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Re: Clutch life expectancy
I have an '06 C2S and I drive similarly to you so this may be a fair comparison. However, I have done a few track days and trips to the Ring. 
My clutch was still fine at 25k miles. The OPC changed it trying to diagnose a problem I was having but to no avail. So I think, 30k - 40k miles would be about right I'm guessing.
My clutch was still fine at 25k miles. The OPC changed it trying to diagnose a problem I was having but to no avail. So I think, 30k - 40k miles would be about right I'm guessing.
Aug 19, 2008 1:46:21 AM
- Silver Bullet
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Re: Clutch life expectancy
A clutch operated by a competent stick driver should last at least 75k miles - 125k miles is not unheard of. The keyword here is 'competent.' I read reports of 20k, 30k miles and obviously those people do not know how to operate a clutch (but they tell you they do, of course).
The current car I own with a stick has 80k miles on the odo and it's still going strong on its original clutch.
I read reports of 20k, 30k miles and obviously those people do not know how to operate a clutch (but they tell you they do, of course).
The current car I own with a stick has 80k miles on the odo and it's still going strong on its original clutch.
Aug 19, 2008 1:57:55 PM
- Atlas997
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Re: Clutch life expectancy
Gents, slightly OT, and I know this sounds like a basic question, but how do you "throttle blip" on downshifts. I know what it means, you can clearly hear it in cars where the drivers do so, but I just do know what foot/hand co-ordination and timing is needed to achive this.
The main reason I ask is because my downshifts have never been smooth and its something I loathe about my driving. I haven't figured out to smoothly downshift although its my understanding that throttle blip action can help.
If this question open too big a topic for discussion here then by all means direct me to links on the web the that describe how this can be achieved.
Aug 19, 2008 3:06:13 PM
- Leawood911
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Re: Clutch life expectancy
If you do not abuse it it should do 100-150K Miles easy. Starting from a stop is not as bad as slipping it on the highway from 5-6th at 70mph or so. Of course their is never any reason to slip it once rolling, just release and try to match the revs as best as possible.
I have owned 7 911 over 28 years continously, all of them used (and abused clutches no doubt) and I have never needed to replace a clutch. Most of my cars went well over 100K.
To think a 997 clutch would need to be replaced at 40K would be wrong in my opinion. Lastly, if you drive your cars everyday and do not let them sit the RMS will be much less likely to leak. The recent Excellence Magazine has a good tech reply regarding GT3 RMS issues and I believe this applies to the 997 and 996 as well.
Cheers,
Drive right
I have owned 7 911 over 28 years continously, all of them used (and abused clutches no doubt) and I have never needed to replace a clutch. Most of my cars went well over 100K.
To think a 997 clutch would need to be replaced at 40K would be wrong in my opinion. Lastly, if you drive your cars everyday and do not let them sit the RMS will be much less likely to leak. The recent Excellence Magazine has a good tech reply regarding GT3 RMS issues and I believe this applies to the 997 and 996 as well.
Cheers,
Drive right
Aug 19, 2008 4:31:37 PM
- 69bossnine
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Re: Clutch life expectancy
As others have mentioned, a clutch is easily good for 100K++ miles....
Aggressive driving has less to do with it than your driving style, the manner in which you achieve your up and downshifts with as little slippage and time possible... Once the pressure plate is clamped, you can hammer the daylights out of the car.... The clutch is engineered to having clamping power in excess of the car's peak torque, so you are not WEARING anything under full-throttle...
Where clutches die is in your habits and lack-of-technique when shifting...
Impossible to teach online, so I'll not try.
But if you get to 30K or 40K.... And your clutch is slipping and smelling....
You need to buy a PDK next time around...
Aggressive driving has less to do with it than your driving style, the manner in which you achieve your up and downshifts with as little slippage and time possible... Once the pressure plate is clamped, you can hammer the daylights out of the car.... The clutch is engineered to having clamping power in excess of the car's peak torque, so you are not WEARING anything under full-throttle...
