What are pros and cons of removing CDV

Originally Posted by EverydayGetaway

Your logic is extremely flawed. The whole point of the dual mass flywheel and cdv is for smoother shifts...

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wrong. CDV is to prevent damage to the drivetrain from aggressive driving. here's a quote from the Zeckhausen website:

The Clutch Delay Valve (CDV) is a one-way restrictor installed by the factory between the clutch slave cylinder and clutch master cylinder, as shown in Figure 1. It "delays" the engagement of the clutch, much like old record players use a damped tone-arm to gently lower the needle onto the surface of a record.

Because of this valve, no matter how quickly you lift your foot off the clutch pedal, the clutch engages the flywheel at a constant (slow) rate. In theory, it can save the driveline from shock, were an inexperienced (or immature) driver to dump the clutch. But in practice, all it does is prematurely wear out the clutch and turn experienced drivers into people who, despite years of practice, cannot shift smoothly.

http://zeckhausen.com/cdv.htm

I don't know who these people are who "cannot shift smoothly". We left the CDV in place on my girlfriend's 330Ci, and we both shift as smooth as glass, in spite of the fact that we've both been driving manual transmissions for over 40 years. A clunky shift on these cars is either pilot error, or there's something mechanically wrong, such as a worn throw-out bearing. Our 103,000 miles with the CDV in place show that the CDV doesn't cause rough shifting.

Edit: And the original clutch is still in the car, so it's not exactly worn out prematurely. By the way, I'm a (relatively) conservative driver, but she's not - she drives like a bat out of hell. I have to work at it to keep up in my 545.

Originally Posted by webster

wrong. CDV is to prevent damage to the drivetrain from aggressive driving. here's a quote from the Zeckhausen website:



http://zeckhausen.com/cdv.htm

And how am I wrong? It prevents sudden clutch releases, aka, smoother shifting... It's like all modern BMW Inovations that assume the driver of the car is a nitwit, sadly they're probably right about most drivers.

If you're going to call someone out, have a logical response first.

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Originally Posted by Wolrab

I don't know who these people are who "cannot shift smoothly". We left the CDV in place on my girlfriend's 330Ci, and we both shift as smooth as glass, in spite of the fact that we've both been driving manual transmissions for over 40 years. A clunky shift on these cars is either pilot error, or there's something mechanically wrong, such as a worn throw-out bearing. Our 103,000 miles with the CDV in place show that the CDV doesn't cause rough shifting.

Edit: And the original clutch is still in the car, so it's not exactly worn out prematurely. By the way, I'm a (relatively) conservative driver, but she's not - she drives like a bat out of hell. I have to work at it to keep up in my 545.

Shifting speed/techique is a big part of this. I shift too fast apparently. CDV valve was acting like it was a shift gate. Removed it and don't have that problem anymore. I drove it 10k+ miles before I finally removed it. Problem gone.

Originally Posted by EverydayGetaway

And how am I wrong? It prevents sudden clutch releases, aka, smoother shifting... It's like all modern BMW Inovations that assume the driver of the car is a nitwit, sadly they're probably right about most drivers.

If you're going to call someone out, have a logical response first.

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You are wrong because he was right. You are now shaving hairs.

Originally Posted by alkemyst

You are wrong because he was right. You are now shaving hairs.

Again, how am I wrong? CDV DELAYS THE CLUTCH. It's so that you don't drop the clutch and chirp your tires (SMOOTHER SHIFTING). I didn't say he was wrong about it preventing drivetrain wear, but it also allows smoother shifting for those who fail at driving a clutch, so please kindly eatadik

Originally Posted by empirem3

Well the downside is that you can smoke your fly wheel/clutch in no time if you have a few bad shifts.

but the problem may be else where

Only if you're a dumb f****er. People have been driving without CDVs for a long time. God knows why BMW thought it was a good thing to intervene between a driver and their foot in the first place. Its a lot more flexible than a ferkin CDV. Makes no sense to me at all. I think they did it to mask a crappy diaphragm design.

