*The Official E53 Manual Transmission Registry Thread*

[davintosh]

Yes, do it (the CDV delete.) It's an easy mod and makes a huge difference; I can't understand why BMW did it in the first place. It makes the clutch action very unnatural. With it gone, the clutch works as it should. The CDV isn't really a valve at all, it's just a flow restrictor. There is an orifice inside the CDV that creates a bottleneck for the flow of the hydraulic fluid. The diameter of the pipe is reduced considerably, which just slows movement of the clutch. I want to have the clutch moving when my foot moves the clutch pedal, not after.

Many people buy the doodad that replaces the CDV, but it really isn't necessary; one end of the CDV threads into the slave cylinder, and the hydraulic line fitting threads into the other. With the CDV out of the way, the hydraulic line fitting just threads into the body of the slave. I had a bit of a time getting things lined up properly, and ended up removing the slave to get it done, but that wasn't much of a problem at all.

[JCL]

Originally Posted by davintosh

Yes, do it (the CDV delete.) It's an easy mod and makes a huge difference; I can't understand why BMW did it in the first place. It makes the clutch action very unnatural. With it gone, the clutch works as it should. The CDV isn't really a valve at all, it's just a flow restrictor. There is an orifice inside the CDV that creates a bottleneck for the flow of the hydraulic fluid. The diameter of the pipe is reduced considerably, which just slows movement of the clutch. I want to have the clutch moving when my foot moves the clutch pedal, not after.

They did it to reduce driveline shock from people letting the clutch out too quickly. It doesn't change when the clutch moves, just how fast it moves, and thus the elapsed time until engagement.