Where clutches die is in your habits and lack-of-technique when shifting...
Impossible to teach online, so I'll not try.
But if you get to 30K or 40K.... And your clutch is slipping and smelling....
You need to buy a PDK next time around...
Aug 19, 2008 5:23:11 PM
- MMD
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Re: Clutch life expectancy
Your clutch should have almost "zero" slippage when going from a stop (assuming you're driving quietly and politely).
Yeah, yeah..., it's impossible to have zero slippage.
My point? When I start off from a stop you can't tell that my car is a manual by the engine revving; it's absolutely minimal slippage-wise.
My bet is a huge percentage of guys could get more service life out of their clutches if they practiced using waaaaaay fewer RPMs when at a light.
To practice and maybe change your "launch" habits, try to get "zero" slip by almost stalling; you'll be amazed at how low you can go because our engines have so much power and are geared so low in first.
Yeah, yeah..., it's impossible to have zero slippage.
My point? When I start off from a stop you can't tell that my car is a manual by the engine revving; it's absolutely minimal slippage-wise.
My bet is a huge percentage of guys could get more service life out of their clutches if they practiced using waaaaaay fewer RPMs when at a light.
To practice and maybe change your "launch" habits, try to get "zero" slip by almost stalling; you'll be amazed at how low you can go because our engines have so much power and are geared so low in first.
Aug 19, 2008 6:27:54 PM
- 69bossnine
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Re: Clutch life expectancy
Quote:
MMD said:
Your clutch should have almost "zero" slippage when going from a stop (assuming you're driving quietly and politely).
Yeah, yeah..., it's impossible to have zero slippage.
My point? When I start off from a stop you can't tell that my car is a manual by the engine revving; it's absolutely minimal slippage-wise.
My bet is a huge percentage of guys could get more service life out of their clutches if they practiced using waaaaaay fewer RPMs when at a light.
To practice and maybe change your "launch" habits, try to get "zero" slip by almost stalling; you'll be amazed at how low you can go because our engines have so much power and are geared so low in first.
Yeah, but 1st-gear requires the least amount of clamping power, therefore the wear on the clutch and pressure plate is the least with a first-gear engagement...
Not that you can't fry a clutch over time with bad technique in ANY gear, but, it's slow (long-duration) and rev-happy engagement in your upper-tier gears that will really accelerate failure.
You're right MMD, I just wanted to add that there's more to the story...
Anybody who's taken a clutch all the way to the grave, knows that it starts slipping under-power in 6th gear first, then 5th, then 4th, and so-forth... That shows you the clutch is most heavily taxed in the gears that are of greater mechanical disadvantage...
Aug 19, 2008 6:54:44 PM
- MMD
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Re: Clutch life expectancy
Quote:
Atlas997 said:
Gents, slightly OT, and I know this sounds like a basic question, but how do you "throttle blip" on downshifts. I know what it means, you can clearly hear it in cars where the drivers do so, but I just do know what foot/hand co-ordination and timing is needed to achive this.
The main reason I ask is because my downshifts have never been smooth and its something I loathe about my driving. I haven't figured out to smoothly downshift although its my understanding that throttle blip action can help.
If this question open too big a topic for discussion here then by all means direct me to links on the web the that describe how this can be achieved.
2 ways:
1 - If you do not need to brake just blip the throttle while the clutch is down and you are downshifting (try to raise RPMs about 2000RPM).
2 - If you need to brake, use the classic "heel-and-toe" technique. In a modern 911 you can simply put your right foot covering the brake and throttle pedals (you can also angle your foot). Use the left side of your right foot to break and the right side to blip the throttle when the clutch is down while downshifting. You will need to practice this enough in safe locations and make sure that you do not compromise braking.
I hope this is clear.
