BMW Garage BMW Meets Register Search Today's Posts Mark Forums Read
BMW M2 Forum > BMW M2 Competition Model > CDV Removal/Replacement "Easier" Option

Post Reply
 
Thread Tools Search this Thread
      08-21-2020, 02:19 PM   #67
VisualEcho
Banned
VisualEcho's Avatar
United_States
6626
Rep
4,145
Posts

Drives: '18 M2 6MT
Join Date: Sep 2019
Location: Missouri

iTrader: (1)

Garage List
2018 BMW M2  [10.00]
Quote:
Originally Posted by Daytona_550 View Post
The best way that I can explain it is that, with the unrestricted slave cylinder, the clutch engagement follows the action of your foot at a linear rate. With the CDV, the clutch action lags behind your foot, and not in a consistent or predictable way.
There have been many moments in the M where I tried to drive the car aggressively and instead of lurching forward there was a noticeable pause before the power came on, a "dead spot" like (forgive me) vapor-lock on the old carb cars. At first I thought it was just me giving the car too much clutch and not enough gas, until I got back in my Lotus after driving the M for a while and under no circumstance did the car do that. And not only that, the engagement is just so sure-footed in the Lotus, I mean, it's so hard to explain. It's like the M is thinking about everything I do, trying to sort it out.

I have often wondered if this is the CDV, and if it is, it's damn worth replacing to get rid of it.
Appreciate 0
      08-31-2020, 09:32 AM   #68
jkoral
Lieutenant Colonel
United_States
1016
Rep
1,960
Posts

Drives: 2017 M2 LBB 6MT
Join Date: Oct 2007
Location: MA

iTrader: (7)

So everyone's pedal has firmed up and no regrets? I've removed the CDV in my last 4 BMWs but I've yet to do it to the M2. Planning on having a shop do the job later this month.
Appreciate 0
      08-31-2020, 10:06 AM   #69
j23
Lieutenant
United_States
655
Rep
501
Posts

Drives: 2021 M2C
Join Date: Aug 2020
Location: IL

iTrader: (0)

Quote:
Originally Posted by Montaver View Post
This strikes me as one of those placebo mods, and reading between the lines doesn't actually improve anything. The stock clutch feels very consistent to me, if a little long at the very top.
I would have to mostly agree with you.

I had the UCP paired with CDV delete on my e46 M3. It felt good because it was different. However, I wouldn't do it again. The stock CDV is there to engage the drivetrain without introducing shock. And while this can be annoying, I only found it so in the beginning. Once I got used to it, I didn't think twice about it. I've driven manual cars for over 20 years and I personally think that the CDV is a nice precaution to have. I believe it will prolong the life of the flywheel even amongst experienced drivers. A properly functioning valve should be undetectable under normal driving and only showing up when you get abusive with the clutch. When I give my best to shift smoothly and properly, I can't even tell that a CDV is there. It's my understanding that CDV allows the dual mass flywheel a soft engagement to prevent the flywheel from bottoming out and damaging the ears that press against the springs.
Appreciate 0
      08-31-2020, 10:15 AM   #70
CTSean
First Lieutenant
323
Rep
392
Posts

Drives: LCI BSM MT M2
Join Date: Dec 2018
Location: CT

iTrader: (1)

Quote:
Originally Posted by j23 View Post
I would have to mostly agree with you.

I had the UCP paired with CDV delete on my e46 M3. It felt good because it was different. However, I wouldn't do it again. The stock CDV is there to engage the drivetrain without introducing shock. And while this can be annoying, I only found it so in the beginning. Once I got used to it, I didn't think twice about it. I've driven manual cars for over 20 years and I personally think that the CDV is a nice precaution to have. I believe it will prolong the life of the flywheel even amongst experienced drivers. A properly functioning valve should be undetectable under normal driving and only showing up when you get abusive with the clutch. When I give my best to shift smoothly and properly, I can't even tell that a CDV is there. It's my understanding that CDV allows the dual mass flywheel a soft engagement to prevent the flywheel from bottoming out and damaging the ears that press against the springs.
As a manual driver of 20+ years, the removal of the CDV from both my E36 and E46 (both of which were driven over 150K miles on their original clutches) was immediately noticeable and an instant improvement.

I can accomodate the restrictor in the clutch line by slowing my leg movement so the fluid isn't trying to move too fast but why would I want to do that?
Appreciate 0
      08-31-2020, 10:40 AM   #71
j23
Lieutenant
United_States
655
Rep
501
Posts

Drives: 2021 M2C
Join Date: Aug 2020
Location: IL

iTrader: (0)

Quote:
Originally Posted by CTSean View Post
Quote:
Originally Posted by j23 View Post
I would have to mostly agree with you.

