Clutch delay valve.

**Capt. Slow** · 11-20-2012 08:05 AM

So i feel like the car must have one cause the car jerks every time I shift, and I've been driving manuals all my life, never had problems like this. I remember the feeling from my friends 335i 6MT. Is there a solution for this? i.e.. Aftermarket replacement, rebuilding the stock? I know BMW guys had a solution for this, just don't know what they did.

**Sjones630** · 11-20-2012 08:15 AM

BMW mt's have a clutch delay valve in the hydraulic line. It is intended to moderate the speed of clutch engagement when you dump the clutch. Many owners simply removed the valve. Others, fearing warrantee issues if the missing valve was spotted by BMW techs, bought modified valves that had been "gutted" to make them nonfunctional, but appearing stock. The BMW one was located where the hydraulic line attached to the clutch slave cyl. I don't know if the S4 has one, but it would show up on the parts diagram of an OEM parts supplier.

**S4charged** · 11-20-2012 08:59 AM

My BMW 335i 6MT had a CDV.. removed it.. what a difference it was... after that no more jerky shifts from 1-2-3

Can't comment on the S4 though, not sure if it has one.. shifts have to be pretty much perfect to not jerk 1-2, or ride the clutch.

**IceAero** · 11-20-2012 09:01 AM

Originally Posted by Capt. Slow

So i feel like the car must have one cause the car jerks every time I shift, and I've been driving manuals all my life, never had problems like this. I remember the feeling from my friends 335i 6MT. Is there a solution for this? i.e.. Aftermarket replacement, rebuilding the stock? I know BMW guys had a solution for this, just don't know what they did.

I have learned to combat this with a little more throttle when letting the clutch out, and doing that just a tad slower to make sure I catch the engine speed correctly because the revs drop a bit slow (apparently this has something to do with emission reqs. post 2004...) and 1st is short. It's smooth, but I know my clutch is working harder.

Still, it makes me wonder as well (full disclosure, this is my first manual car with AWD). I've come across the CDV posts in BMW forums and it would be interesting to know if we had something similar.

**ENV²** · 11-20-2012 09:57 AM

This car takes finesse. I felt this was a problem when I first got my car as well. Now I am used to it. It takes modulation of throttle, clutch, and paying some attention to shift points.

Finesse, young grasshopper.

**gringoloco2000** · 11-20-2012 10:40 AM

I love this car, but it shifts like dirt compared to my old MKIV .:R32. Even with the JHM shifter it is still light years away from my R32.

**Capt. Slow** · 11-20-2012 11:05 AM

I miss the 6MT from my STi, nothing out there beats the feel and reliability of that tranny!! Oh well guess I'll have to get used to it then.

**Wilbur** · 11-20-2012 01:15 PM

Originally Posted by ENV²

This car takes finesse. I felt this was a problem when I first got my car as well. Now I am used to it. It takes modulation of throttle, clutch, and paying some attention to shift points.

Finesse, young grasshopper.

Exactly. Every MT/clutch is different. Some BMW guys swear the CDV mod is great while others say it does nothing. I'm with this guy........patience.

**S4charged** · 11-20-2012 04:22 PM

Originally Posted by Wilbur

Exactly. Every MT/clutch is different. Some BMW guys swear the CDV mod is great while others say it does nothing. I'm with this guy........patience.

Whoever says the CDV mod does nothing is crazy!!!! Night and day difference.

But yeah I find that i do have to slowly release the clutch when shifting to reduce or remove jerkiness..

**Dr GP** · 11-20-2012 05:50 PM

I agree with IceAero. I tried different aproaches in letting the clutch out with not much positive result. The solution is to use MORE throttle, not a slower clutch release. Try it . You'll see a difference.

**ENV²** · 11-20-2012 06:43 PM

Originally Posted by gringoloco2000

I love this car, but it shifts like dirt compared to my old MKIV .:R32. Even with the JHM shifter it is still light years away from my R32.

Eurocode STS will do wonders for the car + Alu Kreuz takes away that jerky drivetrain slop. Get them and thank me.

**mattchat** · 11-20-2012 08:50 PM

I removed the CDV on my Accord 6MT, it made a huge difference. Haven't had any issues with the B8.5, as much as the world raves about honda manuals, they're nothing compared to german. I agree it could use improvement but its soooo much better than the accord. Especially after upping the power, the clutch was getting tired. Removing the CDV helped.

**jdwk** · 11-20-2012 09:02 PM

I don't have a delay valve in my other MT cars, and I didn't notice anything in the week I had my S4 that would lead me to believe there was one in the S4. My friend's Exige had one and it would literally slip the clutch between shifts, which was an awful feeling. We removed it immediately and all was well.

Whether driving in traffic or aggressively on the track, the S4 never jerked nor did it ever feel like it was slipping. I tried taking it easy on the brand new tranny, and it is definitely the easiest of my cars to keep my wife's head from bouncing against her headrest.

