Clutch Delay Valve effects on launching

I took my car to the drag strip for the first time and had some serious issues with my clutch slipping. Previously, I've never had any issues with my clutch but I added about 4psi of boost which seemed to cause more harm than good. Normally, it would seem that my clutch is just worn out and couldn't handle either the extra power or extra heat involved. But I have less than 5000 miles on my spec stage 2+ so could it be possible that the stock cdv could be causing the issue? I find it hard to believe my clutch could have such a short lifespan. Especially when I'm on stock turbos atm. Any help would be appreciated.

Yeah, bypass it. It isn't going to help clutch life. <5000 miles something isn't right unless you spend several of those melting your clutch.

I'm putting the bms modified valve in this weekend and see if that helps. I just can't seem to figure out why that clutch failed so prematurely

You don't need the BMS modified valve unless you want your car to look like it has the cdv in it still; you can just bypass the whole thing.

Got it. Thanks for the info

I don't have a clutch pedal on my n54 but on my e39 you just remove the valve and plug the two ends together. $0 spent. Just make sure during the process you don't let too much fluid leak out or else you'll need to bleed the air out.

i actually have a log showing the CDV in action. i can post it if people want.

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Originally Posted by TwistedTuning

i actually have a log showing the CDV in action. i can post it if people want.

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Would be pretty cool to see!

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Originally Posted by BostonBeemah

Would be pretty cool to see!

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Below is a screenshot of a log i took a while ago when I was testing Flashable Launch control. This shows a 3400rpm two step launch from 1st gear into 2nd gear. The Area boxed in red shows where i grabbed 2nd gear and the CDV was doing its job essentially slipping the clutch regardless of being fully off the clutch and at full throttle. RPMS jumping up and down for a second cause the clutch was trying tograb but couldn't fully because of the CDV.

Not this isn't felt, which is why hard driving/shifting with a CDV kills so many clutches. because you think its completely released and grabbing, but its not.

Attachment 48136

Mine is coming out this weekend with my clutch and flywheel replacement. Bye Bye CDV

Quote:

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Originally Posted by TwistedTuning

Below is a screenshot of a log i took a while ago when I was testing Flashable Launch control. This shows a 3400rpm two step launch from 1st gear into 2nd gear. The Area boxed in red shows where i grabbed 2nd gear and the CDV was doing its job essentially slipping the clutch regardless of being fully off the clutch and at full throttle. RPMS jumping up and down for a second cause the clutch was trying tograb but couldn't fully because of the CDV.

Not this isn't felt, which is why hard driving/shifting with a CDV kills so many clutches. because you think its completely released and grabbing, but its not.

Attachment 48136

Mine is coming out this weekend with my clutch and flywheel replacement. Bye Bye CDV

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Rep for you. Looks like this is moving up my priority list.

I'm honestly surprised the CDV doesn't cause more slipping in these cars. Once a clutch begin to slip, it is far more likely to continue slipping on that run, and almost certain it won't stop unless you do something to let it grab, like release throttle. It is basically the same as having the clutch pedal pushed halfway in, although just momentarily, it limits the clamping power. That's bad slavery right there.

I removed mine, didn't notice much of a difference although the clutch is more direct. For feel alone I preferred it with the CDV in believe it or not, however being as my "is" clutch is already slipping, figured I wouldn't give it more opportunities.

Its probably less pronounced than other cars (like the AP2 S2000) because BMW also uses software to create an artificial delay.

On of the first things I did to my car but this just illustrates how big of a role it actually plays although it isn't really felt. Wish I guess other people deserve some before I can rep you again