Clutch delay valve mod

B

blowers

Member
Buckinghamshire
Have read some posts on this mod and am considering whether to ask my indy to do it for me.
I am not exactly clear what the "downsides" are if any. Still getting used to my car but I do not feel the gear changing is all that smooth. (OK admit to having driven aotos for the last umpty ump years but I am trying hard!)
Other mods considering: ZHP shorter shift gear knob and removing rear foam on sound generator.

Would I be right to assume that none of these mods would need to eb advised to insurers???
Downsides to CDV mod??
 
Thanks -so what exactly is it there for and should the mod be declared to Insurance co -or is it not considered "performance enhancing" ??
 
its put there to protect your gearbox i guess

have you googled it ,just try that and you will find the answers

i dont think removing is ups the performance do you?
 
Have a look at this - it's a cheapand easy mod to do and certainly a big improvement in terms of 1st/2nd gear changes :thumbsup:

http://www.z4-forum.com/forum/viewtopic.php?f=25&t=1227&hilit=clutch+delay+valve

And this:

http://www.zeckhausen.com/cdv.htm
 
Thanks Alan
The best description I have found is below. I don't quite understand the real reason it is there in the first place i.e. quote: "For people who don't drive properly and to reduce drivetrain shock" is to me perhaps a little vague and open to interpretation.
Sandere above suggests it was put there to protect gearbox but suggestion below is also that clutch wear is increased.

I wouldn't suggest (of course!) that I don't drive properly ......but at the same time having had autos for the last 100 or so years I would not say I am completely faultless in getting used to a manual again (and no I don't find the gear changing smooth which I used to with an MX5 I had as my last manual in about 1811) . Just trying to understand by doing this mod (or rather getting my indy to do it) am I running a very high risk of causing other damage/ expensive bills..or as it appears...small risk and one worth taking? (Low mileage and occasional spirited driving when missus is not around to complain) Comments appreciated. Thanks again

===================================

"The CDV (Clutch Delay Valve) mod removed the delay valve so that when you take your foot of the clutch the clutch is released at the rate you determine and not the rate of the valve.

No delay is applied when you put your foot on the clutch but it is when you take your foor off, it is there for people who cannot drive properly and to reduce drivetrain shock, but it will increase clutch wear and make changing gear smoothly very difficult.

It really is one of the best and cheapest mods you can do"
 
The CDV is removed by so many people, with Z4's 3 series, 1ers and I have never found anybody report a problem due to having it removed. I can really detect it in my 1er, I'm hoping my boss will let me remove it.
 
It just seems really odd to me that BMW persisted with the CDV on several models if there isn't a downside to having it removed.
As mentioned like most people I believe I am a reasonable driver ...but I ain't perfect... and I was wondering "what would I have to do with the CDV removed to cause serious problems to the drivetrain etc and high associated costs" Would appreciate your observations on "whats the worst that could happen?" with the CDV removed??.

I've googled this and the best one liner I have seen is "If you aint going to burn the tyres you won't have a problem" ............does that sum it up and the answer that I am looking for?


Thanks again
 
I need to do this mod - daft question though, where is the darn thing and how do you get to it? I've read a lot of threads on here about it but none that I saw actually told me where it is! Tried google but clearly I"m having a 'dull' evening!
 
A ramp or pit would be perfect, if not, lift from passenger side (UK spec car) remove front wheel, only for extra space and stand placement. Get under car between wheel and jacking point, CDV is sort of directly under the front of the passenger seat, next to the gearbox.

It really is a very straight forward job, but do pinch the clutch hose otherwise it will pi55 fluid.
IIRC, 11mm and 17mm open ended to loosen and remove the CDV which actually sits in little bracket thingy, undo the smaller end first and it'll just spin off by hand. Same spanners to connect the ends you are left with.

Bleed the clutch for a few pumps and you're done.
 
Lee, if you mean a proper ramp.........it'll take you 2 minutes max to do the whole CDV removal process. And another 2 to bleed the clutch. (the nipple is very near to the CDV.)

Access is the only enemy for this job.
 
That's great - I can get to a ramp this weekend so should be easy enough - although whatever timeline anyone ever puts on a job I generally double to allow for my natural ability to overlook the obvious!

I assume I can bleed it just by opening the nipple and pumping the pedal? Did hear talk of a special BMW tool but can't see how it would be needed for this.
 
Yep, straight forward bleed.....bit of tube, loosen off and a few pumps.....ensuring plently of fluid at all times in the master cylinder.
 
Downsides would be for anyone who is learning to drive manual on your car would likely stall it much easier. The CDV is there to close the clutch at a slower rate. It gives beginners smoother shifts and less chance of stalling the car.

With the CDV installed you can repeatedly stomp on your clutch in 1st gear quickly without applying gas and the car would not stutter or stall. With the CDV removed as soon as the clutch closes the engine would bog or die. In essence it slips the clutch.

A benefit of the CDV removal is if you're good at modulating your clutch, you should have a little less clutch wear.

Note to those with SMG's. The CDV is already removed as the computer determines clutch slip instead.
 
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