I had the UCP paired with CDV delete on my e46 M3. It felt good because it was different. However, I wouldn't do it again. The stock CDV is there to engage the drivetrain without introducing shock. And while this can be annoying, I only found it so in the beginning. Once I got used to it, I didn't think twice about it. I've driven manual cars for over 20 years and I personally think that the CDV is a nice precaution to have. I believe it will prolong the life of the flywheel even amongst experienced drivers. A properly functioning valve should be undetectable under normal driving and only showing up when you get abusive with the clutch. When I give my best to shift smoothly and properly, I can't even tell that a CDV is there. It's my understanding that CDV allows the dual mass flywheel a soft engagement to prevent the flywheel from bottoming out and damaging the ears that press against the springs.
As a manual driver of 20+ years, the removal of the CDV from both my E36 and E46 (both of which were driven over 150K miles on their original clutches) was immediately noticeable and an instant improvement.

I can accomodate the restrictor in the clutch line by slowing my leg movement so the fluid isn't trying to move too fast but why would I want to do that?
Different strokes. I personally never had a problem releasing the clutch quickly and smoothly with the CDV. It's just a different dynamic. Some don't like it. Others don't mind it one bit. My point had more to do with the fact that it's there for a reason. I never said that removing it will actually lead to premature wear.
Appreciate 0
      10-07-2020, 04:56 AM   #72
cpxchewy
Monkey
119
Rep
241
Posts

Drives: 2020 M2C
Join Date: Aug 2014
Location: California

iTrader: (1)

I've been reading this thread and I think the CDV is the issue here. Can anyone confirm?
In S+ mode randomly when I shift from 1st to 2nd the car would jerk like crazy and you can see the rev bounce between 200-300 rpm or so. I've never had this problem in other gears and in efficient mode and just chocked up to driver error.

If this is a CDV issue then I'm definitely gonna do this..
Appreciate 0
      10-07-2020, 08:04 AM   #73
nearwater4me
Colonel
1910
Rep
2,127
Posts

Drives: '22 G82 Base
Join Date: Sep 2019
Location: GA

iTrader: (1)

Quote:
Originally Posted by cpxchewy View Post
I've been reading this thread and I think the CDV is the issue here. Can anyone confirm?
In S+ mode randomly when I shift from 1st to 2nd the car would jerk like crazy and you can see the rev bounce between 200-300 rpm or so. I've never had this problem in other gears and in efficient mode and just chocked up to driver error.

If this is a CDV issue then I'm definitely gonna do this..
I think it’s a combination of the CDV + throttle mapping.
I drive in S+ mode most of the time once the engine warms up, and this has been the annoyance since day 1.
I’ve gotten better at modulating (read: slipping) the clutch, but it gets jerky again once I get careless.
Appreciate 0
      10-07-2020, 08:23 AM   #74
thebiglubinsky
Private First Class
39
Rep
110
Posts

Drives: 3
Join Date: Jul 2009
Location: S FL

iTrader: (1)

Would doing this mod void your Powertrain warranty???
Appreciate 0
      10-07-2020, 08:37 AM   #75
Poochie
Luxury at the redline :)
Poochie's Avatar
United_States
9099
Rep
7,563
Posts

Drives: 2016 M2
Join Date: Aug 2012
Location: NYC

iTrader: (3)

Quote:
Originally Posted by thebiglubinsky View Post
Would doing this mod void your Powertrain warranty???
It would not, just never mention this mod to them and should any issues arise, just say it came that way🤷🏻

You might not get into Heaven because of your dishonesty or omission but your warranty will remain intact, here on earth...
Appreciate 2
      10-07-2020, 08:55 AM   #76
Kleinacus
Captain
United_States
671
Rep
873
Posts

Drives: M2C 6MT Build Week 33
Join Date: Jan 2009
Location: Philly Suburbs

iTrader: (1)

So I read this as slave cylinder swap and UCP are mandatory for any m2 comp tuned. SSK is an option after that. I plan on getting the cylinder and UCP done first thing in the spring and then I'll decide on SSK. Now I just need to find the damn post where Thescout13 lists out his perfect UCP settings. I failed on my first search attempt as UCP is referenced a ton on this forum and he posts a lot. I'll give it another go later before I bug him.
__________________
2019 m2c 6MT C33/29U/MDOE/4MC/ZEC/Z4G/Z09/AA mid/Remus Axle-back Race/Carbahn Stage 1
2014 B8.5 s4 6MT Monsoon Gray Metallic/Black Optics/RS Grille/GIAC Stage 1/AWE Touring Exhaust & S-Flo Intake/H&R Sway Bars/Bilstein PSS10
Appreciate 0
      10-07-2020, 10:10 AM   #77
j23
Lieutenant
United_States
655
Rep
501
Posts

Drives: 2021 M2C
Join Date: Aug 2020
Location: IL

iTrader: (0)

I'm definitely in the minority here, but I didn't like my AS SSK. I had it in both 20% and 30% reduction on prior BMW's paired with CDV delete. I loved them initially because shifting felt very precise and the throws were shortened. However, over time, I realized that the shifter was more finicky than I wanted. It required a lot more effort to get the shifts crisp. Colder weather is when the shifter really struggled and felt a lot more notchy than a stock shifter. Miss-shifts were more common, as well.

