To CDV Delete or Not To CDV Delete

[echo46]

All
Been reading about the evils of the CDV and how it impacts shifting and overall drive feel. How many people did the CDV delete and how has it changed shifting. Should I get the modified valve from Zeckhausen racing for 50 bucks. Is it worth doing?

[danewilson77]

Don't get modified valve body.

Many have done it.

Shifting is surer.

HTC Thunderbolt+TT

[echo46]

Are you saying just to get rid of the valve completely or keep the CDV?

[Au2bahn]

Just remove CDV, re-attach clutch line, and bleed.

[GreenFrog]

Completely removed mine today. Night and day difference. For the better.

First to second never felt better/smoother.

Do it.

[echo46]

Am I in the minority still having CDV?

[echo46]

Do I need any parts or special tools?

[GreenFrog]

I got mine deleted at an indie mechanic's shop. Went in to get my alarm activated so I got the CDV deleted as well.

As far as I'm aware, it's a very easy job and takes like 15 minutes. If you search around the forum here, you'll find some threads that have links to DIYs. Seemed very straightforward to me, but I just don't have the tools and jackstand to do it.

[echo46]

Yep, just reading about it now, fairly simple. If I get some time this weekend I think I am going to CDV delete.

[danewilson77]

Yep, just reading about it now, fairly simple. If I get some time this weekend I think I am going to CDV delete.

You are in minority.

No special tools needed.

HTC Thunderbolt+TT

[kayger12]

Am I in the minority still having CDV?

Minority, yes.

Alone, no.

Mine is still in. Left it in while I was still under CPO.

Will be making its departure next weekend now that CPO is over.

Droid X. Tapatalk. Use it.

[RITmusic2k]

Assuming your car is out of warranty, there's no reason to get the Zeckhausen unit; its only purpose is to provide the CDV-delete effect while maintaining the look of a stock setup. You really don't need to worry about that.

The best tutorial I've seen so far:

http://m3.madrussian.net/diy_cdv.shtml

Doing it this way with the little c-clamps, I didn't even have to bleed the system after removing the unit. Car's perfect. Took me barely 20 minutes.

[kayger12]

^^^
Great link. That's the one I'm gonna use.

Droid X. Tapatalk. Use it.

[danewilson77]

^^^
Great link. That's the one I'm gonna use.

Droid X. Tapatalk. Use it.

It's the one I used when I did mine.

HTC Thunderbolt+TT

[webster]

i got the modified CDV from zeckenhausen and i got ripped off paying for the part+install. it was one of the first things i did for the car and i totally overpaid. that said, shifting is much smoother with the modified unit. although i kind of want to delete it completely and see if there's any additional difference...

[wsmeyer]

I picked up a SS clutch line on sale for $24 last week. I've wanted to do the CDV delete for a while and I figured since I have to bleed the line anyway...

Haven't had time yet but soon.

William.

[HokieZHP]

Is this reversible?

[Katu]

Is this reversible?

Sure. You just put the CDV back in. When you remove it, you don't cut/modify anything

[GT172I]

Agree with all of above. Annoyed I waited so long to take it out, was really easy and was a noticeable improvement. I also used the MadRussian DIY

[llll1l1ll]

I'm still in the minority... :/

I don't think I drive hard enough to notice goofy shifting. My downshifts are fairly seamless. The only time I notice goofy shifting is going from 1st to 2nd when I am freakin' rippin' it.

If I get a set of ramps I'll do it. My new apartment complex does not allow car repairs in the parking lot.

[aurelius]

I don't think I drive hard enough to notice goofy shifting.

Maybe your car doesn't have a CDV?

You'll really notice it most in slow parking lot-type situations. Or when trying to engage 1st gear on an incline.

As I posted in another thread yesterday, it's worth noting not all E46's have a CDV installed. I have had two 330's over the years and neither has had one.

[llll1l1ll]

I'm not sure if it does. Like I said, my downshifts are seamless. Starting on an incline is no biggie and maneuvering around a parking lot is a lot like my E30. The only time I noticed it was trying to shift quickly at high revs from 1st to 2nd. The clutch was a bit slow to engage, but that may have just been me getting used to it. I'm gonna try again today (heh heh heh).

