Z4 CDV removal

TaffZee

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Anyone done this mod? Any info appreciated. Car can be a little jerky when taking off if you don't take your time, and takes a while to really bite on the clutch during rapid gear changes just for a spit second, Are these all CDV related issues?
 

TR4man

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I've thought about this as well but decided against it as a benefit of leaving it alone is that it cushions your drivetrain if you tend to be brutal with the clutch


However, if you do decide to go ahead you may find this short film useful

View: https://www.youtube.com/watch?v=PoB5ORUMdnE


They show how to install a modified CDV, but you don't need to do that once you've removed the old one, and can just connect the hydraulic hose directly to the mounting bracket.
 

TaffZee

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Under normal driving conditions it is fine but the consensus is that the car performs better and smother without it, spirited driving is effected though as during quick changes and take offs there is a very slight delay in the clutch biting fully leading to a slight clutch slip which must reduce the clutch life. It is on my radar to do this mod ASAP, as the delay is apparent and is annoying.
 

GazHyde

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It's exactly the same reasoning behind doing it on the Z3 Jim, get on with it! I would personally take any potential negatives over the smoother gear change. Need to sort it on my Z3, just haven't had the time or cash to do it yet. Didn't need it on my Z4 cos that was an auto... ;)
 

MartinN

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I was hoping this would come up, is it true that not all Z's have this, I seen to recall a list and the 2.0Ltl 6 pot didn't have one. I'm about to get mine of the axle stands so could check, but it's cold on the drive. Has anyone got any deeper knowledge on this?
 

TaffZee

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It's exactly the same reasoning behind doing it on the Z3 Jim, get on with it! I would personally take any potential negatives over the smoother gear change. Need to sort it on my Z3, just haven't had the time or cash to do it yet. Didn't need it on my Z4 cos that was an auto... ;)
Gonna do it ASAP Gary, but a few different opinions are about, do I remove it completely http://www.diymybmw.com/e46/clutch-delay-valve-cdv-delete/ or Mod the one on it and replace it????
 

GazHyde

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I would personally go with the Earls braided clutch hose option. Better all round. Although if you want the stealth look you could modify the existing one I guess.
 

TaffZee

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I would personally go with the Earls braided clutch hose option. Better all round. Although if you want the stealth look you could modify the existing one I guess.
Good point Gary, don't suppose anyone knows the part number for the Earls Braided Clutch Hose?
 

Lee

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Did you do this @TaffZee? I'm finding the same issue with my z4.
 

Dino D

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Get it done guys, had it in a 330i and thought I had worn clutch when doing 'standard' launches from the lights in London.

It's done on my Z and what a difference (but being a Z3 its a proper car with cable between throttle and pedal ;) )
None of this softy softy fly by wire business...
 

Brian H

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I stripped the CDV out of my 3.0, it's just an inline fitting, you can either remove it all together or enlarge the hole in the CDV, no more slipping the clutch.
 
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GazHyde

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I've just rung Earls and they don't have a pre-made braided clutch line for the Z4, even the sales guy on the phone was surprised. They can make one up if we supply a donor hose, so I may just order an OEM one and send it over. They should be able to part number it then and make purchasing easier for everyone else.

Alternatively as Brian said I could just modify the existing line and remove the delay valve. Will post up details of however this goes from here on...
 

Lee

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I guess they are the same as the Z3M it fits inline so undo the fitting/remove and re bleed the clutch.
 

Lee

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We did it :) removed mine and garys in about an hour. @TaffZee you need to do this.
 

GazHyde

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What a difference, in particular now bad gear changes can only be blamed on me. Mine tended to slip/judder in first pulling away, and slow rolling in second at junctions/roundabouts was just mind destroying.

Oddly the car feels much more like driving my Z3 as the gear changes are just better. It's just even better now!

Was easy enough to get to with the side of the car jacked up. Passenger side access slightly easier than drivers side, and the clutch bleeding process carried out painlessly too.

Pictures for reference as the shape is slightly different from the pics Brian posted.
upload_2016-4-9_18-31-24.png


upload_2016-4-9_18-30-51.png


upload_2016-4-9_18-31-7.png
 

Alastair

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Anyone done this mod? Any info appreciated. Car can be a little jerky when taking off if you don't take your time, and takes a while to really bite on the clutch during rapid gear changes just for a spit second, Are these all CDV related issues?
I used to own PJ05 HMY, I already carried out this mod before I sold it..

Looks alot better with blackout kidneys etc :)
 
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