[andret]

I am about to have the CDV mod done on my E90 325i 6MT using a CDV replacement valve ordered from Zeckhausen Racing in the US (http://www.zeckhausen.com/cdv.htm).

I would like to know if anyone has done this to an Australian E90 Manual and what their experiences were. It seems that there are not many E90 Manual's here and I haven't yet heard anyone else doing this here.

[mark325]

Hey I'm keen to do it as well, Let us know how it goes.

[OZ!MSport]

I have thought about modding my CDV - but to be honest I haven't experienced the so called 'clutch delay' - or at least, it hasn't caused me enough grief to bother modding it.

I'm interested to hear if it improves your gear shifting.

[mark325]

Just drop the clutch from 2nd to 3rd and you will see it working :P

[andret]

Have been frustrated with this from when I bought this new over two years ago. Didn't know what the problem was. Have been driving manual for over 15 years, but this car just didn't seem right. After doing some research (e90post is good for this), found out about the CDV. Seems I wasn't the only one frustrated with this.

With the CDV, clutch/throttle modulation is not possible. The clutch will engage a delayed time after you begin releasing the pedal, not at the friction point of the pedal as in most other manual's. This is due to the restricted valve opening for clutch engagement limiting the speed that the clutch can be engaged. It is like there is some other force at work since the engagement of the clutch is not directly related to pedal position. Sometimes the pedal is almost fully released and the clutch then fully engages, catching you off guard as it should have already engaged. Very embarrasing if you have passengers who are quitely thinking that you simply can't drive a manual properly.

I admit that when keeping revs low around town, this makes little difference, and it can be bearable. However when driving these cars as they should be driven, it is very difficult to get the smooth performance out of them that you know should be possible.

Will keep you all posted on the details.

[andret]

Getting CDV installed tomorrow at BM Connections.

Here is a picture of the part from my camera phone. Will take some pics during install tomorrow.

[andret]

It's done!!! Had the Zeckhausen CDV installed today. The result is amazing, the car feels totally different to drive. It is like I have been driving with a numb left leg for the last two years, now the feeling and control is back. This is the easiest way to improve the drivability of your late model BMW manual.

I am still stumped why BMW insists on putting this in to their manuals. If you cannot smoothly drive a manual, then you should get an automatic. Why penalise those who have the ability to control a clutch with this ridiculous restriction to forcefully slow the clutch control. With the new CDV, it feels like a real clutch with immediate response. It is no wonder why this is not included in the new M3.

Technically, it looks like the internal diameter of the old valve is about a THIRD that of the Zeckhausen valve. For those who do not know much about fluid dynamics, this reduces the flow by a factor of 10. I cannot believe how small this is, no wonder the clutch action is so delayed.

I will post some pics that the mechanic took once he sends them through. Must thank Simon Yeates from BM Connections for completing this work for me.

In summary, I highly recommend this modificaiton. Simply order the part from Zeckhausen Racing in the US (http://www.zeckhausen.com/cdv.htm), wait about one week for delivery via US postal service (total cost about $A100 for part and delivery). Go to your friendly BMW mechanic (not an authorised BMW dealer obviously) and get this changed out. It takes about 30 min and should not cost more than $60 for the install. You will not regret it.

[OZ!MSport]

Hmmm - thanks for the review...

[MFKN3]

Anyone else done this? I read on here the modified valve is just a stock valve that's had the plastic clip inside tapped out using a screwdriver. I'm not sure if this can be reversed though.

I suppose removing it or modifying it would have the same results, except the modified one wouldn't be noticed by bmw.

I haven't really noticed any trouble with the MT but perhaps I have become used to it? Keen to hear other peoples opinions whether it is worthwhile?

[CV335]

Originally Posted by xsboost

I haven't really noticed any trouble with the MT but perhaps I have become used to it? Keen to hear other peoples opinions whether it is worthwhile?

I did the CDV delete a while back. Honestly, I think there is more of a placebo effect than anything else. I can barely tell the difference in the clutch response...maybe if I had arthritis on my knees I would be able to discern the "improvement"