The stock shifter on the M2C gets a lot of heat from the SSK crowd, but it's actually an amazing piece. Now I understand why it works and feels the way it does. The little bit of slop is built-in there for a reason. Missing a shift is virtually impossible. It works great and never locks up on me like downshifts with the AS SSK did, especially during hard cornering at autocross.
Appreciate 0
      10-07-2020, 10:39 AM   #78
Thescout13
Brigadier General
Thescout13's Avatar
United_States
4944
Rep
4,976
Posts

Drives: '20 F80 M3CS, %E2%80%9818 GT3
Join Date: Nov 2013
Location: California

iTrader: (0)

Quote:
Originally Posted by thebiglubinsky View Post
Would doing this mod void your Powertrain warranty???
Idk how they would find out????????

Unless they took apart every little piece of the clutch line, and they are comparing each component to images, which they don't/won't know to do.
__________________
Wife's Car: 2020 X4M Competition, Alpine White on Black Alcantara and Biege
Current Car: 2018 F80 M3CS, SMB, DCT, ZEC, MPE
Recently Departed: 2020 F87 M2C, LBB, ZEC, 6MT (Euro Delivery Aug. 29, 2019, totaled by an idiot in a Camry who then ran from the scene)
Wife's Prior Car: 2018 F80 M3, Yas Marina Blue, DCT, Black 19s, Carbon Structure Anthracite Cloth/Leather Combination, Driving Assistance Package (Euro Delivery Oct. 9, 2017)
Appreciate 0
      10-07-2020, 10:40 AM   #79
Thescout13
Brigadier General
Thescout13's Avatar
United_States
4944
Rep
4,976
Posts

Drives: '20 F80 M3CS, %E2%80%9818 GT3
Join Date: Nov 2013
Location: California

iTrader: (0)

Quote:
Originally Posted by Kleinacus View Post
So I read this as slave cylinder swap and UCP are mandatory for any m2 comp tuned. SSK is an option after that. I plan on getting the cylinder and UCP done first thing in the spring and then I'll decide on SSK. Now I just need to find the damn post where Thescout13 lists out his perfect UCP settings. I failed on my first search attempt as UCP is referenced a ton on this forum and he posts a lot. I'll give it another go later before I bug him.
Stock setting on the UCP. It's like butter now.
__________________
Wife's Car: 2020 X4M Competition, Alpine White on Black Alcantara and Biege
Current Car: 2018 F80 M3CS, SMB, DCT, ZEC, MPE
Recently Departed: 2020 F87 M2C, LBB, ZEC, 6MT (Euro Delivery Aug. 29, 2019, totaled by an idiot in a Camry who then ran from the scene)
Wife's Prior Car: 2018 F80 M3, Yas Marina Blue, DCT, Black 19s, Carbon Structure Anthracite Cloth/Leather Combination, Driving Assistance Package (Euro Delivery Oct. 9, 2017)
Appreciate 2
      10-07-2020, 11:22 AM   #80
boss2k
Colonel
1039
Rep
2,756
Posts

Drives: 2021 M2C
Join Date: Jan 2010
Location: Atlanta

iTrader: (2)

Quote:
Originally Posted by Thescout13 View Post
Stock setting on the UCP. It's like butter now.
what is UCP?
__________________
2021 M2C HS/6MT/Exec/Moonroof
Appreciate 0
      10-07-2020, 11:33 AM   #81
chris719
Major General
7272
Rep
7,252
Posts

Drives: '08 M Roadster
Join Date: Oct 2007
Location: NJ

iTrader: (0)

Quote:
Originally Posted by boss2k View Post
what is UCP?
Ultimate Clutch Pedal
Appreciate 0
      10-07-2020, 12:24 PM   #82
RocketBoots
Colonel
RocketBoots's Avatar
United_States
1859
Rep
2,104
Posts

Drives: Horse Drawn Carriage
Join Date: Jan 2014
Location: Bay Area

iTrader: (3)

Quote:
Originally Posted by j23 View Post
I'm definitely in the minority here, but I didn't like my AS SSK. I had it in both 20% and 30% reduction on prior BMW's paired with CDV delete. I loved them initially because shifting felt very precise and the throws were shortened. However, over time, I realized that the shifter was more finicky than I wanted. It required a lot more effort to get the shifts crisp. Colder weather is when the shifter really struggled and felt a lot more notchy than a stock shifter. Miss-shifts were more common, as well.

