Planet 9

Thanks again Nexus-6, I agree you need to adjust a bit from a dead stop but the end result is all good.

J Cay asked if 0-60 time might be better and I would say yes what do you think ?

Nexus-6

BTW I made a plastic cap that is .430 long with a .417 bore and it will slip over the pin and slightly press on to the switch body below and holds the switch in the depressed position and then there is no needed to tape or even take the switch out and with this cap you can do this mod in 20 seconds or less and reverse it the the same amount of time. The cap fits in a position so the part of clutch pedal that makes contact with the switch pin does not touch the cap so repeated clutch pedal operation will not effect the cap and it's funtion.

To show thanks to you for your post on this mod you may if you so choose send me a PM for one free cap.

Elmo,

That sounds like a fantastic and elegant solution! I'd be tickled to take one of those caps - PM on the way.

Two points:

1. With the mod, cruise still deactivates if you dip the clutch

2. I noticed that there is a red plug which fits into the back of the switch.
Instead of capping of taping the switch, if we disconnected the plug would that mean the car would think the clutch was always up or always floored?

So...is this the REAL reason why the car is so stall happy? I have always felt that it was odd that it took so many revs to pull away from a stop.

Without exception, parking attendants stall the car.

Read this:

http://www.zeckhausen.com/CDV.htm

How is the switch under the clutch involved with this? (I know this is a BMW...but how is ours different?)

__________________

2007 Speed Yellow Cayman GT 2.7 (retired)
2008 Guards Red Cayman GT 3.4
"Carpe Cayman"

Excellent news on the cruise feature still working. Hadn't gotten around to trying that.

I'm guessing that unplugging the switch, versus tricking it via tape (or caps) will throw a code for certain. With the circuit completed, even if it's not functioning correctly, it seems not to care. I'm guessing, though of course not 100% certain, that unplugging the switch = incomplete circuit = CEL or code.

Having owned 7 BMWs in the past several years, I've become rather familiar with the CDV method they employ (note that familiar and fond are very different things!). Defeating or removing it in each one meant a world of difference. In fact, with more than one it meant the difference between being able to drive without thinking about it (as all of us old fashioned manual lovers like to do) or constantly trying to avoid stalling the car or jerking shifts under normal driving conditions...devoting cycles to a process we would much rather take for granted.

Simply put, the BMW method (Clutch Delay Valve) is the mechanical way of doing what Porsche, Mazda and others are doing in software. The CDV is a narrow portion of the clutch fluid line, just before the slave. And by narrow, I mean it's a pin hole - what happens is that fluid is passed through here more slowly than it would in a proper size tube. This means that your input (clutch has been operated - all done!) isn't 1:1 with what's actually taking place. A fraction or two later, the clutch, now delayed by the slowly returning fluid in this narrow portion, engages the flywheel completely, but not at the moment you complete your portion of the equation.

I will say that a sloppy driver will find a CDV-less BMW very tricky to drive smoothly, especially if they had previously become accustomed to the "help" the CDV was providing. Smooth and experienced drivers will appreciate that the clutch pedal will actually directly modulate where the clutch disc is at in the operation. Most folks that defeat the CDV so they can actually shift quickly at redline without the slight (but measurable) delay the valve creates. In other words, folks often do it so they can chirp 2nd gear. Others (like myself) do it simply because our brains are wired from past years of driving to expect that the pedal on the left there directly modulates the clutch, and thus the smoothness of our uptakes post shift. To have it modified slightly puts our brains off just a bit. If you're the sort of person who loathes understeer, the CDV is the sort of thing that drives you bonkers. You want immediate, direct and expected results from your actions. Anything that interferes with or lags that, well...it bugs us is some deep ways.

I have no idea if Porsche involves more than just a software version of the clutch delay by employing that switch (they may use it for other things...as a feedback loop, it's a pretty solid example...to the switch, the clutch is either out, or in and this data could be used for other things I imagine).

I just tried this mod and I can tell you the difference is night and day....not dusk and dawn but night and day...especially in first...my foot and clutch now work in unison...before I thought - "now I know I haven't driven a manual in quite some time and that I was rusty", taping up this button I now think...hmmm my skills weren't so bad after all. I don't know whether to leave it or try to get used to Porsche's high revs to move out of first. Really what's the real harm...and why is this there in the first place.

Man I'm getting tempted to try this out... like saucerman, I'd appreciate a discourse on what any harm would be.

The sluggish clutch engagements and the brraapp, especially accentuated with the AWE exhaust when in parking garages, really makes me want to do this.

__________________
- Suneet

So true.

I hate variable power steering for the same reason.

Hey,Nexus-6

Got your PM and cap is on it's way.

Now I know what that sound is. The dreaded "brraapp".

I am giving this one a try.

__________________

2007 Speed Yellow Cayman GT 2.7 (retired)
2008 Guards Red Cayman GT 3.4
"Carpe Cayman"

In my opinion, the reason these measures even exists is to lengthen the life expectancy of the the clutch and drivetrain in general. If you can eek out another 15K miles before things need replacing (given that the clutch is a non-warranty item, but transmissions are covered and are quite pricey), well then you pad the bottom line a bit more.

In other words, I'm guessing that clutch delay devices in general are, foremost, pushed hard for by bean counters. The marketing is "smoother shifts!" but the reality is "less wear!" which means less $$ spent covering "blowed up" transmissions in the real world. And honestly, for most drivers it's not that noticeable so it makes the case pretty simple for car makers in general. Case in point = my wife. The only difference she detects is that the car is touchier from a stoplight. But she may drive the car, at most, 2/10s at her friskiest. For her, and for many, the difference is almost imperceptible. For me though, it was night and day...and got rid of the flatulence!

