Anyone regret the CDV mod?

[PatJags156]

Anyone out there that regrets doing the CDV mod or someone that has great reasoning as to why they didn't do it, besides the car's warranty.

I am seriously considering this mod but want to hear more testimonials as to why or why not.

[Diokaef]

No repentance from me, done on two of my MC

[thekurgan]

Considering the device shouldn't be there in the first place, I don't think you'll get many who regret it, unless a warranty issue has arisen for the individual.

[a_riddler]

Only reason I could see not doing it is you are under warranty and you don't want to spend $35 bucks for a placeholder

http://store.zeckhausen.com/catalog/...dv-007&x=0&y=0

Zeck CDV for warranty issues and you are good.

I think another reason is that you might not be comfortable doing it yourself, if so, minor labor costs to do it, but an additional cost to consider.

[PatJags156]

You are right, I am nervous about doing it myself, but also I am afraid of damaging the clutch and trans in the long run with this mod.

I have a very notchy 1st and 2nd and I am afraid the CDV mod will make this worse.

[Diokaef]

I had the dealer doing it for me, and about 1st and 2nd that goes the other way around.

[nickpapa]

i didnt notice any change. and i bled the clutch after too.

it was very simple to swap out but i dont know if id do it again since it really didnt make a difference to me

[Ron Stygar]

Originally Posted by nickpapa

i didnt notice any change. and i bled the clutch after too.

it was very simple to swap out but i dont know if id do it again since it really didnt make a difference to me

Me too.

With a proper bleed with the CDV it's the same without.

Maybe you have to beat on it to see the difference.

When you install the CDV and the pedal goes down easier there is air in it.

[r4gs]

i had the zeckhausen cdv installed in-place of the stock cdv about a month ago, and it has made a noticeable difference in terms of clutch engagement. i.e., less jerkiness in the lower gears and smoother transitions into higher or lower gears. what it will NOT address is the issue of 1 and 2 notchiness in shifting (which i still have).

[Finnegan]

No regrets. With the Zeckhausen CDV, the CDV is still on the car (rather than a delete) and since the Zeckhausen looks stock it's not going to raise any red flags at the dealer. (I doubt any tech at the dealer would know the difference between stock and Zeckhausen anyway even if they looked.)

With the CDV effectively removed it's much easier to modulate the clutch in 1st and into second and to be smooth. Despite my 30+ years of MT experience the Z4M was inclined to cause me to look like I was 16 again since the CDV, in my case, got in the way of the clutch doing what I wanted when I wanted it. It doesn't help the notchiness of the shifts, but it does improve clutch modulation, and provides better control.

This is a "must do" mod in my book to fix a factory installed blemish on what is an otherwise great car.

[WhoU4]

Originally Posted by PatJags156

Anyone out there that regrets doing the CDV mod

No... I had mine replaced at an Indy shop who also installed my SSK, I thought there was a pleasant noticeable difference with how the clutch engaged after the swap. A bigger complaint for me is how light the accelerator feels but that's another story.

[inTgr8r]

I just deleted it & never looked back

[bdejong11129]

This is very interesting to me. I have been test driving a lot of Z4's lately ranging from 2005-2007 models. All manual(of cource) and all of the 3.0i. I cant say that I really noticed any issues with shifting.

Reading the information on zeckhausen it seems like there is no way I shouldnt have noticed it. Is this a very common replacement, so much so that all of the cars I have driven have had it done?

I did comment to the wife after the third one(Test Drive) that the clutch appeard to be very, how should I put it....soft. Just in terms of effort and that it always appeard to engage smoothly. Knowing this part explains that...

Can someone describe waht you mean by notchy?

Also, there was talk about premature wear on the clutch..I can reason out why this could happen, but is it actually happening and how soon?

[Caddyshk]

Originally Posted by Finnegan

No regrets. Zeckhausen addresses any warranty issues and the car is now easy to drive w/o it appearing like I'm an MT novice.

A "must do" mod in my book to fix a factory installed blemish on an otherwise great car.

How does Dave Z manage warranty issues?

To the OP - you're more likely to have clutch (wear) problems with the Lock Valve than without - unfortunately problems are likely to occur after warranty... The valve itself is designed to take shock out of the drivetrain so BMW can avoid warranty claims on related components by adding wear to the friction material...

[Caddyshk]

One more thing - if you drive it like it's a Toyota Mini Van you may not notice a difference...

[jbh]

I did it myself and could tell a difference. Clutch letoff is smoother and now predictable. No change in notchiness on shifts though.

[r4gs]

Originally Posted by bdejong11129

Can someone describe waht you mean by notchy?

my feelings of notchy equate with gear engagement, primarily gears 1 and 2. when shifting the gear lever from N to 1, 1 to 2, 3 to 2, or even 2 to 1 (rarely ever do so), marginally more effort's required to 'push' into gear as opposed with shifts in the upper gears (to 3, 4, 5 and 6).

[Ron Stygar]

Originally Posted by r4gs

my feelings of notchy equate with gear engagement, primarily gears 1 and 2. when shifting the gear lever from N to 1, 1 to 2, 3 to 2, or even 2 to 1 (rarely ever do so), marginally more effort's required to 'push' into gear as opposed with shifts in the upper gears (to 3, 4, 5 and 6).

Maybe you probably have air in the clutch bleed system.

[r4gs]

Originally Posted by Ron Stygar

Maybe you probably have air in the clutch bleed system.

i was under an impression that air bubbles in the clutch system would constitute a 'soft and sticky' clutch pedal rather than notchy engagement of lower gears? the mechanic at the transmission shop had me bleed the clutch thrice and everything feels stock as far as i'm aware after the cdv swap. only difference is the smoother engagement of gears upon clutch release.

[Ron Stygar]

Originally Posted by r4gs

i was under an impression that air bubbles in the clutch system would constitute a 'soft and sticky' clutch pedal rather than notchy engagement of lower gears? the mechanic at the transmission shop had me bleed the clutch thrice and everything feels stock as far as i'm aware after the cdv swap. only difference is the smoother engagement of gears upon clutch release.

Yes. The pedal goes down easier and farther down for release.

Did he remove the cylinder for the bleed?

[thekurgan]

CDV and the notchy engagement have nothing to do with each other. The only thing the CDV does is engage the clutch without the delay BMW implemented to reduce driveline shock. Since it's a one-way valve, stabbing the clutch is the same with or without the CDV.

[r4gs]

Originally Posted by Ron Stygar

Yes. The pedal goes down easier and farther down for release.

Did he remove the cylinder for the bleed?

ron, clutch was bled via the bleed screw on the cylinder itself. i'm trusting that it's sufficient? i honestly have not had any issues with my clutch pedal which might indicate the presence of air bubbles in the transmission lines, but u do have me a bit concerned with regards to my notchy gear lever engagement for the low gears.