# Clutch Delay Valve modified



## salvo (Feb 28, 2004)

BrettInLJ said:


> I just got mine removed today. This guy has done them before and has been working on BMW's for 25 years (Bob @ All German Auto in Escondido, CA) and the shop has a great rep. according to other posts.QUOTE]
> 
> How much did he charge you?
> Thanks


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## DZeckhausen (Mar 11, 2003)

richard said:


> I know I'm asking to get flamed here, but I really don't see what the big deal with the BMW clutch is. Every stick I've driven takes some getting used to. They all have different engagement points and require different throttle use. I find it interesting that all the magazine reviews of the BMW line always rave about the clutch and gearbox, yet on many message boards people rip them. Granted I'm not always silky smooth with my shifts, but I wasn't on my Honda either. I blame me.


This post is like traveling back in time three years to the E39 boards when the CDV mod was first discovered. There were a bunch of posts from people who were convinced they actually liked the effect of the CDV. They attributed all sorts of characteristics to the CDV which, in fact, had nothing to do with it. It wasn't until they actually tried an E39 with the CDV removed that they became converts. Now, if you ask over on one of those forums, you won't hear ANY doubts or negative comments about the modification. It's a no brainer.

It's never a good idea to arbitrarily add delay into a control system. Imagine if your computer mouse had a 1/2 second lag for any inputs that moved it to the right, but no lag in the other three directions. If you were born and raised on such a mouse, you might be suspicious if someone proposed a zero-delay mouse. After all, you are used to the behavior and it doesn't seem to hurt anything. But after switching, you would quickly realize how much the old mouse was hurting your mousing precision. As for the other folks who were born and raised on zero-delay mouses, you can just imagine how frustrated they would be when they first bought one of these mice with the 1/2 second delay to the right. Since the mouse was part of an entirely new computer system with new software, they might not even realize it was the mouse at fault, but the system simply feels awkward. Suddenly, someone slaps a normal mouse on their computer and everything is right again!


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## SAZMan (Mar 6, 2004)

*Now I'm confused*

I've been reading a bunch of these threads on the CDV and I can't keep things straight. I've read that some E46 cars have them but some don't; I've also heard that they ALL have it. I've read that the 330Ci does NOT have it, but the 330i DOES (if true, I can't come up with a good rational for that one). Any comments?

I've heard that it makes no difference, that it makes a mild difference and that it makes a HUGE difference. The opinion seems to vary with the type of driving that is done. I'm very much a beginner manual driver, and I plan to do mostly routine driving with some occasional fun maneuvering/acceleration (I haven't gotten my car from the PC yet). Would I likely ever notice the difference, especially in my learning phase? Would removing it as a beginner place my driveline at risk, or is the damage it supposedly prevents one of intent rather than accident? Help anyone?

I've also heard some people express concern for warranty issues. Has anyone who installed the modified CDV actually have a claim denied because of the switch? If the presence of a CDV is so inconsistent, wouldn't it make more sense to take it out and act as one was never there than to install a modified one that can be discovered and scapegoated?

Just a few things I was wondering


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## FenPhen (Jan 13, 2004)

DZeckhausen said:


> Now, if you ask over on one of those forums, you won't hear ANY doubts or negative comments about the modification. It's a no brainer.


I've searched and read before for reasons why not to get it removed, but I just want to make sure definitively.

The CDV is designed to prevent quick engagement of the clutch, correct? This is to buffer the drivetrain from someone that dumps the clutch on hard launches, right?

(Like the guy that asked why the 3 doesn't give a "satisfying jerk" when he launches...  )


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## whk (Mar 14, 2003)

Just a "me too" sort of post. I bought two CDV's from Circle BMW for about $20 delivered, and I traded them with Zeckhausen for 1 modified CDV. The installation was surprisingly easy. Once you are under the car everything is easy to reach. I lost about a teaspoon of brake fluid, so there wasn't even much of a mess. I couldn't find a local dealer selling ATE or Motul brake fluid, so I spent $5 for 12 oz of official BMW brake fluid.

I don't think I got much air in the lines - the clutch pedal never got soft, and after a bit of bleeding and a lot of clutch pumping, just to be sure, the clutch felt as good as ever.

I noticed the difference in the feel of the clutch when driving right away. It is hard to quantify, but before making the swap, my clutch always felt like it engaged in two steps, that is, when it was about half-way up the pressure on my foot decreased just a bit, and it felt like it was slipping its way into full engagement. It feels better now.


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## hantavirus (Feb 17, 2002)

*my 330Ci didnt have one*



DZeckhausen said:


> On the other hand, it also says the M3 does NOT have one, yet we are finding them on the occasional M3. In that case, since BMW's own documentation says it is not there, we just yank it out and don't install anything in its place.
> 
> The only way to know for sure is to crawl under your car and check. If you're not comfortable doing this, there are plenty of BMW enthusiasts in the DC, VA, MD area who are able and willing. Just jump onto the E39 board and ask.


FYI, my 2002 330Ci did not have a CDV. It was a Euro Delivery car, but I believe that should make no difference whatsoever, since its in all other ways a US-spec car. :dunno:


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## BahnBaum (Feb 25, 2004)

hantavirus said:


> FYI, my 2002 330Ci did not have a CDV. It was a Euro Delivery car, but I believe that should make no difference whatsoever, since its in all other ways a US-spec car. :dunno:


My '04 M3 has a CDV valve. Dr. Zeckhausen is removing it on Friday.

