[EvanL]

Hey, just removed the CDV from my 335i today. Very straightforward and much simpler than the CDV removal from my E46 M3. Steps are as follows:

1. Jack the front end up and put it on JACK STANDS. Do not get under a car that is supported by a jack only.

2. Remove the 6-or-so 8mm screws that hold the center underpanel in place. This should be the one under the transmission, with the air vent in it.

3. Release the clips from the CDV inlet, and the CDV outlet (actually the regular clutch line adapter). These clips are just small, paper-clip like clips that you'll see on some electrical connections (at least on older BMWs).

4. Remove the CDV, and install the rubber clutch line directly into the CDV adapter. Replace the spring-clip on the adapter.

5. Use a 7mm box key wrech and a friend to bleed the clutch valve. Be sure to pump the clutch a few times to get the air out of the system and into the bleed valve inbetween bleed sessions. 2-3 times should be ample.

6. Replace the aerodynamic underpanel.

7. Lower the car, and enjoy your new CDV-less shifting!

-Evan



EDIT: See post #19 for pics.

[shimshimhada]

Pics man! CDV-delete FTW!

[EvanL]

Note: I just realized there is a seperate DIY/Maintenance sub-forum. Could one of the mods move this for me? Thanks.

Oh, I should have pics within the next day or so.

-Evan

[DerekS]

Originally Posted by EvanL

7. Lower the car, and enjoy your new CDV-less shifting!
-Evan
BTW- I'll try to post some pictures I took of the clutch lines in the next few days if anyone needs them.

Evan,
After removing the CDV, what is the effect on clutch operation ?
What impact do you think this could have on the longevity of the clutch ?
Impact on warranty ?

T

[shimshimhada]

Originally Posted by DerekS

Evan,
After removing the CDV, what is the effect on clutch operation ?
What impact do you think this could have on the longevity of the clutch ?
Impact on warranty ?

T

http://www.zeckhausen.com/CDV.htm

Cliffnotes:
1. Direct clutch modulation possible
2. Lengthens clutch life significantly
3. They will never know, even if they did, they would have to prove that it somehow caused the problem at hand.

[BeeEmDubU]

Originally Posted by shimshimhada

http://www.zeckhausen.com/CDV.htm

Cliffnotes:
1. Direct clutch modulation possible
2. Lengthens clutch life significantly
3. They will never know, even if they did, they would have to prove that it somehow caused the problem at hand.

so what are the downsides then?

[shimshimhada]

Originally Posted by BeeEmDubU

so what are the downsides then?

There are none. Well, I got some brake fluid in my eye, but that washed out.

[DFW_M]

Originally Posted by shimshimhada

There are none. Well, I got some brake fluid in my eye, but that washed out.

Hmmm, so why are they putting it in...just to waste another $0.50?

[shimshimhada]

Originally Posted by dr325i

Hmmm, so why are they putting it in...just to waste another $0.50?

The purpose of it is to protect noobs from burning up the clutch, however, it's only detrimental to people with standard experience.

[Neurorad]

Has anybody had any mechanical problems after modding/replacing the CDV?

The Zeckhausen web page stated the e39 M5 didn't come with this CDV. Why does BMW put this in newer M3 and M5 cars?

[alaloom]

Thank you Evan, I am interested in doing this, some pics will be greatly appreciated.

[petesamprs]

Originally Posted by shimshimhada

http://www.zeckhausen.com/CDV.htm

Cliffnotes:
1. Direct clutch modulation possible
2. Lengthens clutch life significantly
3. They will never know, even if they did, they would have to prove that it somehow caused the problem at hand.

Shim,
Regarding #3, they can easily tell if you actually REMOVE the CDV (which this DIY describes). Any transmission problem can then be attributed to its removal, since it's an obvious part that will be missing. You should in theory install it back if something comes up.

Some people like me have gotten the CDV modified (wider opening) to avoid any warranty issues. Had Zeckhausen do it.

Originally Posted by shimshimhada

The purpose of it is to protect noobs from burning up the clutch, however, it's only detrimental to people with standard experience.

I believe the CDV actually protects the transmission at the expense of the clutch, by slowing the linkup between the engine and tranny. So it's more to protect noobs from destroying the rest of the tranny by resulting in slower clutch linkage (more friction wear) if you try to drop the clutch at 6k RPM.

The modification opens up the opening in the CDV to allow for a faster clutch takeup without the "delay".

[Chesmu]

is the process the same (more or less) for the e90?

[shimshimhada]

Originally Posted by petesamprs

Shim,
Regarding #3, they can easily tell if you actually REMOVE the CDV (which this DIY describes). Any transmission problem can then be attributed to its removal, since it's an obvious part that will be missing. You should in theory install it back if something comes up.

Some people like me have gotten the CDV modified (wider opening) to avoid any warranty issues. Had Zeckhausen do it.




I believe the CDV actually protects the transmission at the expense of the clutch, by slowing the linkup between the engine and tranny. So it's more to protect noobs from destroying the rest of the tranny by resulting in slower clutch linkage (more friction wear) if you try to drop the clutch at 6k RPM.

The modification opens up the opening in the CDV to allow for a faster clutch takeup without the "delay".

I have the modded cdv installed in mine too. It's easier if you have the modified one, but the delete is fine. In any case, it's noob protection.

[Chesmu]

hey shimm...

what there's no Veyron forum so you have to join this one? LOL

[shimshimhada]

Originally Posted by Chesmu

hey shimm...

what there's no Veyron forum so you have to join this one? LOL

I should make one.

[Chesmu]

yeah...there would three of you on there....

and the mods would be PRICEY.....

[rkg]

Evan,

Please post some pics whenever possible. I should be receiving a modified CDV from dave zeckhausen that I picked up in Munich and had pinged him about installing the valve in a e90. He personally had never done it but made is sound like it was not that difficult unless it was like a 530.

That said and before crawling under the car, any pictures or tips would be greatly appreciated.

Regarding clutch bleeding, did you have to add fluid? If so, just DOT 3?

Thanks.

[EvanL]

Pics are shown below:

Here is the clutch line minus the CDV. Note the exposed clutch bleed valve in the distance:


This is the removed CDV next to the modified hydraulic line. This shows approximately where the CDV would be on a stock car:


Here is the removed CDV, showing the spring clip that must be unfastened to remove it:



Hope this helps.

-Evan

[EvanL]

Originally Posted by rkg

Evan,

Regarding clutch bleeding, did you have to add fluid? If so, just DOT 3?

Thanks.

Nope. You may have to add fluid as your brakes wear to the point where they need replacement, but you'll get an idiot light on your dashboard at that point anyhow. Note that it wouldn't hurt to check your brake fluid resoviour anyhow.

-Evan

[EvanL]

Another side note: If you ever plan on tracking your car, REPLACE the stock fluid with Motul RBF 600. More expensive than ATE Blue or the BMW stuff, but well worth every penny.

Take that from a DE instructor and Mechanical/Nuclear engineer with a lot of experience in overheating brake systems.

-Evan

[EvanL]

Final side note (wish I would've just thought of these at the same time): Expect a small DIY for the BMW MOST iPod adapter within the next few days.

-Evan