[jpsimon]

On my e92 335 there was a clutch delay valve which added some undesirable shift lag to the 6MT. You could buy a modified one to swap in to fix the issue.

Is there something like this on the 340?

[335xiRT1]

I've read that there is one but built into the clutch master cylinder.

[paul e]

I’m a bit confused...why would there be a valve designed to delay the clutch engagement to begin with?

[StuyMac]

Originally Posted by paul e

I’m a bit confused...why would there be a valve designed to delay the clutch engagement to begin with?

It's to dampen the clutch engagement to help protect the drivetrain.

[Mr. Tasty]

#13 looks vaguely like it could be a CDV.

Edit: After googling the part number, it looks like it is a CDV

[jpsimon]

Originally Posted by 335xiRT1

I've read that there is one but built into the clutch master cylinder.

Do you remember where you read it? When I google it, i find a thread on another forum where someone also says they've read it but I can't find the actual source of this information.


If it's true bmw built-in the CDV.... Would the CDV be built in to the master or slave cylinder? If it's in the slave, it looks like it could be modified pretty easily... or if #13 is indeed the CDV then we should be able to modify it no problem.

Here are some of the parts:

Here's #13:
https://www.ecstuning.com/b-genuine-...e/21526864478/

#14:
https://www.ecstuning.com/b-genuine-...t/21526795713/


(master cylinder... no picture)
https://www.ecstuning.com/b-genuine-...c/21526879477/

[335xiRT1]

It was in a forum. Not sure where it was a while ago when I was looking to get rid of it myself.
It does look like #13. It would be great if we could get rid of it or modify it.

[jpsimon]

It's a cheap part, one of us should just order #13 and take a gander

[paul e]

Originally Posted by StuyMac

It's to dampen the clutch engagement to help protect the drivetrain.

Thank you, appreciated.

[Mr. Tasty]

Originally Posted by jpsimon

It's a cheap part, one of us should just order #13 and take a gander

no need to order one, the part that I pointed out, is indeed a CDV.

[jpsimon]

Well I mean to order and actually modify.

[kern417]

usually you can just remove the line, use a pick to remove the reducer, reinstall and bleed the clutch.

i've noticed sometimes the car jerks pretty hard when i push in the clutch in 1st gear. i thought it was because there was no delay valve. i haven't noticed any issues with shifting or difficulty modulating the pedal.

[jpsimon]

I have no issues modulating the pedal, but there is noticeable shift lag a lot of the time which feels sort of similar to the e92 before i did the CDV delete. Couldn't hurt to see how it feels removing it. I may give this a whirl.

[eluded]

If your powershifting you feel a CDV somewhere.

[dab_of_oppo]

anybody delete/ modify the valve yet? You can really feel it shifting quickly

[jpsimon]

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.

[Remonster]

Originally Posted by jpsimon

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





In response to me wondering if #13 in that part list was the CDV he says:




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:

I didn't realize you were on this forum as well, Sticky over on that other forum doesn't like cross-linking between forums but all credit goes to TurboAra and this thread with useful pictures and information:

https://f30.bimmerpost.com/forums/sh....php?t=1486773

[jpsimon]

Good info in there, I will 100% be doing this.

[F32Fleet]

Originally Posted by jpsimon

On my e92 335 there was a clutch delay valve which added some undesirable shift lag to the 6MT. You could buy a modified one to swap in to fix the issue.

Is there something like this on the 340?

Not yet.

https://www.zeckhausen.com/catalog/index.php?cPath=6562

[jpsimon]

Originally Posted by F32Fleet

Not yet.

https://www.zeckhausen.com/catalog/index.php?cPath=6562

Read up a couple posts, it has been solved!