It's my understanding that you can more or less beat the living !@#!@ out of a BMW with CDV (high rev clutch dumps, power shifting, etc) and within reason, the CDV does a good enough job at protecting the clutch, flywheel, trans from shock that you can't really do much harm. Without it, that safety buffer isn't there to absorb the shock if you're brutal with the car.

My point in all of the above is that I don't believe there will be any harm whatsoever in disconnecting the switch (or defeating it) short to medium term for folks who don't abuse their cars. Long term (and by that I mean 75~100K miles) I can imagine more clutch and flywheel wear without the switch operating, but for me, that's of no concern as I doubt that my 987 will ever see more than 40K during my ownership. If it does throw a CEL or store a code at some point, that could be a nuisance to deal with, but it's a simple task to erase it - and, touch wood, she hasn't thrown any codes in 200 miles as of this evening. If anyone is concerned about warranty work, you can always remove the tape (or cap as Elmo has devised) and you'll be back to normal in less time than it took me to type this sentence. Of course it should be stated that I might be talking directly out my rear end here as I'm not an engineer for Porsche, but I'm relatively confident that it's the same line of thinking as BMW and others (extend the life expectancy of certain expensive to replace/fix parts).

The comparison to variable rate steering is spot on - I had to fight tooth and nail with my sales guy a few years ago as to why I didn't want it on my 335i, and felt oddly out of place defending my preference for direct and precise interactions, sans assistance. He finally let up when I used the (lame) statement "It's the ultimate driving machine, right? When did they begin selling the ultimate parking machines?"

Would it be possible for you to post a picture or a how-to for the group?

__________________
When the going gets weird, the weird turn pro.

Hello, Nexus-6. You rule, man.

The CDV mod was the first functional change I had done to my ordered E90, done in my first week of owning it. I still have the E90 and I can't imagine driving it with the CDV. No regrets!

Now in my third 987 car, I am anxious to feel the equivalent improvement in it. I will consider the implications of doing this mod (warranty, really) before doing it. But I foresee trying it soon.

Finally, I understand why I can almost never do the little K turn (required to park in my carport) without goosing my neighbors. The Tubi exhaust accentuates this, of course, so I thought it was at least partly to blame. The poor, innocent Tubi, maligned and misunderstood.

Thank you!


Snaxster

__________________

2008 Boxster Black/Black/Sand Beige, 6-speed, PASM, 18" Boxster S wheels, Preferred Package Plus,
Sport Steering Wheel, Automatic Climate Control, Windstop, Hardtop, Porsche rubber floor mats,
deleted model designation, clear side markers, 3M clear bra, set of winter tires and wheels.

Thanks- did it. I always wondered why no amount of throttle could affect the bogging situation. I always figured I was slipping the clutch way too much and all that time it was awol!

__________________
996 GT3 lower control arms at all corners
997 GT3 front sway bar
Quaife TBD
DMC harness bar/G-force harness
Hawk HP Plus pads

Maybe Nexus-6 will post a picture I sent him a cap, but if you have ever replaced the cap on the end of a BIC pen or magic marker this mod requires the same time and skill level if you have a cap or follow Nexus-6 method of removing the switch and using tape but as he says do not try to replace switch as it will damage tape that is holding the pin in the depressed position.

I took some pictures of my switch for those interested:

This this looking straight up from the footwell directly above the clutch pedal (i.e. the pedal is directly below the bottom of this image.) The switch is roughly terracotta in color, which matches my interior nicely!


To remove it, simply turn the whole switch counter clockwise, and back it out through the bracket its mounted on (back towards the driver's seat). It comes out with very little effort.

This is what the removed switch looks like:


There is a connector on the back that attaches to the switch with two small plastic clips. You can spread the clips with your fingernails and then simply pull the connector off the switch.

The connector removed looks like this:


Since I don't care for sticky tape much, I opted for the electrical bypass. A small piece of wire with the ends stripped, stuffed into the two sockets on the connector will do the trick.

Looks like this:


When the clutch is disengaged (your foot off the pedal), the switch is closed (completely closed; I measured it). When engaged, the switch is completely open. The wire you've shoved in the connector will keep the circuit closed all the time. There won't be an CELs with the switch removed.

Just tuck the jumpered connector up under the dash and either take the switch out of the car completely or put it back in the bracket (with the connector disconnected and jumpered).

-- Sam

Suneet....

go ahead and try this....I just used a piece of duct tape at first...didn't even bother with taking the switch out of place...took me all of 30 seconds and was out the the driveway...as soon as I put her in first I noticed a difference right away...I was pretty much in awe that a simple mod such as this dramatically makes a difference.

Looking in one of the parts catalog the switch may be represented by figure 16 in the Section on Hand Controls and Pedals the PN is 997 613 109 00.

Two comments:
First, the picture of switch does not look like switch in photo (just an observation).

Second, the application is for model I480 (I480 = 6 speed) does anyone with a 5 speed have this same switch or is it a 6 speed only application? Being a 997 PN seems to imply that 911 model also uses this switch.

Question:

Since this is an electric switch, how does it delay clutch? or effect engine RPM?

In BMW it is a hydraulic restriction (metering orifice) thus limiting release rate of slave cylinder - therfore clutch engagement rate.