[The-Traveler]

I'm not sure I see the point. Sure, when the car was new to me 1st to 2nd was a problem.. which suggests that I have the cdv still. But, I'm completely used to it now and my shifts are perfect.

Why take it out and cause more stress on the drive train when you could just get used to it?

I have no problem making buttery smooth shifts in all situations. Don't mean to sound like a douche here, but perhaps some of you guys aren't pressing in the clutch all the way. The bumb stops are not smart, as I've found my car needs 100% of the pedal travel to completely disengage.

Another point... I was teaching a friend how to drive stick recently and I'd say the cdv was helpful in preventing stalls. He may have stalled once, in 30 start-stops that we did that day.

Anyway that's my 2c.

[aurelius]

T-T:

20 bucks says yours doesn't have a CDV.

[Katu]

T-T: Sure the CDV might help a new driver, but most of us aren't just learning stick.

When I took out my CDV it wasn't huge, but I noticed the difference. Seemed worth it for such a simple/quick fix.

[webster]

i don't think removing or modifying the CDV puts any more stress on the drive train, at least not in daily driving. maybe if you're redlining around town a lot...

[jreyes19]

I am with the minority but i will soon be within the majority
if i get a little bit of time this weekend lol

[aurelius]

i don't think removing or modifying the CDV puts any more stress on the drive train, at least not in daily driving. maybe if you're redlining around town a lot...

It's there to reduce warranty claims from those who dump the clutch at high revs and or otherwise drive poorly and then decide they want BMW to pay for a new clutch.

[carsontl]

all you smart guys, can someone fill me in what the CDV actually does?

[danewilson77]

all you smart guys, can someone fill me in what the CDV actually does?

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

HTC Thunderbolt+TT

[carsontl]

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

HTC Thunderbolt+TT

omfg i just thought I was an idiot when first gear would jerk like crazy making me feel like a mosh pit... kept thinking it was me!!! that CDV is coming out asap.

[danewilson77]

omfg i just thought I was an idiot when first gear would jerk like crazy making me feel like a mosh pit... kept thinking it was me!!! that CDV is coming out asap.

LOL......it will liberate....and set you free!

[MrMaico]

omfg i just thought I was an idiot when first gear would jerk like crazy making me feel like a mosh pit... kept thinking it was me!!! that CDV is coming out asap.

Where I mostly noticed it was on a lazy 1-2 shift if you didn't get the clutch release right the car would get a jerking going on briefly.

On the advice of a mechanic at work, I just did a gravity bleed on mine rather than pumping the clutch to bleed it. Just hook up a hose to the bleeder and let it drip for a bit to bleed any air. Simple, and it can be done without having to have a helper on hand.

Barry

[Oli77]

I'm not sure I see the point. Sure, when the car was new to me 1st to 2nd was a problem.. which suggests that I have the cdv still. But, I'm completely used to it now and my shifts are perfect.

Why take it out and cause more stress on the drive train when you could just get used to it?

I have no problem making buttery smooth shifts in all situations. Don't mean to sound like a douche here, but perhaps some of you guys aren't pressing in the clutch all the way. The bumb stops are not smart, as I've found my car needs 100% of the pedal travel to completely disengage.

Another point... I was teaching a friend how to drive stick recently and I'd say the cdv was helpful in preventing stalls. He may have stalled once, in 30 start-stops that we did that day.

Anyway that's my 2c.

I'm with you on that one. Got used to it and for daily driving around town it is fine (to me). The only time I can tell the engagement is delayed and it "rides" the clutch a bit is when I do those hard accelerations with a 1st to 2nd shift. I rarely do that so I'm in the same boat as you and I'll keep my CDV in.

I also tend to agree that removing the CDV may increase strain (rapid torque changes) on the drive train.

My 1.5 cents.

[llll1l1ll]

I don't think mine has it, or else I'm just so used to it.

[zj96sc]

First ZHP had one, 2nd does not. Night and day difference.

The only way deleting the CDV is going to increase stress on your driveline is if you're dumping the clutch or generally suck at driving a manual.

[echo46]

Great stuff guys, I'm convinced. Boy, once that insidious valve is deleted I will be rocketing up and down the Long Island Expressway--well maybe not as it is commonly referred to as the Long Island Parking Lot.

[edlvrt]

In addition to smoother up shifts, I really noticed an improvement when quickly downshifting.