964 Clutch Pedal Operation Improvement
09-23-2002, 01:00 AM
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964 Clutch Pedal Operation Improvement
964 turbo clutch pedal operation improvement
Please note, the decscription below applies to the 964 Turbo, but may also be applicable to other models.
Background
From the first day of ownership of my 964 that is two months ago!, I found the clutch pedal operation very annoying. Instead of concentrating on enjoying my driving, I noticed that I was constantly aware of how the clutch was being depressed/released etc. In my many years of driving manual vehicles, this experience was never encountered. So I decided to investigate further, and the following outlines my findings and results which occured last weekend.
Problem 1. Non linear clutch pedal pressure
The single most annoying aspect [in my oppinion] is that the clutch pedal presure is not linear. I don’t know if anyone has noticed that when depressing the clutch pedal, foot pressure increases steadily for the first initial 75% of travel, then suddenly the remaining 25% of pedal travel becomes very easy.
The engineers at Porsche are smart little buggers by designing a system of levers and springs to allow a relative lower foot pressure requirement while holding the clutch released, when for example at a traffic lights. The problem is when you begin to release foot presure on the clutch pedal, the pedal pressure increases markedly and quite suddenly. This action I found prevented consistent and smooth clutch engagement.
Problem 2. Excessive clutch pedal movement
The next issue was the amount of pedal movement, which seemed excessive when compared to when the clutch release and full engagement points are reached. In simple terms, I looked at the total pedal movement range and then compared to the pedal position that the clutch was either fully engaged or dissengage. What I noticed was that the clutch had fully dissengaged approximatelly 75% before the stop point, the remaining movement did nothing at all, except open the clutch springs further.
Similarly when releasing the pedal, full clutch engagement occured during the initial 30-35% of pedal movement, with the remaining 65-70% or so of little use, resulting in roughly 60% of unecessary clutch pedal movement.
Please allow me repeat myself by stating the above percentage distances are provided as an example to emphasise the large amount of pedal movement as compared to what is really necessary.
Problem 3. Clutch pedal not aligned
Clutch pedal too far forward and not lining up with the brake pedal. This alone was not a major issue in itself, except to cause some difficulty when having to lift my left foot off the rest to get to and press the clutch pedal.
Success
Well the good news is I have improved or fixed all the above issues. My clutch pedal is now smooth with linear foot pressure, and interestingly enough not much more than before. The engagement/disengagement points are precise and consistent thus resulting in smooth clutch operation. The total pedal movement has been reduce, allowing much faster gear changes, and as a bonus allows movement between the footrest and the clutch pedal a little easier.
Oh I nearly forgot, firstly I also managed to incline the accelerator pedal to the right towards the wheel arch, thus providing more clearance between the accelerator and the brake pedal. Secondly it costs absolutely nothing to perform this minor modification, except about 2 hours work around and under the pedals area.
So if anyone out there would like detailed instructions on how to do this, just let me know.
Cheers for now
Peterv
964 Turbo 3.6
Please note, the decscription below applies to the 964 Turbo, but may also be applicable to other models.
Background
From the first day of ownership of my 964 that is two months ago!, I found the clutch pedal operation very annoying. Instead of concentrating on enjoying my driving, I noticed that I was constantly aware of how the clutch was being depressed/released etc. In my many years of driving manual vehicles, this experience was never encountered. So I decided to investigate further, and the following outlines my findings and results which occured last weekend.
Problem 1. Non linear clutch pedal pressure
The single most annoying aspect [in my oppinion] is that the clutch pedal presure is not linear. I don’t know if anyone has noticed that when depressing the clutch pedal, foot pressure increases steadily for the first initial 75% of travel, then suddenly the remaining 25% of pedal travel becomes very easy.
The engineers at Porsche are smart little buggers by designing a system of levers and springs to allow a relative lower foot pressure requirement while holding the clutch released, when for example at a traffic lights. The problem is when you begin to release foot presure on the clutch pedal, the pedal pressure increases markedly and quite suddenly. This action I found prevented consistent and smooth clutch engagement.
Problem 2. Excessive clutch pedal movement
The next issue was the amount of pedal movement, which seemed excessive when compared to when the clutch release and full engagement points are reached. In simple terms, I looked at the total pedal movement range and then compared to the pedal position that the clutch was either fully engaged or dissengage. What I noticed was that the clutch had fully dissengaged approximatelly 75% before the stop point, the remaining movement did nothing at all, except open the clutch springs further.
Similarly when releasing the pedal, full clutch engagement occured during the initial 30-35% of pedal movement, with the remaining 65-70% or so of little use, resulting in roughly 60% of unecessary clutch pedal movement.
Please allow me repeat myself by stating the above percentage distances are provided as an example to emphasise the large amount of pedal movement as compared to what is really necessary.
Problem 3. Clutch pedal not aligned
Clutch pedal too far forward and not lining up with the brake pedal. This alone was not a major issue in itself, except to cause some difficulty when having to lift my left foot off the rest to get to and press the clutch pedal.
Success
Well the good news is I have improved or fixed all the above issues. My clutch pedal is now smooth with linear foot pressure, and interestingly enough not much more than before. The engagement/disengagement points are precise and consistent thus resulting in smooth clutch operation. The total pedal movement has been reduce, allowing much faster gear changes, and as a bonus allows movement between the footrest and the clutch pedal a little easier.
Oh I nearly forgot, firstly I also managed to incline the accelerator pedal to the right towards the wheel arch, thus providing more clearance between the accelerator and the brake pedal. Secondly it costs absolutely nothing to perform this minor modification, except about 2 hours work around and under the pedals area.
So if anyone out there would like detailed instructions on how to do this, just let me know.
Cheers for now
Peterv
964 Turbo 3.6
09-26-2002, 09:06 AM
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Join Date: Jan 2002
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YES...I thought I was the only one who hated my clutch operation! <img src="graemlins/beerchug.gif" border="0" alt="[cheers]" /> let me know how to fix that bugger!!
Thanks, Kevin
Thanks, Kevin
09-30-2010, 08:32 PM
#5
Rennlist Member
The clutch actuation is a master & slave configuration. Usually the slave cylinder goes bad, which results in a clutch pedal that doesn't fully return. The other difficulty is a worn pedal cluster (it sits down in a lot of contamination) which may require rebuilding.
Other than that, there is no way to adjust the engagement point of the clutch. It is what it is.
Other than that, there is no way to adjust the engagement point of the clutch. It is what it is.
