Does the e92 M3 have a Clutch Delay Valve?!?!

[rawedge2]

i asked about removing the CDV valve in this thread and recieved good info bout how members have done it and feel improvements in
This thread:
http://www.m3post.com/forums/showthread.php?t=137608

and now came across this, that it dosen't exist..
here:
http://www.m3post.com/forums/showthread.php?t=153462

clarification..?? since i haven't attempted the mod yet

[rmashman]

In the message above, there is a link to my original post.

In this previous post, I note that the M3 part that I got from my dealer was a clear pipe without the valve inside.

The part did not have any painted marking on it like the 335 valve. The 335 pipe looks identical on the outside to the M3 part except that it has a very noticable white painted number 25 and two bands painted around the part.

I did have a chance to take off the transmission cover on my car and did observe the that the pipe at issue has no markings like the M3 pipe gotton from my dealer as opposed to the 335 valve pipe which has painted markings. I take this as further evidence that there is no CDV valve.

Perhaps the member who took their part off of the M3 could measure the inside diameter and let us know what the measurement is. If it is 4mm plus there is no CDV in the housing.

Rob

[BPMSport]

Yes it does have a clutch delay valve, called a "lock valve". I removed it and the shifting is much crisper now.

[GregW / Oregon]

Originally Posted by Mike Benvo

Yes it does have a clutch delay valve, called a "lock valve". I removed it and the shifting is much crisper now.

Here it is in the diagram, #13 lock valve, but I haven't checked mine yet. I removed mine on the E46, but the difference was negligible, IMO.

[DJ9]

Originally Posted by Mike Benvo

Yes it does have a clutch delay valve, called a "lock valve". I removed it and the shifting is much crisper now.

You removed this yourself? DIY write up possibly

[GregW / Oregon]

Originally Posted by DJ9

You removed this yourself? DIY write up possibly

Hey, you unscrew it, take it out, and reconnect. Only thing is you need to bleed the system then. Also, slight chance, but clutch replacement under the BMWNA maintenance plan could be denied.

This is for the E46 M3, but basically the same (thanks to Mike):

http://m3.madrussian.net/diy_cdv.shtml

http://m3.madrussian.net/diy_brake_bleed.shtml

[1ne]

Greg you got the best technical pictures. Mind sharing where you are getting this?

[DJ9]

Originally Posted by GregW / Oregon

Hey, you unscrew it, take it out, and reconnect. Only thing is you need to bleed the system then. Also, slight chance, but clutch replacement under the BMWNA maintenance plan could be denied.

This is for the E46 M3, but basically the same (thanks to Mike):

http://m3.madrussian.net/diy_cdv.shtml

http://m3.madrussian.net/diy_brake_bleed.shtml

Thanks again Greg.

[lucid]

I don't get it. The OP in that other thread clearly says that the part is simply acting like a connector and does not have a valve inside like the E46 CDV's had. So, what does removing the connector change exactly?

[J08M3]

This is kinda strange. Half the people say they've changed it and it makes a difference and the other half the people that have taken it out say there is no valve in there. If you ask me, my car drives great and I have no problem with the clutch. So even if there is a CDV it certainly isn't causing any problems for me.

[Mickb]

Originally Posted by J08M3

This is kinda strange. Half the people say they've changed it and it makes a difference and the other half the people that have taken it out say there is no valve in there. If you ask me, my car drives great and I have no problem with the clutch. So even if there is a CDV it certainly isn't causing any problems for me.

Its a classic example of internet placebo effect. These boards (and others I might add) are littered with examples of people changing minor stuff on their cars and claiming massive differences (when I suspect in a blind testing of two cars they would not be able to tell the difference).

And the E46 cdv thing always surprised me anyway. Virtually noone in Europe (where 99% of people learn to drive with MT's) did the mod (or felt it was required), whereas loads of people in the US (where 99% of people learn to drive autos) claimed the stock transmission was rubbish and the cdv removal was essential.

Mick

[J08M3]

classic example of mind over matter?

[lucid]

If the connector does not result in reduction of cross-section, and thus, impedence of flow, there can be no real effect...rmashman is saying he took the connector out, inspected it, and observed that it was just a hollow connector.

So we have:

a) rmashman is mistaken
b) other M3s have different type of connectors/parts than the one rmashman investigated
c) others who have taken the connector/part out and claim they are experiencing an effect are the cause of the effect and not the connector/part in question

I'm kind of leaning toward c here, but all three are possible I guess.

[GregW / Oregon]

Originally Posted by lucid

If the connector does not result in reduction of cross-section, and thus, impedence of flow, there can be no real effect...rmashman is saying he took the connector out, inspected it, and observed that it was just a hollow connector.

Why would BMW install it if it has no effect? It is not needed as a "connection", as the hydraulic hose will connect fine without it.

[lucid]

Originally Posted by GregW / Oregon

Why would BMW install it if it has no effect? It is not needed as a "connection", as the hydraulic hose will connect fine without it.

I don't know. I haven't seen the hose and the connector, so I can't say what it might or might not be doing. Are you sure the hose would be just as secure without it? Again, if there is no change in cross section, I don't see how it can impede the flow. Have you seen it? Is there really no reduction of the diameter throughout the connector? Well, I guess the connector wall might have a different surface finish than the finish of the hose, but that should be an insignificant effect. Another possibility is that the hose might need to have some slack in it to meet some spec, and they don't want to manufacture a specific hose for the M3, and the are using the dummy connector--if that is indeed what it is--not to strain the hose. Many possibilities...

[SanFranciscoM3]

Hey guys, has this issue been resolved? Is the CDV a thing on the e9x m3 and will its removal help with mushy clutch pedal feel?

I have a 2008 that since new has had issues that sound like what the 335 people talk about with the cdv. I got the ucp and the bmw clutch stop which helped, but not totally. 20 plus years experience driving a stick, and the pedal has a mushy feel that sounds just like what the 335i people are talking about.

Maybe some years of m3 have it and some don’t? Mine is a 2008 e92, one of the early ones in production. They apparently changed the clutch in 2009+ M3s. I’m considering doing the cdv delete mod.

[NiBe]

I don't think that M3 has CDV. Compared to non M3 E9x. I have removed CDV from my E91 and it was a night and day difference witch clutch pedal. But I don't feel anything similar on clutch pedal with M3 which supports my idea that there is no CDV. And if there is I bet that it has the inner part removed which makes it just a tube which does not block any flow of the hydraulic fluid. So I don't think that CDV is a thing on M3. https://www.realoem.com/bmw/enUS/sho...diagId=21_0208 number 13 (CDV) in the diagram.

The CDV has inner part, it is basically a tube inside a tube. When you do CDV delete you can either remove the CDV completely or you can push of the inner part off. The result is the same - no hydraulic fluid restriction. Some prefered the second method because it is not visible from outside by BMW mechanics (warranty thing).

I think that I have even read it somewhere that M3 has CDV with the inner part removed aka M3 has no CDV. So again CDV is not a thing with M3.