CDV (Clutch delay valve) delete mod

Six6siX

Six6siX

Six6siX

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Saw this linked to the other day and been reading around as I have been jumping around slightly on the odd occasion from 1st and 2nd gear.

Has anyone here done this and felt any benefit - also advantages/disadvantages? I know there is a lot of info on other forums but thought I'd ask here for anyones 1st hand experience.

Its something I'm looking to do along with the exhaust flap mod.

(inb4 learn to drive etc :p)
 
MikeHiow said:
I'd imagine it does what it says on the tin?

These are there to try and stop it being jump, so I'm not sure how far removing it would be.
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Well from what I understand they delay the clutch engaging (slipping it effectively) by restricting the flow of fluid to try and give a smoother movement. But many have found, myself included tha it causes the judder and jerky gear changes as it makes the clutch action unpredictable compared to a 'normal' clutch.

People who have removed them say that starts from 1st and gear changes are much smoother without the valve but could put potential extra strain on the drive train if you dump the clutch at high rpm (which is pretty unlikely tbh.. :p)

And also increase the life of the clutch as there is much less slippage.

But I'm in two minds whether to just suck it up and try and get used to it or just remove it - hence wanting people's experiences.

[TW]Fox;16867455 said:
It seems to be these purely to annoy people.
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You mean the valve is an annoyance?
 
I can't look under my car to be sure but I'm 50/50 sure, not sure I actually have it. When it goes for it's first service I will definitely remove it if I do have it though. I have to slip the clutch more than my previous car to take off in 1st and if I get it wrong it isn't a smooth affair pulling off (yes I can drive)

Also if I take it out of 5th, 90% of the time the stick won't reset in the neutral position which apparently changing to redline transmission oil and part # 23117542726 resolves.

At the next service I'm hoping all 3 above will fix any clutch judder, notchy gear change issues I have, maybe for you too :)
 
[TW]Fox;16867660 said:
BMW replaced my entire gearbox under warranty for that not returning to centre when changing out of 5th thing.
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niice, but it's no wonder parts are so expensive though, a $5 bushing apparently fixes it rather than a whole new gearbox :eek:
 
Oxide™ said:
niice, but it's no wonder parts are so expensive though, a $5 bushing apparently fixes it rather than a whole new gearbox :eek:
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I heard it's a gearbox out job to replace the parts though.

I fixed mine with a gear oil change. BMW are clueless if they really think the oil is lifetime and doesn't need to be replaced ever.
 
Oxide™ said:
Are you getting it modified or removed? I would be very interested in the difference you feel :)
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Getting it modified. I have read great things about it being removed or modified over standard on Z4's, most people can't understand why it's there to begin with.

I will let you know. I have to bed my new brake setup in tonight, so should get a good feel for the new gear change.... :D
 
Booner! said:
My car is currently having the CDV modified......will report back

:)
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Interested to hear your view post-mod!

I think on some models you can have it removed entirely as the pipes are flexible and so easy to manouver to compensate for the missing valve but some are not so easy to bend which requires modifying one for a better fit.

There is a guy/trader on one of the US forums I think who sells the modified PCVs for about $35, says they arent drilled out (as this damages the ends and could cause leaks) but uses a different method...or something like that.

edit:

Over Clocker said:
Got my CDV removed on my old 320i E46. Was a massive improvement :)
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Excellent to hear, have you had any issues related to removal? How do you find the gear changes and 1st gear moving off in comparison?
 
Last edited:
Just quick bump on this thread.

I've just removed the CDV on my 130i. Even with my limited mechanical skills it was a very easy to do mod.

It took about 15min to do and most of that was removing / refitting the undertray - o and a quick trip to the bathroom to wipe the brake fluid off my eyelid :D

Anyway the difference that it has made to the engagement of the clutch is amazing. It's now possible to change gear smoothly, especially in the lower gears. It's made the car so much smoother to drive I can't believe they even fit the valve in the first place, completely crazy.

Anyone who owns a BMW with the CDV needs to remove it, it's so simple and the difference is astonishing. :)

Guide I used; Clicky
 
My S2000 has a CDV and reports are it's there for a reason (eg - stopping you dumping the clutch in at 9,000RPM). Some people say it helps with fast changes but others say it's next to no difference. I guess the BMW implementation is much harsher.

I don't notice it at all so have not felt a need to remove it. Maybe I should try an S without one to see but I cannot see how I could improve my current gear change more :x
 
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