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jpsimon jpsimon is offline
Junior Member
Posts: 111
Join Date: Feb 2008
Car: 335xi coupe
Default 06-19-2018, 07:21 AM

Bumping this thread.

Someone just responded to my post on another forum. He successfully solved this problem. This is definitely something I plan on doing:

Originally Posted by Remonster
I finally got around to deleting my 340i CDV after a thread on that other BMW forum. Long story short, Yes you can do it, yes you should do it, and it’s very easy.

If you disconnect the inlet line going into the clutch slave cylinder: you’ll see a silver metal restrictor plate with a TINY hole in it and a black rubber piece that holds that metal restrictor in place. The first guy who found this out said he drilled his to have a larger hole but I decided to just throw away the metal restrictor and rubber piece. The line has its own o-ring that seals it so you don’t need these other two pieces. Just throw them away, re-connect the line, flush your fluid and you’re done. The shifting experience is night and day better. Not only is it so much smoother and easier to avoid jerky shifts, the clutch feels like it holds a lot more torque. I was having slipping issues with my car (only power mod is MPPSK) when launching but that has gone away entirely.

So far, the couple people who have done this including myself took the clutch slave out of the car. I suspect you may be able to leave it in the car and use a pick to pull out the restrictor and rubber piece but it will not be easy. I don’t think anyone has tried that yet to be sure. Taking the slave out and putting it back is a little bit of a pain but done within an hour or two on a lift with proper tools. It’s just difficult to reach the top bolt if I remember correctly.
In response to me wondering if #13 in that part list was the CDV he says:

#13 is NOT the CDV. I had the same theory so I bought one to inspect and it has zero restriction in it. The only restriction is at the inlet to the slave and removing that gave me a heavier pedal with immediate response. I’m loving it. You may also want to get rid of the clutch pedal return spring while you’re trying to improve your shifting experience.

I asked him "Did you have a shift delay when going WOT and say shifting from 3rd to 4th? And if so, did this fix it? Back when I had my n54 there was a noticeable delay when shifting until the cdv was modified." and he says:

Yes and yes, the delay valve makes sure that the clutch engages later and slower than what you're trying to do with your left foot. Now, the clutch seems to follow your foot immediately and it just GRABS even when you're being aggressive with it.

BSM 340i xDrive (6MT, M-Sport, etc)
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