It almost sounds like the guys who are having trouble are coming from cars that have a CDV and are used to just stepping off the clutch instead of letting it out. The CDV lets the clutch out progressively for you but limits the speed at which you can change gears. I think it'll just take some people practice to learn how to rev match and let the pedal out smoothly.

**Draxus** · 11-20-2012 09:16 PM

So... how about you 6MT guys start looking? Follow the clutch line. It looks like a little filter on it.

**jdwk** · 11-21-2012 12:28 AM

Current ETA is Dec 15th. I can look then, but I am sure somebody has to know this already.

**Wilbur** · 11-21-2012 09:07 AM

Originally Posted by S4charged

Whoever says the CDV mod does nothing is crazy!!!! Night and day difference.

But yeah I find that i do have to slowly release the clutch when shifting to reduce or remove jerkiness..

Why does the CDV exist then?

**Wilbur** · 11-21-2012 09:33 AM

Originally Posted by S4charged

Whoever says the CDV mod does nothing is crazy!!!! Night and day difference.

But yeah I find that i do have to slowly release the clutch when shifting to reduce or remove jerkiness..

Re-BMW CDV comments....Automobile mag and C&D specifically mention how nice BMW clutch is...........with CDV. It must be there for a reason?

**ENV²** · 11-21-2012 11:02 AM

Originally Posted by mattchat

I removed the CDV on my Accord 6MT, it made a huge difference. Haven't had any issues with the B8.5, as much as the world raves about honda manuals, they're nothing compared to german (except for the S2000 gearbox). I agree it could use improvement but its soooo much better than the accord. Especially after upping the power, the clutch was getting tired. Removing the CDV helped.

Fixed for you

**jdwk** · 11-21-2012 11:06 AM

It is there because it helps drivers engage the clutch smoothly. It is kind of like a mechanical launch control.

If you aren't used to it, it is incredibly frustrating. Anyone who can modulate pressure with their left foot and can grasp the concept of rev matching would probably prefer it removed.

**IceAero** · 11-21-2012 12:11 PM

Also, if we're going to complain a bit about the manual transmission. I'd MUCH rather talk about how 6th gear isn't tall enough. The 2013 DSG turns fewer RPMs in 6th than the manual does in 6th, and it has a 7th gear to work with!

I simply don't understand why they put 6th so close to 5th =\

**NetMagi** · 11-21-2012 07:05 PM

I had a thread on the "jerky" transmission as well. . . I eventually learned to finesse it and got consistently smooth, but gosh darn if the 6-spd in my FR-S isn't twice as nice the 6-spd in the S4. Driving the S4 after the FR-S I feel like the stick is 2 feet tall with no "feel" in the gates. Now if the FR-S only had some torque once I finished each gear change :P

-Rich H.

**Thomas@TAI-VW** · 11-21-2012 07:50 PM

I agree with everyone here,this is one of the oddest feeling clutches at first,you have to drive it a bit aggressively and it feels fine,when I try to baby it, it has a lot of "springiness" in the engagement. I honestly think it is the crappy dual mass flywheel design,if you have ever seen a dual mass flywheel it is like a big "spring" and allows easy engagement of the clutch,but also gives a rubber-bandy feel. I am totally used to it now and it drives great,however if you baby it it will feel wierd..
There is also a odd thing on these cars,when you press in the clutch and start to let it out the engine will "rev" a little automatically so the engine does not stall out,I think it is designed to do this to help with the drag of the supercharger and I have seen the revs come up more than once so i know it is "there".

**mattchat** · 11-23-2012 12:26 AM

Originally Posted by mattchat

I removed the CDV on my Accord 6MT, it made a huge difference. Haven't had any issues with the B8.5, as much as the world raves about honda manuals, they're nothing compared to german (except for the S2000 gearbox). I agree it could use improvement but its soooo much better than the accord. Especially after upping the power, the clutch was getting tired. Removing the CDV helped.

Originally Posted by ENV²

Fixed for you

TRUE TRUE, the S2000 doesn't have a CDV....thats why!

**Wilbur** · 11-23-2012 07:04 AM

Originally Posted by Thomas@TAI-VW

I agree with everyone here,this is one of the oddest feeling clutches at first,you have to drive it a bit aggressively and it feels fine,when I try to baby it, it has a lot of "springiness" in the engagement. I honestly think it is the crappy dual mass flywheel design,if you have ever seen a dual mass flywheel it is like a big "spring" and allows easy engagement of the clutch,but also gives a rubber-bandy feel. I am totally used to it now and it drives great,however if you baby it it will feel wierd..
There is also a odd thing on these cars,when you press in the clutch and start to let it out the engine will "rev" a little automatically so the engine does not stall out,I think it is designed to do this to help with the drag of the supercharger and I have seen the revs come up more than once so i know it is "there".

