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Old 08-31-2006, 09:22 AM   #1
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Question Clutch

hello, I just purchased my first ever Porsche, a 2001 Speed Yellow Boxster S with only 7600 miles, 18" Porsche 10-spoke wheels, Pirelli P Zero Asimmetricos ..what a great car!! the handling is so tight, the smooth accelleration, ...great car!... anyway, you guys already know these are great cars, thats why you're here. ...my question: how gentle do I need to be with the clutch? , in order to transition smoothly thru the gears, I have to let the clutch out somewhat slowly, not REAL slowly, but I can't just pop my foot off between 1 and second for example, is this bad on the clutch? if I release the clutch very quickly the shift is jerky and seems harsh on the car, are my RPMs wrong or is it OK letting the clutch out slowly?
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Old 08-31-2006, 01:42 PM   #2
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Wise or not, I've let alot of people drive my 987 and 987S over the last year plus (always with me in it), and it's pretty shocking some of the atrocious shifting habits one sees. Newt, I've never seen you drive so it would be inappropriate for me to categorize you as a bad driver, but from reading your post, it sounds like you operate under a misconception that would rank as the number one observed bad habit that I've seen. A habit whose origins only occurred to me after watching others disintegrate my clutch.

You're attempting to time/control the initial clutch release with your left foot, which is a slippery slope only leading to frustration. You should coordinate the clutch extension and release with the extension and drawing back of your left knee. Although there are movement in the left foot they are reactive not proactive and their primary function on release is to keep resistance on the clutch so it doesn’t pop back in an uncontrolled manner, as the left knee is obviously not in direct contact with the clutch pedal.

Reasons why this work:

Because the knee has a very limited range in motion, and drawing it back is a move that can be done consistently over and again. Your ankle and feet have roughly the same motion as your hand. While this enables feet to work well enough for delicate tasks like balancing and dipping toes in swimming pools, their wide range of motion and the weakness of small muscle groups makes them pretty useless as clutch controls. Try this experiment: Extend and retract your left leg while you’re sitting at your desk, leading the actions with the foot. The motion is a tentative forward and back. Now extend and retract your leg using your knee to control the movement. You’ll note that your foot confidently extends and reflexively pops up… and then retracts heel first, down and back. This natural motion exactly matches the operation of the clutch pedal.

Because the pedals are set up for this. It’s obvious from comparing a clutch and a gas pedal that the two are meant to be controlled in different ways, but most drivers try to use a similar micromanagement technique on both. I’m sure that Delphi would create a clutch pedal that could be controlled like a gas pedal if that made any sense.


Reasons why it won’t work for you:

Because you have no faith. If you try to bring the knee back, thinking about what the foot is doing you’ll still be prone to riding the clutch. Assuming that you’re leading the shift with gas first (which of course is mandatory), the clutch release with the knee is smooth and seamless. This requires a leap of faith, and tentatively manipulating your foot while simultaneously controlling with your knee is a disturbing lack of faith. The foot just supplies resistance. Not that it’s wooden, it just buffers and counterbalances the interacting forces from your leg and pedal resistance.

Because you’re trying to be Mario Andretti and do it too fast. There’s still a timing factor, particularly in that the Porsche requires more loud pedal in most circumstances than other cars, and the action will naturally become faster as you get more comfortable.

Your body is not positioned correctly. This works well in the Porsche if you are seated appropriately close to the wheel, with the hips in a semi-reclined position. Sit close enough so where the push-in and release of the clutch controlled by the knee feels reflexive, which is probably a good deal closer than you’re seated currently. In this position, the shifter will also feel at-hand. If you’re seated too high and upright, your shins get in your own way.

If your steering wheel is adjustable for rake, I’d also urge you not to have the wheel set too high. If you look at race car setups, the wheel is set low, which is conducive to coordinating the body movements required to drive well. It’s difficult to perform athletic movements when your torso is overly reclined, which a high steering wheel position encourages. Think “formula one car” not “rolling in the hood foshizzle bizzle”.

What this takes care

Labored starts out of first
Tentative acceleration
Slow shifts
Fatigued clutch foot
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Last edited by SD987; 08-31-2006 at 01:45 PM.
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Old 09-01-2006, 06:11 AM   #3
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thanks SD987, ....the clutch release with the knee movement as you described is the way I'm doing it so I feel good about that, however I don't know what you mean by:

"There’s still a timing factor, particularly in that the Porsche requires more loud pedal in most circumstances than other cars, and the action will naturally become faster as you get more comfortable."

What is "loud pedal" , I suspect I'm not "leading the shift with the gas" properly...If you don't mind explaining I would appreciate.....

PS: I want to do some PCA drivers ed soon.....
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Old 09-04-2006, 10:42 AM   #4
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Clutch management

Thanks SD987 And Newt for bringing this control problem to the forum. I recently changed my 2000 986 for a 2004MY 986 S and the first thing I noticed was my tendency towards bad gearchanging and the lurching that goes with it. SD987 has made some good suggestions and I'll be looking to adjust my technique. In the non S, there was a sort of back pressure at the end of the clutch which finalised the engagement and gave a good transition. It doesn't seem to be present on the "S".
Another part of the problem for me in the UK is that our roads are very congested and when driving in town, there is hardly room for accelleration so by giving the "loud pedal" a quick burst, I can be right on top of the pensioner in front of me. UK drivers are being encouraged to stay within the 30mph limit and that means that many drivers don't go above 25mph. Its very frustrating.
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