or intuitive for more experienced drivers, so sometimes they have a hard time remembering to tell you everything you need to do.

EDIT: I found this handy: http://www.howstuffworks.com/clutch.htm


[This message has been edited by Aiken Drum (edited 19 January 2003).]

 

[nsxtasy]

Originally posted by Edwardo:
I am still a little confused about rev matching. I tried letting off the gas a bit before upshifting. Many times the Rev needle did not move after the shift(good right?). Many times, it did.

Yes, that's the idea. If you rev match properly, the tach needle will hardly move after you let out the clutch. That minimizes wear on the clutch. As you probably know by now, it's a bit of a guessing game in figuring out what the revs will be after the shift.

Originally posted by Edwardo:
As I understand it, the point at which the clutch gets worn the most is when accelerating from a stop.

I'm not sure whether that is correct or not.

Originally posted by Edwardo:
I usually rev the engine from 1500 to 2000 rpm then let the clutch out gently so that the car does not lurch or shudder. Is that "riding the clutch"?

No, that's not riding the clutch. "Riding the clutch" refers to the (bad) practice of pushing the clutch in (even a little bit) any time you are not shifting gears. Unless you're shifting gears, you should not have your foot on the clutch.

Aiken Drum covered letting the clutch out from a stop pretty well.

 

[Vytas]

Here is a quote I kept in my personal NSX database from Mark Basch:

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 of 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.

 

[Lud]

Originally posted by Edwardo:
I am still a little confused about rev matching. I tried letting off the gas a bit before upshifting. Many times the Rev needle did not move after the shift(good right?). Many times, it did.

If the engine RPM changes when you release the clutch, you were off on your rev matching. This is not really a big deal, just keep practicing. You can probably same some small amount of clutch wear by proper rev matching, but this is not what causes the majority of cluch wear.

As I understand it, the point at which the clutch gets worn the most is when accelerating from a stop.

The clutch wears when it is partially engaged. Typically this happens when accelerating from a stop, as you describe below, but the act of accelerating is not what wears it - the act of holding it partially engaged is what wears it. The faster one side is moving relative to the other side while partially engaged, the more wear. Thus "feathering" the clutch while accelerating from a stop tends to be the major cause of clutch wear.

I usually rev the engine from 1500 to 2000 rpm then let the clutch out gently so that the car does not lurch or shudder. Is that "riding the clutch"? Should I just let the clutch out quickly?

That is wearing the clutch. Yes, you should let it out quickly. All things being equal, you'll need to give it more throttle earlier as you let the clutch out more quickly. Don't do the worst of both worlds - give it more throttle and still feather the clutch.

 

[NeoNSX]

this is interesting.

i was talking to a guy that's a driving instructor about "correct clutch use", and he teaches his students to let the clutch out slowly while applying the accelerator (also slowly). But what you guys are saying confirms what i always thought: this increases clutch-wear. (have i understood u guyz correctly?)

Stupid side-question: is there a point where you can release the clutch too fast and cause increased-wear? (eg. a newbie might pop clutch out after a gear change, THEN apply the accelerator?)
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[This message has been edited by NeoNSX (edited 19 January 2003).]

 

[nsxtasy]

Originally posted by NeoNSX:
Stupid side-question: is there a point where you can release the clutch too fast and cause increased-wear?

At the drag strip, perhaps?

 

[pok8rok8]

I believe as someone told me once is that two things can happen. If you let the clutch off slowly...you will reduce life of your clutch but will increase life of your transmission. If you let the clutch off quickly...transmission will wear faster. So I guess there is a fine line between the two. Im not much of an experienced driver so I cant say this is 100% correct. Hope someone can clear this issue to for us.

mike

 

[RacerX-21]

Also- don’t down shift to slow the car down. You will be saving the brakes while sacrificing the clutch.
Also- don’t brake without pushing the clutch in (Maybe in some race conditions).

Wear is an effect of friction, so little slip = less wear. But as mentioned earlier there is a threshold between fast/hard and slow/soft. More RPM or Pressure with the same time period of slip will equal greater wear, if graphed you would see intersecting curves between fast and slow (during acceleration).

The key would be little or no rpm change with a moderately fast engagement.

Unfortunately at high load I.e. Hard acceleration, or even upper speed highway use, most clutches slip some. That’s what I was taught in transmission class. Salt flat racers will tell you the same thing… that’s why they replace their clutches with super high pressure versions. These are basically on off switches.

 

[Lud]

For normal driving, releasing the clutch slowly doesn't help anything last longer (esp. the clutch!), it is just easier than doing it the right way.

You do not have to accelerate hard just because you release the clutch quickly.

