clutch mods

[The Radium King]

don't think this has been discussed here before (i'd heard about the switch mod before but didn't think it applied to the 9x6 series):

Anyone Else Mod Their Clutch Delay Switch? - Rennlist Discussion Forums

give it a read. follow the links to the helper spring mod and the switch mod. what say ye?

[Dlirium]

If there is a mod to be done, I'm doing it! Now, let me go read the link :-)

[Dlirium]

well, after reading, this post probably talked me out of trying it:

=======

It's not really a "Clutch Delay Switch". A "Clutch Delay" would slow the release of the clutch, and it's usually a mechanical device like a manifold with a fixed orifice to slow the flow of hyrdaulic fluid from the cluch slave cylinder. BMWs (expect M models) use a clutch delay to make the cars easier to drive / harder to stall.

The switch you're talking about does one thing for several reason, one of them overlaping the benefits of a clutch delay. It retards the timing when you press the clutch, and for a short time after the clutch has been released.
1. Retarding the timing reduces shift jerk which makes shifts smoother, but more importantly protects the Dual Mass Flywheel from damage.

2. During take offs, retarding the timing reduces the chances of knock/ping on clutch release. This makes it much easier to launch without stalling (the overlap I was taking about).

3. By knowing when the clutch is being depressed, the DME can widen the range of acceptability in it's misfire detection module.
Here's a quote directly from the Porsche Tech archives: "The program that evaluates misfire is complex. it has to be able to distinguish between deceleration caused by rough roads, potholes, shifting, and other non misfire causes, and deceleration caused by misfire."
4. By knowing then the car is shifted (watching the clutch), the Torque Control can reduce engine braking during high torque downshifts.
Here's another quote from the archives: "On deceleration with unacceptably high engine braking when downshifting, engine drag torque control (MSR) prevents the drive wheels from locking on a slippery road by slightly opening the throttle valve."

So by removing that switch, you may in fact feel some added sharpness to throttle response when shifting. Because now you have a sharper timing curve. But you will be castrating all 4 of the benefits mentioned above. To summarize:
1. You may experience premature failure of your DMF

2. You may find yourself stalling your car more frequently, and you may find that your car has less power than before, because when it preignites - the DME is going to pull the timing back and keep it back for a while.

3. You may experience a Check Engine Light, and investigation may reveal random misfire codes.

4. You may notice locking of the rear wheels after high RPM downshifts. This is most likely to be noticed on slippery surfaces like rain or snow, and it is likely to cause oversteer.

[The Radium King]

but there's also this ...

Improved Clutch Action Dramatically - Rennlist Discussion Forums

[woodsman]

Originally Posted by The Radium King

but there's also this ...

Improved Clutch Action Dramatically - Rennlist Discussion Forums

Thanks for that Radium King. Now I know why I occasionally stalled the Boxster. That spring prevents us from feeling the over-center point as well as the point of engagement. Wish I read that YEARS ago. And, it's free! The other seems overthought and unnecessary but I wouldn't bother with myself.

[jaykay]

Well I am definately going to give this a try come the thaw...

I haven definaitely noticed some clutch out weirdness on up shifts where the bite point seems to have inexplicably changed .....and all of a sudden you are slipping or grabbing too much

If we can go by the observations in the thread, perhaps this spring and dash pot canister starts to get worn giving more friction or damping resistance after a time. This would certainly disrupt clutch out feel and actuation

[JayG]

Originally Posted by jaykay

Well I am definately going to give this a try come the thaw...

I haven definaitely noticed some clutch out weirdness on up shifts where the bite point seems to have inexplicably changed .....and all of a sudden you are slipping or grabbing too much

If we can go by the observations in the thread, perhaps this spring and dash pot canister starts to get worn giving more friction or damping resistance after a time. This would certainly disrupt clutch out feel and actuation

more likely the spring has broken, I dont think it is a wear item. It either is broken or not
If it is harder to press in the clutch pedal, then spring is broken
'You can either replace the entire assembly for $75-100 or replace the spring by getting one from a junkyard orlook at this thread http://rennlist.com/forums/996-forum/343297-improved-clutch-action-dramatically.html
and it will tell you where you can locate a similar one.

Mine broke and I got one from Woody (itsnotanova) for IIRC, $15 shipped
Its an easy DIY

[jaykay]

Yes later read through the whole thing.....might be nice to try a lighter spring in there

[Redboxs]

Is it normal for the clutch to 'stick' slightly under heavy shifts?

By heavy.. I mean "spirited"

[jimk04]

I tried the mod a while ago. It does make down shift blips nicer,...ie more responsive, but it makes pulling away from stationary smoothly trickier, and therefore less kind to the clutch.

It was mentioned it would be good to put it through a switch. So you could turn it on only when wanted.

[CraigM]

Did this tonight, mixed feelings. I'll have to drive it for another day or two, but right now my plan is to put a weaker spring in. I don't like where it rests, and the pedal now squeaks terribly. The feel is improved...need more time with it...

Either way, if you want to do it, here is the easiest way:
1. Remove the vent tubing in the way - just pull one side and then the other.
2. The cruise control switch is right in the way - twist 90 degrees and pull it out of the bracket.
3. Stick a nail in the hole at the back of the unit, with the head on top or it will just fall out.
4. Pry the pin with a screwdriver - pops right out, see photo below. The gold pin is part of the spring assembly that will come out - it is held in by the pressure of the spring alone.
5. Wiggle the whole thing out.

[JayG]

I tried the lighter spring and prefer the factory one

[woodsman]

Originally Posted by Redboxs

Is it normal for the clutch to 'stick' slightly under heavy shifts?

By heavy.. I mean "spirited"

no...define 'stick'

[Kenny Boxster]

I would not recommend removing the spring completely. It will not allow the pedal to engage a plunger switch correctly, and will throw an error code in durametric after driving a couple of days. Noticed rough shifting, and odd sluggishness, decided to put in a lighter spring from home depot and problem solved. Lighter spring rate, and plunger is depressed upon using clutch pedal.

[JayG]

The home depot spring has a very very low spring rate and barely does anything

[CraigM]

Been running no-spring for a couple days now, not worth it. Same as Kenny said. My McMaster Carr spring (recommended in the Rennlist thread) should get here tomorrow, hopefully it's a good middle ground.

[Kenny Boxster]

Originally Posted by CraigM

Been running no-spring for a couple days now, not worth it. Same as Kenny said. My McMaster Carr spring (recommended in the Rennlist thread) should get here tomorrow, hopefully it's a good middle ground.

+1. Was the bee's knees with no spring, but car computer was confused and had strange rpm fluctuations and loss of power while driving. A weaker spring is a good compromise.

[Meir]

Originally Posted by CraigM

Been running no-spring for a couple days now, not worth it. Same as Kenny said. My McMaster Carr spring (recommended in the Rennlist thread) should get here tomorrow, hopefully it's a good middle ground.

Hi Craig.
mind sharing a link to the spring you ordered?
thanks.

[CraigM]

The link doesn't really work - it's just a massive catalog page, it highlights your choice, but the "link" doesn't find the product.

So, McMaster.com, search for 9657k142. You have to buy at least six, it was 19.76 after shipping. OR.....

You can PM me and I can ship you one, $2 plus actual shipping, pay via paypal. I'll have 4 to get rid of, gonna keep 1 as a backup.

Mine should be here tonight, and I should have some driving impressions by tomorrow night.

[jimk04]

Craig would you send me one to the UK.?