Anyone do CDV (Clutch Delay Valve) Mod??

[thekurgan]

Originally Posted by Steveo58

Sure... It doesn't change the bite point or the actual feel at the shift knob, but it improves feel from your left foot on the clutch pedal. With the CDV in I thought it felt on the numb side at the pedal, but with it out you have more of a direct connection.

It also makes the shift from first to second much smoother and easier. It's really quite an easy mod to do, and there is no need to buy the aftermarket parts, just drill the existing one out or simply remove it. Hope this helps...

This makes no sense, the "lock valve" only acts one-way, when the clutch is engaging, hopefully, you're (yes, spelled this correctly!) already in second by then. The only thing the lock valve does is dampen the engagement, like dropping a needle on a record. It would have NO aid when selecting gears.

[tom @ eas]

The valve is a "straight through" design on the M3 (non-restrictive), there are zero performance benefits by removal.

[Time Lord]

my bite is extremly abrupt and hard to feel, will this mod help?

[tom @ eas]

Originally Posted by Giorgia

my bite is extremly abrupt and hard to feel, will this mod help?

The valve in the M3 is non-restrictive, removing it would be a waste of time.

[Time Lord]

Thank you

[Time Lord]

So what exactly is this MOD suppose to do? so confusing....

[tom @ eas]

Originally Posted by Giorgia

So what exactly is this MOD suppose to do? so confusing....

Nothing, it doesn't apply to M3.

The non-M models had a restrictive CDV which benefited by swapping over to the M3 piece (which is non-restrictive) or just removing it altogether. Anyone that tells you otherwise is basing judgement from placebo effect.

[The Nash]

Originally Posted by Giorgia

So what exactly is this MOD suppose to do? so confusing....

The clutch delay valve restricts brake fluid by action of the slave/master cylinder. This will slip the clutch a bit to allow marginal manual drivers to not stall out so easily from a start. It is only on non M platform cars. As stated above the M series cars do not use it, because the presumption is those driving an M would also know how to drive a manual correctly

[tom @ eas]

Here's some images to better illustrate what I'm referring to:

Location of the CDV on D/S:



Comparison of CDV orifice and line fitting:



There's zero restriction in comparison with the hard line. Hope this helps in the explanation.

[Time Lord]

lol thank you guys so much. this thread should be stickied and closed

[thekurgan]

Originally Posted by Habernash

The clutch delay valve restricts brake fluid by action of the slave/master cylinder. This will slip the clutch a bit to allow marginal manual drivers to not stall out so easily from a start. It is only on non M platform cars. As stated above the M series cars do not use it, because the presumption is those driving an M would also know how to drive a manual correctly

E8[5|6]M has one, and it was ugly.

[SanFranciscoM3]

I wanted to resurrect this thread. I have a 2008 E92 M3. I today removed the CDV and made a night and day improvement in the shifting. For anyone who has a question whether the E92 M3 had a CDV, mine definitely did.

[CamasM3e93]

Originally Posted by SanFranciscoM3

I wanted to resurrect this thread. I have a 2008 E92 M3. I today removed the CDV and made a night and day improvement in the shifting. For anyone who has a question whether the E92 M3 had a CDV, mine definitely did.

I 100% believe you feel an improvement but I also believe that tom @ eas knows his stuff (see his post above from years ago). Wondering if you had air in your system that the procedure resulted in purging, and that’s the reason for your observation. Do you know the last time your clutch hydraulics were flushed??? I’m always game for a 1 to 2 shift improvement.