Originally Posted by sharkey62

Hi
I am new to BMW's. I have read a few posts on here when I have been searching for information on clutch delay valves. I have a 2001 320i and cannot get a smooth gear change. I have been driving for 30 years so feel like a learner when the car jerks on gear changes. I have read that most people have removed the valve but just wondered if there were any negatives by doing this. Would it solve one problem and create another.
Any info would be most appreciated.

Just do it. If you can use a clutch then there's no problem. It will be similar to the vid below

Originally Posted by Wolrab

I don't know who these people are who "cannot shift smoothly". We left the CDV in place on my girlfriend's 330Ci, and we both shift as smooth as glass, in spite of the fact that we've both been driving manual transmissions for over 40 years. A clunky shift on these cars is either pilot error, or there's something mechanically wrong, such as a worn throw-out bearing. Our 103,000 miles with the CDV in place show that the CDV doesn't cause rough shifting.

Congratulations! You've been enjoying smooth shifts for all those miles in your 330Ci coupe because you never had a CDV. Not installed on this model.

If you had the CDV you'd be jerking with the best of them.

See the list: http://zeckhausen.com/cdv.htm

Originally Posted by Stinger9

Congratulations! You've been enjoying smooth shifts for all those miles in your 330Ci coupe because you never had a CDV. Not installed on this model.

If you had the CDV you'd be jerking with the best of them.

See the list: http://zeckhausen.com/cdv.htm

BRILLAINT!!! Can't wait to read the comeback.

Originally Posted by Stinger9

Congratulations! You've been enjoying smooth shifts for all those miles in your 330Ci coupe because you never had a CDV. Not installed on this model.

If you had the CDV you'd be jerking with the best of them.

See the list: http://zeckhausen.com/cdv.htm

Originally Posted by RayPooley

BRILLAINT!!! Can't wait to read the comeback.

It's just in a different in-line location on that model.

http://realoem.com/bmw/showparts.do?...94&hg=21&fg=10

Part # 15

Originally Posted by pleiades

It's just in a different in-line location on that model.

http://realoem.com/bmw/showparts.do?...94&hg=21&fg=10

Part # 15

Just have to know how to do your research. Use your same cherished realoem and plug in the part #15 number------21526755892

This will give you all the vehicles that the part applies to. And you'll see it was on the vert, but never the 330Ci coupe.

My witness: http://realoem.com/bmw/partxref.do?part=21526755892

You're more than welcome to stop by again some time!

Originally Posted by Stinger9

Just have to know how to do your research. Use your same cherished realoem and plug in the part #15 number------21526755892

This will give you all the vehicles that the part applies to. And you'll see it was on the vert, but never the 330Ci coupe.

My witness: http://realoem.com/bmw/partxref.do?part=21526755892

You're more than welcome to stop by again some time!

Well shut my mouth, I learned something, just not what I expected. Now I have to wonder, why not the coupe? Different clutch altogether?

I think the coupe is just designed with more spirited driving in mind and things are slanted in that direction. Comes standard with sport suspension, etc.
The rest of the breed is more of a compromise with lux smooth driving.

I'm betting the clutch and pressure plate are the same.

Even normal daily driving you'll notice the difference. I always fell like a jackass jerking the car around. Finally removed it and wow. Why did i wait so long.
Some say you can do more damage to the drive train with it removed, other say it causes trouble.

has anyone ever damaged anything drive train related after removing it ? I haven't heard of anything.

There were two things that disappointing me when i got my 330. The shifting was.. meh.. and the throttle response was slow. Removing the cdv fixed most of the shifting issues. Maybe a chip will fix the throttle response.

Originally Posted by Stinger9

Just have to know how to do your research. Use your same cherished realoem and plug in the part #15 number------21526755892

This will give you all the vehicles that the part applies to. And you'll see it was on the vert, but never the 330Ci coupe.

My witness: http://realoem.com/bmw/partxref.do?part=21526755892

You're more than welcome to stop by again some time!

well it was actually on the 330ci...but listed for the european models. which i always found interesting that BMWNA didn't fit them.
http://realoem.com/bmw/partxref.do?p...=on&series=E46

At this point I think we've extended ourselves into the rarefied and arcane world of what minutiae options did BMW fiddle with in various markets around the world. I'm not up for joining the nerd club, so I'll politely disengage thank you.
My concern is only with the USA.