DIY - E92 CDV (Clutch Delay Valve) Removal - BMW 3-Series (E90 E92) Forum

DIY - E92 CDV (Clutch Delay Valve) Removal

Published by EvanL
09-13-2006

DIY - E92 CDV (Clutch Delay Valve) Removal

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.

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By shimshimhada on 09-13-2006, 02:39 AM

Pics man! CDV-delete FTW!

By EvanL on 09-13-2006, 02:40 AM

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

By DerekS on 09-13-2006, 02:59 AM

Quote:

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

By shimshimhada on 09-13-2006, 03:00 AM

Quote:

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.

By BeeEmDubU on 09-13-2006, 04:11 AM

Quote:

Originally Posted by shimshimhada

so what are the downsides then?

By shimshimhada on 09-13-2006, 04:17 AM

Quote:

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.

By dr325i on 09-13-2006, 09:32 AM

Quote:

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?

By shimshimhada on 09-13-2006, 09:45 AM

Quote:

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.

By Neurorad on 09-13-2006, 10:15 AM

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?

#10

By alaloom on 09-13-2006, 10:24 AM

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

#11

By petesamprs on 09-13-2006, 12:49 PM

Quote:

Originally Posted by shimshimhada

Quote:

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".

#12

By Chesmu on 09-13-2006, 02:14 PM

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

#13

By shimshimhada on 09-13-2006, 02:37 PM

Quote:

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.

#14

By Chesmu on 09-13-2006, 02:40 PM

hey shimm...

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

#15

By shimshimhada on 09-13-2006, 02:45 PM

Quote:

Originally Posted by Chesmu

hey shimm...

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

I should make one.

#16

By Chesmu on 09-13-2006, 02:48 PM

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

and the mods would be PRICEY.....

#17

By rkg on 09-14-2006, 01:38 AM

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.

#18

By EvanL on 09-14-2006, 04:35 PM

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

#19

By EvanL on 09-14-2006, 04:37 PM

Quote:

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

#20

By EvanL on 09-14-2006, 04:42 PM

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

#21

By EvanL on 09-14-2006, 04:47 PM

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