"Quickly" does not mean you have to side-step the clutch or launch the car in your best John Force imitation. It just means don't hold the clutch at the friction point.

If you regularly launch your car by dropping the clutch at 3000 RPM and flooring the throttle, things are under a lot more stress and are going to wear out faster. This is just common sense.

 

[Edwardo]

Thanks for all of the responses. It looks like I will need to practice my launches. I think I habe been holding the clutch a bit long so that the car does not lurch. I hate stalling is why I error on the side of clutch wear.


I am going to just have to get out there on a less travelled road and get the footwork down.

Thanks again for the responses.

 

[sjs]

Originally posted by NSXEE:
Also- don’t down shift to slow the car down. You will be saving the brakes while sacrificing the clutch.
Also- don’t brake without pushing the clutch in (Maybe in some race conditions)...

The first point is generally accepted although the additional stress saved on the rest of the drivetrain may also be worth mentioning. (although personally I enjoy “rowing” the box both directions and my clutches still last double the norm). But I think the second is very misleading. There is no reason to depress the clutch every time you brake. For example, if while driving along at 60mph you need to slow for traffic, it's not necessary to depress the clutch unless you drop enough speed that a downshift is necessary, and even then it can be delayed until you make the downshift (short of lugging the engine of course). There's nothing wrong with letting the engine do a little of the braking under those conditions. In fact, to depress the clutch just because you apply the brakes will achieve the opposite of your desired results if you end up staying in the same gear.

I suspect you meant something different than the way it sounded, but it seemed important to clarify for those who are learning and might have taken it too literally.

As for the rest of the discussion, you need to ride with someone to fully understand the subtle nuances that make for significant differences in clutch life.



[This message has been edited by sjs (edited 20 January 2003).]

 

[NeoNSX]

Originally posted by pok8rok8:
If you let the clutch off slowly...you will reduce life of your clutch but will increase life of your transmission. If you let the clutch off quickly...transmission will wear faster.

this sounds like a "Damned if u do, damned if you don't" scenario. so which is more costly/difficult to replace?

NSXEE WROTE:
Also- don’t down shift to slow the car down. You will be saving the brakes while sacrificing the clutch.

Excuse my stupidly, but i don't get this... does shifting down put more stress on the clutch than shifting up?


Some of this clutch-stuff is contray to what i've been taught... and i guess my Driving Instructors mate teaches students the EASY way to drive (not necessarily correct).

I'm gonna have to practice my clutch now too... or if i can't be bother, it's time to buy an auto.

 

[sjs]

Originally posted by NeoNSX:
this sounds like a "Damned if u do, damned if you don't" scenario. so which is more costly/difficult to replace?

Don’t sweat the transmission. As someone already noted, short of serious hole shots you aren’t doing any damage by altering your launch technique to extend clutch life.

Originally posted by NeoNSX:
...Excuse my stupidly, but i don't get this... does shifting down put more stress on the clutch than shifting up?

A simple downshift will not cause more wear than an upshift if done correctly with rev matching. However, that assumes a single clutch action. When executing a downshift that will result in a significant RPM increase it’s best to “double clutch” to reduce wear on the synchronizers. Since that inherently means that the clutch is engaged twice rather than once, even skillful execution is likely to produce slightly more wear than an upshift. I say slightly because the first one into neutral doesn’t put significant load on it. In the real world few people will execute downshifts cleanly so yes, it will produce more wear than their upshifts. But the point is, don’t use downshifts to slow the car, use the brakes.

Originally posted by NeoNSX:
...Some of this clutch-stuff is contray to what i've been taught... and i guess my Driving Instructors mate teaches students the EASY way to drive (not necessarily correct).

He may be keeping it simple or he may not really be all that clear on the technical details of it himself.

 

[NeoNSX]

thanx SJS... u explained that clearly. thanks for ur time.

maybe he has stock-shares in companies producing clutches?

------------------
NeoNSX
Trinity: "What do we need?"
NeoNSX : "an NSX... lots of NSX's..."

 

[nsxtasy]

Originally posted by NeoNSX:
NSXEE WROTE:
Also- don’t down shift to slow the car down. You will be saving the brakes while sacrificing the clutch.

Excuse my stupidly, but i don't get this... does shifting down put more stress on the clutch than shifting up?

You're missing the point here. When you want to accelerate, you must do it with the gas pedal; you don't have a choice.

When you want to slow down, it's possible to do it by (a) using the brake pedal, or (b) downshifting and using engine compression to slow the car down. (a) is a lot cheaper because brake pads are designed for this function and are much more inexpensive to replace than clutches. Use (b) only for special situations, like when you're trying to nurse the car home from the track with cracked rotors.

 

[RPM217]

Originally posted by nsxtasy:
You're missing the point here. When you want to accelerate, you must do it with the gas pedal; you don't have a choice.