Aug 19, 2008 8:46:41 PM
- 69bossnine
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Re: Clutch life expectancy
"When I was young..." I used up the stock clutch in my modified '88 GT Mustang in 65K miles.... But that's what 100+ drag-strip passes, and countless stop-light battles, will do for ya...
Good riddance, the Centerforce dual-friction unit I replaced it with was the cat's pajamas... It outlasted the rest of the car...
Good riddance, the Centerforce dual-friction unit I replaced it with was the cat's pajamas... It outlasted the rest of the car...
Aug 20, 2008 9:41:00 AM
- MarekN
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Aug 20, 2008 8:24:05 PM
- Silver Bullet
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Re: Clutch life expectancy
Quote:
Atlas997 said:
Many thanks for those who clarified the throttle blip action. It indeed appear to be a case of practice makes perfect.. and i will certainly give this a try - I just hope I will not screw up the gearbox in the process
I would not worry about heel'n'toe at all. It is nearly totally irrelevant on the road and is mainly a technique that is useful on the track.
Also, you must first master throttle blips when downshifting before you can master heel'n toe downshifts (which are really just a complicated throttle blip as I'll describe below).
As you know, when you downshift and let out the clutch, you can feel the car slowing down and hear the engine RPMs increasing to accommodate the lower gear. What you should be doing, while the clutch is in, is giving a little bit of gas ("blipping the throttle": appropriately named because it is not a sustained increase on the throttle as if you were trying to hold the RPM at a certain number) so that the RPMs will increase (ideally to exactly the same RPM they would end up at after letting out the clutch as desribed above) and then let out the clutch. The trick is timing the action of letting out the clutch at the point when the RPM's are appropriately matched, preferably at the peak RPM that your throttle blip achieves or just afterwards. By doing so, you match the engine speed to the wheel speed and save your synchros from having to do so. This will extend the life of your clutch, plus its really fun to do. When accomplished well, you don't feel any rapid deceleration when the clutch is let out: its a perfectly smooth downshift because you've pre-matched the engine speed for the next gear before it was engaged. You have to learn what engine speed sounds appropriate for the car's speed in any given gear, how to achieve that RPM consistently with a given amount of throttle action, and to time the sound of the achieved engine speed with the action of releasing the clutch.
Once you have this mastered, then you can master the art of doing the throttle blip with your heel (or right side of your foot if you prefer) while your toe (or left side of your foot if you prefer) is simultaneously braking. But I wouldn't worry about that at this point (or ever really if you never plan to hit the track).
Aug 20, 2008 9:09:44 PM
- 69bossnine
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Re: Clutch life expectancy
I think we're getting a bit lost in the use of words...
Both Silver Bullet and Adias are instructing on the same methods, just using different words, possibly different techniques.
Silver Bullet's instructional was more complete, more specific.
A "blip" is just a word, that could be an arbitrary stab at your gas pedal, or just a FAST and PRACTICED manner of getting a perfect rev-match. A faster "blip" comes into play when you're using the engine as a brake, as all you need the rpm's for is to engage the gear at a matched-rev, after which you're back off of the gas pedal so that the engine can brake. How much TIME you take, i.e. whether or not you have to sustain for a bit, then off, or if you can do the whole operation in the speed of a "blip", depends on how practiced/slick you are with the operation... A practiced driver can effect a perfectly rev-matched and clutch-friendly downshift in the timespan of a "blip". But if your blip is just a stab in the dark, you may be doing more harm than good.
The sustained rev-match is more for dropping a gear in anticipation for using the lower gear for any reason that has to do with accelerating, or being at least "prepared" to accelerate... The most common scenarios that I'll do a sustained rev-match is when I'm beginning to approach slower traffic on a 2-lane road in anticipation of passing... I always have myself in the correct gear that I think I'll need well in advance of slowing... So if I can go I just roll into the throttle... But if I need to slow down I'm already in a lower gear so I can allow the engine to brake me down to the slower speed.. When I'm sustaining the throttle beyond the shift, it's because I'm sustaining speed as well. Constant speed, but lower gear. I usually drop two gears at a time, I don't fuss around with 1-gear drops, it's a waste of bushings...
