CDV Delete - United Bimmer Community

**komodo** · 03-16-2006, 11:23 AM

I've recently heard quite a few people talking about a clutch delay valve delete.

Can someone explain to me what this is? Is it really beneficial? Any consequences?

Thanks.

**zeit00** · 03-16-2006, 11:56 AM

Quote:

Originally Posted by komodo

I've recently heard quite a few people talking about a clutch delay valve delete.

Can someone explain to me what this is? Is it really beneficial? Any consequences?

Thanks.

Clutch Delay Valve. It delays the actuation of the clutch helping relieve stress on the clutch/driveline. When you press the clutch a valve/spring allows the fluid to flow slowly.. Thus making the enangment smooth.

**bitcore** · 03-16-2006, 02:09 PM

Yes, but it does not make shifting gears smooth.
It slows down the responsiveness of the clutch, so you, the human, must compensate for that and realize that when you release the clutch, it dosn't release exactly as fast as you are lifting off the clutch pedal.
Engineers added it to prevent driveline shock from overly aggresive engagements (ex: dumping the clutch) but it winds up hampernig your ability to release the cluch when YOU know it needs engage.
so, if your a very experienced manual driver, you don't have as much control over when the clutch grabs, it's more noticeable during hard driving.

Google for it. theres a website selling gutted CDV's that explains it fully.

**zeit00** · 03-16-2006, 02:20 PM

Quote:

Originally Posted by bitcore

Yes, but it does not make shifting gears smooth.
It slows down the responsiveness of the clutch, so you, the human, must compensate for that and realize that when you release the clutch, it dosn't release exactly as fast as you are lifting off the clutch pedal.
Engineers added it to prevent driveline shock from overly aggresive engagements (ex: dumping the clutch) but it winds up hampernig your ability to release the cluch when YOU know it needs engage.
so, if your a very experienced manual driver, you don't have as much control over when the clutch grabs, it's more noticeable during hard driving.

Google for it. theres a website selling gutted CDV's that explains it fully.

For an agressive driver you are correct. For someone that does not drive too hard its pretty smooth. I agree though, it sucks big time.

**xsperf** · 03-16-2006, 05:55 PM

sorry guys i really dindt read previous responses, but basically BMW put it into the cars to have a smoother shifting(if you just drop the clutch, it wont exactly drup the clutch for you, it delays it a little bit)

**Tochenzo** · 03-16-2006, 07:00 PM

Quote:

Originally Posted by xsperf

sorry guys i really dindt read previous responses, but basically BMW put it into the cars to have a smoother shifting(if you just drop the clutch, it wont exactly drup the clutch for you, it delays it a little bit)

yup

i'm lookin into doing this as well when i get my new clutch/flywheel setup installed

**Phat Ham** · 03-17-2006, 03:20 PM

http://zeckhausen.com/CDV.htm

**Phat Ham** · 03-17-2006, 03:22 PM

Quote:

Originally Posted by bitcore

Google for it. theres a website selling gutted CDV's that explains it fully.

FWIW, you don't need to replace the CDV with a gutted one. You can just pull the CDV out and screw the hard line straight into the clutch slave cylinder.

**Rob** · 03-21-2006, 02:06 PM

I would have to disagree on the part about being experienced. I didn't even bother to install the CDV during the swap and I am fine with it.

As for deleting yours Harry, I am really questioning if it is down there. Kip went to the trouble of getting a lightweight flywheel installed, it's a possibility that he got the CDV removed at the same time. The only way to tell is to jack her up and look.

**komodo** · 03-21-2006, 02:17 PM

Quote:

Originally Posted by Rob

I would have to disagree on the part about being experienced. I didn't even bother to install the CDV during the swap and I am fine with it.

As for deleting yours Harry, I am really questioning if it is down there. Kip went to the trouble of getting a lightweight flywheel installed, it's a possibility that he got the CDV removed at the same time. The only way to tell is to jack her up and look.

True, but it was installed at the dealership, and I doubt they'd remove something like that unless he specifically asked for it... and honestly I doubt he knew what a CDV was.

**Rob** · 03-21-2006, 02:27 PM

Quote:

Originally Posted by komodo

True, but it was installed at the dealership, and I doubt they'd remove something like that unless he specifically asked for it... and honestly I doubt he knew what a CDV was.

True. We will just have to see for ourselves then.

**Avlany** · 03-21-2006, 02:49 PM

Nice. Thanks for the link Phat Ham. Awesome.

**barney** · 03-21-2006, 04:11 PM

Im going to have to do this now. I thought it was just the nature of the beast.

**xsperf** · 03-21-2006, 07:07 PM

its cant be vital, b/c BMWs are probably one of the very few cars that have them, all the other cars dont have them