When you want to slow down, it's possible to do it by (a) using the brake pedal, or (b) downshifting and using engine compression to slow the car down. (a) is a lot cheaper because brake pads are designed for this function and are much more inexpensive to replace than clutches. Use (b) only for special situations, like when you're trying to nurse the car home from the track with cracked rotors.

Alright, so I don't have my new NSX yet, I'm still driving the corvette, I had a BMW with manual before that, and about 5 other cars all with manual transmissions. I like to drive a sports car (automatics just don't elicit the same feel). So I pose this questions to the forum, and to all of the experienced NSX owners out there, I enjoy downshifting going into a curve, and accelerating through the curve, are you telling me that I shouldn't do this with the NSX, maybe I'm buying the wrong car!! Either that or you guys are worrying too much about clutch wear. Oh, and by the way,while I don't track any of my cars, I drive them, and to this date, I haven't had to replace a clutch in any of them. Also, as a point of reference, the vette has 34,000, the original clutch, and brakes!!! Maybe I'm just a better driver than most, but I don't think so.

 

[stevefromatl]

Originally posted by RPM217:
So I pose this questions to the forum, and to all of the experienced NSX owners out there, I enjoy downshifting going into a curve, and accelerating through the curve, are you telling me that I shouldn't do this with the NSX, maybe I'm buying the wrong car!!

If you are downshifting to get more power to accelerate, then when you press the clutch in bump the rpms up before you engage the clutch. That way you will match the rpm's rather than putting the extra strain on your clutch.

 

[Soichiro]

RPM217 asked
>>I enjoy downshifting going into a curve, and accelerating through the curve, are you telling me that I shouldn't do this with the NSX, maybe I'm buying the wrong car!!<<

Downshifting for fun is allowed - it's the first step on the go-fast crack pipe. Downshifting to slow the car down is wasteful as noted above - use the brakes for this purpose.

 

[Optikal]

Originally posted by NSXEE:
Also- don’t down shift to slow the car down. You will be saving the brakes while sacrificing the clutch.

I usually match revs as I downshift. In city traffic, giving the car in front of me some room, and timing street lights I find I can use the engine to slow me down and no brakes. I've been doing this for years and my brakes still have a lot of life on them since 1998! Clutch still engages and can kill the engine without winding down slowly. So I assume my clutch is still good...

 

[NeoNSX]

Originally posted by nsxtasy:
You're missing the point here. When you want to accelerate, you must do it with the gas pedal; you don't have a choice.

sorry ken... i was tired writing that; i didn't make my question clearer.

i understand ur points (i think u have talked about this on a previous post i read). but in comparion, which causes more clutch stress? shifting up or down (matching revs). Or would it be just the same.

geez... i'm still tired... hope that makes sense..

 

[nsxtasy]

Originally posted by NeoNSX:
causes more clutch stress? shifting up or down (matching revs). Or would it be just the same.

I don't know. I do know that if you match revs, in either direction (up or down), there's less stress.

It may be easier to match revs when upshifting than downshifting, though, because (a) most people get a lot more practice upshifting, and (b) in upshifting the engine revs drop naturally when you take your foot off the pedal, whereas you have to blip the throttle to make them higher when downshifting.

 

[sjs]

Originally posted by RPM217:
... So I pose this questions to the forum, and to all of the experienced NSX owners out there, I enjoy downshifting going into a curve, and accelerating through the curve, are you telling me that I shouldn't do this with the NSX, maybe I'm buying the wrong car!! Either that or you guys are worrying too much about clutch wear. Oh, and by the way,while I don't track any of my cars, I drive them, and to this date, I haven't had to replace a clutch in any of them. Also, as a point of reference, the vette has 34,000, the original clutch, and brakes!!! Maybe I'm just a better driver than most, but I don't think so.

You'll be fine with an NSX, and you may well be easier on the equipment than the average driver. Many people today learn to drive on an automatic and pick up manual shifting only when they get a sports car. Others of us learned on a stick and have never owned anything else. I have ~85k on my '93 TT, more than half of which are by me. I drive hard and I enjoy shifting up and down. The original clutch is still solid, although even I am expecting it to fail before long.

I find that I make the transition from braking to turn-in much more smoothly if I have the downshift out of the way well before the corner, so when at the track or just playing on the back roads I double clutch downshift as part of the braking process, settle the car, then turn in. I've put a lot of years and miles on relatively few cars that way and never replaced a clutch that wasn't badly worn when I got the car. I think stock NSX clutches are much better than generally believed.

 

[Zuerst]

How do you drive a stick???

 

[TigerNSX]

Please check this:

Driving Lesson Video