But when I'm downshifting to shed speed, I'm sustaining only long enough to get the clutch back out, which is fast enough that it'll sound like a "blip", and you could call it that..
Where I disagree with Bullet is in the everyday value of being good at these techniques. I use them at all times, in the interest of increasing the lifespan of my brakes, and hence keeping my wheels cleaner for longer... Yep, it's one-half the Schumacher in me, and one-half the Felix Unger in me...
But done incorrectly, you're just robbing Peter to pay Paul..
Which is why I fixated upon doing it well, frequently, and practicing, from an early age.... I can make a clutch and a set of brake pads go A LONG WAY..
Both Silver Bullet and Adias are instructing on the same methods, just using different words, possibly different techniques.
Silver Bullet's instructional was more complete, more specific.
A "blip" is just a word, that could be an arbitrary stab at your gas pedal, or just a FAST and PRACTICED manner of getting a perfect rev-match. A faster "blip" comes into play when you're using the engine as a brake, as all you need the rpm's for is to engage the gear at a matched-rev, after which you're back off of the gas pedal so that the engine can brake. How much TIME you take, i.e. whether or not you have to sustain for a bit, then off, or if you can do the whole operation in the speed of a "blip", depends on how practiced/slick you are with the operation... A practiced driver can effect a perfectly rev-matched and clutch-friendly downshift in the timespan of a "blip". But if your blip is just a stab in the dark, you may be doing more harm than good.
The sustained rev-match is more for dropping a gear in anticipation for using the lower gear for any reason that has to do with accelerating, or being at least "prepared" to accelerate... The most common scenarios that I'll do a sustained rev-match is when I'm beginning to approach slower traffic on a 2-lane road in anticipation of passing... I always have myself in the correct gear that I think I'll need well in advance of slowing... So if I can go I just roll into the throttle... But if I need to slow down I'm already in a lower gear so I can allow the engine to brake me down to the slower speed.. When I'm sustaining the throttle beyond the shift, it's because I'm sustaining speed as well. Constant speed, but lower gear. I usually drop two gears at a time, I don't fuss around with 1-gear drops, it's a waste of bushings...
But when I'm downshifting to shed speed, I'm sustaining only long enough to get the clutch back out, which is fast enough that it'll sound like a "blip", and you could call it that..
Where I disagree with Bullet is in the everyday value of being good at these techniques. I use them at all times, in the interest of increasing the lifespan of my brakes, and hence keeping my wheels cleaner for longer... Yep, it's one-half the Schumacher in me, and one-half the Felix Unger in me...
But done incorrectly, you're just robbing Peter to pay Paul..
Which is why I fixated upon doing it well, frequently, and practicing, from an early age.... I can make a clutch and a set of brake pads go A LONG WAY..
Aug 20, 2008 11:17:42 PM
- Leawood911
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Aug 21, 2008 12:45:11 AM
- ADias
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Re: Clutch life expectancy
Quote:
69bossnine said:
I think we're getting a bit lost in the use of words...
Both Silver Bullet and Adias are instructing on the same methods, just using different words, possibly different techniques.
Silver Bullet's instructional was more complete, more specific.
A "blip" is just a word, that could be an arbitrary stab at your gas pedal, or just a FAST and PRACTICED manner of getting a perfect rev-match. A faster "blip" comes into play when you're using the engine as a brake, as all you need the rpm's for is to engage the gear at a matched-rev, after which you're back off of the gas pedal so that the engine can brake. How much TIME you take, i.e. whether or not you have to sustain for a bit, then off, or if you can do the whole operation in the speed of a "blip", depends on how practiced/slick you are with the operation... A practiced driver can effect a perfectly rev-matched and clutch-friendly downshift in the timespan of a "blip". But if your blip is just a stab in the dark, you may be doing more harm than good.