Isnt that just the ECU trying to stabilize RPM ? I've driven manual for 36 years and rev match every downshift without issue.. CDV is something new to me. I'd have more fun without it?

**jdwk** · 11-23-2012 09:52 PM

Originally Posted by IceAero

Also, if we're going to complain a bit about the manual transmission. I'd MUCH rather talk about how 6th gear isn't tall enough. The 2013 DSG turns fewer RPMs in 6th than the manual does in 6th, and it has a 7th gear to work with!

I simply don't understand why they put 6th so close to 5th =\

Yeah that is strange short but it is smooth at highway speeds and still gets good gas mileage and you don't have to downshift to pass.

**dparm** · 11-23-2012 10:02 PM

Originally Posted by mattchat

Originally Posted by mattchat

I removed the CDV on my Accord 6MT, it made a huge difference. Haven't had any issues with the B8.5, as much as the world raves about honda manuals, they're nothing compared to german (except for the S2000 gearbox). I agree it could use improvement but its soooo much better than the accord. Especially after upping the power, the clutch was getting tired. Removing the CDV helped.

TRUE TRUE, the S2000 doesn't have a CDV....thats why!

Yes it did.

Also, my old Honda B-series transmission still remains one of the best to drive.

**jdwk** · 11-23-2012 10:06 PM

I drove the RX-8 and S2000 back to back and I actually liked the Mazda a little better, but nothing I've driven has come close to those two.

**NetMagi** · 11-25-2012 11:33 AM

Originally Posted by jdwk

I drove the RX-8 and S2000 back to back and I actually liked the Mazda a little better, but nothing I've driven has come close to those two.

Test drive an fr-s 6mt (if you can find one). :)

-Rich H.

**IceAero** · 11-26-2012 02:01 PM

So this is somewhat related, does anyone notice that the engine/shifts feels a little different with the ESC set to 'sport' ? It might be my mind playing tricks on me, I swear the timing of the revs falling is somehow different.

**mattchat** · 11-26-2012 11:35 PM

AP2 does, AP1 did not. Used a different fly wheel as well. When they increased the displacement to 2.2 and had a bit more power they made some minor gear box changes.

Originally Posted by dparm

Yes it did.

Also, my old Honda B-series transmission still remains one of the best to drive.

**ECS Tuning-Audi** · 11-27-2012 09:15 AM

On the topic of jerky shifting - The Audi clutch release point is very high. This is nice because you don't have to depress the pedal a lot to release the clutch. On a different note if you're not used to this it can be difficult to match the ratio at which you press the gas pedal and release the clutch (often lots of slipping or over revving occurs). This is where the jerkiness comes in. For the smoothest shifts possible I've learned to hardly press the clutch pedal. Just a quick controlled dab if you will is all it takes. Otherwise you will be finessing every shift.

There's definitely a learning curve, I hope this helps!

Jason

**ryank382** · 11-28-2012 10:03 PM

Just read up on everything everybody said and was also wondering if there is a cdv. As for the jerky shifts, try keeping the clutch in for a second longer for the rpms to drop and then engage. This help to get rid of the jerkiness rather than playing with the throttle and riding the clutch. Especially in 1st-2nd if u just wait for the rpms to drop just a little more u will see what I'm talking about. Hope this helps

**jdwk** · 11-30-2012 02:15 AM

Originally Posted by NetMagi

Test drive an fr-s 6mt (if you can find one). :)

-Rich H.

I really really want to, and was hoping to wait for a turbocharged version, but Toyobaru keeps denying it will exist. I suppose the shifter can still amaze me even if the sub 200hp motor doesn't.

**Capt. Slow** · 01-14-2013 08:27 PM

Originally Posted by Draxus

So... how about you 6MT guys start looking? Follow the clutch line. It looks like a little filter on it.

So... Anybody do this?

**Mancha** · 01-14-2013 10:11 PM

Interested as well.

**dogbert** · 01-15-2013 06:28 AM

Gah, this was/is my biggest concern of the S4! I'm about to place an order for an S4 manual and coming from an STI, the clutch/shifter feels like i'm driving an 18 wheeler (exaggerating of course). On the STI you could *feel* every millimeter of the clutch and engagement, rev matching, heel/toe shifting was easy and feedback was immediate. I test drove the S4 for almost 20 minutes and chalked it up to the fact that i just wasn't used to it. Is the manual that far off from other "sporty" cars?

**ryank382** · 01-15-2013 09:28 AM

Someone find out already lol

**ECS Tuning-Audi** · 01-15-2013 10:45 AM

Our parts data base doesn't mention anything about a valve BUT check out the picture below this is part of the clutch line assembly which looks to have some valves in it circled in red.

Jason

**vwong** · 01-15-2013 01:37 PM

Originally Posted by ECS Tuning-Audi

Our parts data base doesn't mention anything about a valve BUT check out the picture below this is part of the clutch line assembly which looks to have some valves in it circled in red.

Jason

Jason, what is #16 in this illustration?