Alex


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## Josh (PA) (Jan 21, 2002)

Dave,


Was browsing your website, a lot of great information. Question: I noted the 328i wasn't listed under e46 models covered. Have you found a CDV on 328i (particularly '00 models) and is it the same procedure?

Thanks,
Josh


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## 330soon2b (May 30, 2004)

what is the point of the cdv? does it make it easier for the regular driver to use the car, is it for performance? do you think the 0 to 60 times quoted by bmw are sans cdv? dave, looks like you are located in maplewood, nj, right around the corner from me. if i wanted to have this modified cdv installed, can you do it or recommend a mechanic? i don't have the tools to complete this type of work.


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## DZeckhausen (Mar 11, 2003)

Josh (PA) said:


> Was browsing your website, a lot of great information. Question: I noted the 328i wasn't listed under e46 models covered. Have you found a CDV on 328i (particularly '00 models) and is it the same procedure?


BMW parts CD says the 328i does NOT have a CDV. So far, I haven't seen a 328i that did. The only car that BMW documentation consistantly shows does not have a CDV and, in fact, DOES have one, is the E46 M3.


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## DZeckhausen (Mar 11, 2003)

330soon2b said:


> what is the point of the cdv? does it make it easier for the regular driver to use the car, is it for performance? do you think the 0 to 60 times quoted by bmw are sans cdv? dave, looks like you are located in maplewood, nj, right around the corner from me. if i wanted to have this modified cdv installed, can you do it or recommend a mechanic? i don't have the tools to complete this type of work.


The answer to all your CDV questions can be found here: http://www.zeckhausen.com/CDV.htm


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## BloodRedHog (Mar 9, 2004)

Dave Z sent me my modified CDV and I got in 2-3 days. If you are that close to him, go by and have him remove it - he'll bleed the clutch as well.

The easiest answer to your question would be to drive one with and without a CDV - the difference is immediate.



330soon2b said:


> what is the point of the cdv? does it make it easier for the regular driver to use the car, is it for performance? do you think the 0 to 60 times quoted by bmw are sans cdv? dave, looks like you are located in maplewood, nj, right around the corner from me. if i wanted to have this modified cdv installed, can you do it or recommend a mechanic? i don't have the tools to complete this type of work.


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## dynosor (Jul 15, 2003)

*What about throttle lag?*

CDV removal may help one part of the equation. I find throttle lag even more infuriating. Open the throttle quickly but progressively and it ignores your starting ramp only to snap open and jerk like you don't know what your'e doing.


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## phelix (Aug 3, 2004)

> Was browsing your website, a lot of great information. Question: I noted the 328i wasn't listed under e46 models covered. Have you found a CDV on 328i (particularly '00 models) and is it the same procedure?


For what it's worth my UK-spec 99 328i doesn't seem to have a CDV.


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## DZeckhausen (Mar 11, 2003)

phelix said:


> For what it's worth my UK-spec 99 328i doesn't seem to have a CDV.


Your observations are consistant with what I've seen on the American models. Unlike some other differences between USA and BMW models sold across the pond, the CDV doesn't seem to be designed to compensate for "dumb American" drivers.

Examples of such "protective" devices include the European vs American dash of the E39 and the use of knee airbags in the American version of the E65 7-Series. Both are designed to protect unbelted drivers and front seat passengers from submarining under the dash in a frontal impact. Despite trememndous progress in domestic seat belt use, the Europeans still view Americans as morons who don't know how to drive and don't buckle up while driving badly.


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## phelix (Aug 3, 2004)

> Examples of such "protective" devices include the European vs American dash of the E39 and the use of knee airbags in the American version of the E65 7-Series. Both are designed to protect unbelted drivers and front seat passengers from submarining under the dash in a frontal impact. Despite trememndous progress in domestic seat belt use, the Europeans still view Americans as morons who don't know how to drive and don't buckle up while driving badly.


To be fair it's the American DOT/NHTSA that thinks that. European-spec airbags are designed to work in conjunction with seatbelts whereas US-spec airbags are designed to work without seatbelts. That how it's mandated for the US market by the DOT/NHTSA; cars must have a passive restraint system. Initiallly motorised seatbelts were allowed; now it must be via airbags. It's the US government protecting people from themselves. I'm sure the automakers would gladly standardise on one spec but the US makes unique demands.


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## bbkat (Oct 27, 2002)

salvo said:


> BrettInLJ said:
> 
> 
> > I just got mine removed today. This guy has done them before and has been working on BMW's for 25 years (Bob @ All German Auto in Escondido, CA) and the shop has a great rep. according to other posts.QUOTE]
> ...


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## kyle5574 (Aug 26, 2003)

DZeckhausen said:


> BMW parts CD says the 328i does NOT have a CDV. So far, I haven't seen a 328i that did.


Whoops. I've been blaming most of my poor shifts on a CDV that most likely isn't there. I hope my friends don't find out. :eeps:


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## 330soon2b (May 30, 2004)

I left Dr. Z a message about a month ago (answering machine stated they were at a brake training seminar) and never heard back. Hmmmm.


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## DZeckhausen (Mar 11, 2003)

330soon2b said:


> I left Dr. Z a message about a month ago (answering machine stated they were at a brake training seminar) and never heard back. Hmmmm.


Two possible explanations. I'll occasionally get a phone message from someone with such poor audio quality (or strong accent) that I can't determine the number to call back. Also, following a clinic or a long race weekend, I will get very backlogged on calls and emails and it's possible your call simply slipped through the cracks. Best was to reach me is to email [email protected] or try the phone again.

Sorry for the difficulty you've had reaching me.


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