The sustained rev-match is more for dropping a gear in anticipation for using the lower gear for any reason that has to do with accelerating, or being at least "prepared" to accelerate... The most common scenarios that I'll do a sustained rev-match is when I'm beginning to approach slower traffic on a 2-lane road in anticipation of passing... I always have myself in the correct gear that I think I'll need well in advance of slowing... So if I can go I just roll into the throttle... But if I need to slow down I'm already in a lower gear so I can allow the engine to brake me down to the slower speed.. When I'm sustaining the throttle beyond the shift, it's because I'm sustaining speed as well. Constant speed, but lower gear. I usually drop two gears at a time, I don't fuss around with 1-gear drops, it's a waste of bushings...
But when I'm downshifting to shed speed, I'm sustaining only long enough to get the clutch back out, which is fast enough that it'll sound like a "blip", and you could call it that..
Where I disagree with Bullet is in the everyday value of being good at these techniques. I use them at all times, in the interest of increasing the lifespan of my brakes, and hence keeping my wheels cleaner for longer... Yep, it's one-half the Schumacher in me, and one-half the Felix Unger in me...
But done incorrectly, you're just robbing Peter to pay Paul..
Which is why I fixated upon doing it well, frequently, and practicing, from an early age.... I can make a clutch and a set of brake pads go A LONG WAY..
It's interesting that my succinct and accurate instructions led to a river of ink...
Aug 21, 2008 1:00:47 PM
- 69bossnine
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Aug 22, 2008 4:10:14 AM
- Silver Bullet
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Re: Clutch life expectancy
Quote:
69bossnine said:
Where I disagree with Bullet is in the everyday value of being good at these techniques.
To be clear, I only think that heel'n'toe downshifts are largely irrelevant in the real world. Using the throttle to match engine speed to gear speed on downshifts is very useful (and fun), as you've described, but having to brake and downshift at the same time (which is what heel'n'toe is all about) is something that's really only relevant when there is a stopwatch ticking or another car to beat where the fractions of a second required to do the downshift after braking slow you down.
Heel'n toe downshifting is often misunderstood, and over-rated as some kind of "awesome driving skill". If you've mastered the techniques that you've described in your email Boss, then heel'n'toe'ing is relatively easy to pick up. The key is learning to do the throttle blip well, and that is what beginners should focus on.
Clearly, this is a topic we're both passionate about.
Aug 22, 2008 4:12:32 AM
- Silver Bullet
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Aug 22, 2008 2:41:04 PM
- 69bossnine
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Re: Clutch life expectancy
I agree that Heel'n'toe is rather easy and over-rated when the pedal-placement is right... It's no different than straight-up-rev-matching, just with your foot bridging the brake pedal... Whoop-die-doo..
And I agree, it's rare that I'm doing it on the street. When I'm using the engine as a brake, It's typically to shed speed leisurely, like coming off an Interstate onto a long off-ramp...
I always thought that the benefit of heel-toe-ing in racing was two-fold, to get your downshift done during the course of braking (no lost time), AND to help save the brakes by virtue of engine-brake-assistance.. It's a win-win.
Rather worthless on the street though, as your brakes are already strong enough to maximize tire traction, and you're not going to torch your brakes on back-road twisties...
And I agree, it's rare that I'm doing it on the street. When I'm using the engine as a brake, It's typically to shed speed leisurely, like coming off an Interstate onto a long off-ramp...
I always thought that the benefit of heel-toe-ing in racing was two-fold, to get your downshift done during the course of braking (no lost time), AND to help save the brakes by virtue of engine-brake-assistance.. It's a win-win.
Rather worthless on the street though, as your brakes are already strong enough to maximize tire traction, and you're not going to torch your brakes on back-road twisties...
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