[magic77]

Just wanted to compare others experience with theirs.

I dont know if its just me going crazy but I've noticed that my gearbox has weird behaviour.

Shifting between gear can be very notchy when you try to shift into gear when you press the clutch. But only if you do everything quickly.

Usually 1st gear is most obvious. If you press the clutch and wait a second then engage 1st its smoother.

As if theres some delay system in place. Also noticable in higher gears especially if having slow lazy drive or stuck in traffic.

ANy thoughts would be appreciated.

Cars a 09 plate with 23k on clock

[willhollin]

Clutch delay valve?

[rogerxp]

I'd have said so. It's a right royal pain in the arse but can be removed (or modified) by many independents...

http://en.wikipedia.org/wiki/Clutch_delay_valve

It's a nightmare in my E46, near impossible to make a smooth 1 to 2 change...

[magic77]

thanks weird thing is I dont recall it being at all this bad in my e46 320D M Sport and that had a map up to 190

I wonder if birds can do this and whats the cost

[rogerxp]

Think places do it for about £20 but I'm not 100% sure - it's a tiny job (I understand), cut pipe, remove old CDV, insert new or modified CDV (with wider hole through the middle), stitch back up. Easy.

[JaySTee]

I am intending on getting rid of my CDV - supposedly a fairly straight forward mod. I believe on some models you can just remove it and the existing flexi clutch hose is long enough to connect direct to the slave cylinder. Alternatively replace with a valve with the internal restriction removed, bleed clutch, job done...

Anyone know a UK supplier for modded CDV's?

[CarAbuser]

I have noticed exactly the same behaviour, have to be really careful changing gears to get a smooth change. First gear is always a nightmare.

What are the downsides of altering the CDV?

[FieldingMellish]

CDV = Get rid!

I was in heaven the day Ant at Speed Religion removed my CDV. It was like getting rid of a kidney stone!

Only downside is you must warn people used to the CDV not to dump the clutch any more.

[satish_141]

Originally Posted by FieldingMellish

CDV = Get rid!

I was in heaven the day Ant at Speed Religion removed my CDV. It was like getting rid of a kidney stone!

Only downside is you must warn people used to the CDV not to dump the clutch any more.

How do I know whether I have a CDV in my car or not? and if needs to be changed...sorry if it is too basic question ?

[rogerxp]

Originally Posted by satish_141

How do I know whether I have a CDV in my car or not? and if needs to be changed...sorry if it is too basic question ?

My understanding is that if you have a manual BMW you'll have a CDV. Finding out whether yours has been modified (assuming you've bought a used one) would be a little more tricky - I guess there would be telltale signs of work around the area where the CDV is.

I don't really know what's involved so can't tell. Isn't there a 'pipe' with the CDV inside so you'd need to make a cut in the 'pipe' then seal up again somehow afterwards .

[JaySTee]

Link to E92 CDV change

It may differ slightly on E90/91 I guess.

Further reading

[JaySTee]

Useful info from first link above..

Originally Posted by DHarold

Easy CDV mod DIY, if you want to replace your CDV so it looks stock.

Set the CDV down on a flat hard surface, big end down. Use a flat end punch , no larger than 5mm diameter, insert through the small end and give it (the punch) a good tap. The orifice plate and the backup plastic part will pop out. The CDV is now completely open. No muss, no fuss, no debris.

Just found this out by accident. I got a replacement CDV, and was set to drill out the innards, but before any real drilling started, the force of the drill press pushed out the working parts. Since a replacement CDV is only about $5.50, this is a no-brainer.

[satish_141]

Originally Posted by rogerxp

My understanding is that if you have a manual BMW you'll have a CDV. Finding out whether yours has been modified (assuming you've bought a used one) would be a little more tricky - I guess there would be telltale signs of work around the area where the CDV is.

I don't really know what's involved so can't tell. Isn't there a 'pipe' with the CDV inside so you'd need to make a cut in the 'pipe' then seal up again somehow afterwards .

thank you. mine is a manual

[JaySTee]

I have now removed the CDV on my E91 and the clutch feels much better - how it should be LINK TO MY THREAD WITH PICS

[lemans 330d]

get an auto.

nice and smooth!!!

[magic77]

funny you should say that certainl considering it, though I think it would have to be at elast a 325D to make the auto work, I think on a 320D it might be to slow comparing to manual.