The stock shifter on the M2C gets a lot of heat from the SSK crowd, but it's actually an amazing piece. Now I understand why it works and feels the way it does. The little bit of slop is built-in there for a reason. Missing a shift is virtually impossible. It works great and never locks up on me like downshifts with the AS SSK did, especially during hard cornering at autocross.
You definitely are in the minority. Have you tried the AS SSK on the M2? It is easier to get into gear than previous ones, like, say, the E46.

The AS SSK has an ever-so-slight amount of play; it is definitely more precise and notchy (but isn't that the point?)

I would never call the stock shifter 'an amazing piece'. Compared to many other shifters (S2K, Porsche, Miata, BRZ) it's quite rubbery, sloppy, and vague. What I will say is that it's very easy and forgiving though.

Quote:
Originally Posted by Thescout13 View Post
Stock setting on the UCP. It's like butter now.
What he said. The UCP has 3 settings: Stock, Sport, and Race. I had mine on Sport, the middle of the road, for a long time before I was clued in to the Stock setting. Race and Sport can be good, but Stock is just more linear IME.
Appreciate 1
Kleinacus671.00
      10-07-2020, 03:50 PM   #83
boss2k
Colonel
1039
Rep
2,756
Posts

Drives: 2021 M2C
Join Date: Jan 2010
Location: Atlanta

iTrader: (2)

Quote:
Originally Posted by chris719 View Post
Ultimate Clutch Pedal
does that come with a clutch stop or CDV delete?
__________________
2021 M2C HS/6MT/Exec/Moonroof
Appreciate 0
      10-07-2020, 04:09 PM   #84
2020M2Competition
Lieutenant
2020M2Competition's Avatar
429
Rep
433
Posts

Drives: Yes
Join Date: Oct 2016
Location: Florida

iTrader: (1)

Quote:
Originally Posted by boss2k View Post
does that come with a clutch stop or CDV delete?
The UCP comes with a clutch stop

The CDV delete is done by either modifying your existing clutch slave cylinder or using an E90 clutch slave cylinder (21526785964)
Appreciate 1
boss2k1039.00
      10-07-2020, 06:22 PM   #85
flybigjet
Remove Before Flight
flybigjet's Avatar
United_States
6616
Rep
1,598
Posts

Drives: M2C & Boeing's light twin
Join Date: Dec 2019
Location: Littleton (Denver), CO

iTrader: (1)

Quote:
Originally Posted by 2020M2Competition View Post
The UCP comes with a clutch stop

The CDV delete is done by either modifying your existing clutch slave cylinder or using an E90 clutch slave cylinder (21526785964)
Just buy the e90 part-- it's not outrageous, and there have been a fair number of reports of leaking after the DIY "Drill out" method of the CDV.
Appreciate 0
      10-07-2020, 07:29 PM   #86
j23
Lieutenant
United_States
655
Rep
501
Posts

Drives: 2021 M2C
Join Date: Aug 2020
Location: IL

iTrader: (0)

Quote:
Originally Posted by RocketBoots View Post
Quote:
Originally Posted by j23 View Post
I'm definitely in the minority here, but I didn't like my AS SSK. I had it in both 20% and 30% reduction on prior BMW's paired with CDV delete. I loved them initially because shifting felt very precise and the throws were shortened. However, over time, I realized that the shifter was more finicky than I wanted. It required a lot more effort to get the shifts crisp. Colder weather is when the shifter really struggled and felt a lot more notchy than a stock shifter. Miss-shifts were more common, as well.

The stock shifter on the M2C gets a lot of heat from the SSK crowd, but it's actually an amazing piece. Now I understand why it works and feels the way it does. The little bit of slop is built-in there for a reason. Missing a shift is virtually impossible. It works great and never locks up on me like downshifts with the AS SSK did, especially during hard cornering at autocross.
You definitely are in the minority. Have you tried the AS SSK on the M2? It is easier to get into gear than previous ones, like, say, the E46.

The AS SSK has an ever-so-slight amount of play; it is definitely more precise and notchy (but isn't that the point?)

I would never call the stock shifter 'an amazing piece'. Compared to many other shifters (S2K, Porsche, Miata, BRZ) it's quite rubbery, sloppy, and vague. What I will say is that it's very easy and forgiving though.

Quote:
Originally Posted by Thescout13 View Post
Stock setting on the UCP. It's like butter now.
What he said. The UCP has 3 settings: Stock, Sport, and Race. I had mine on Sport, the middle of the road, for a long time before I was clued in to the Stock setting. Race and Sport can be good, but Stock is just more linear IME.
To each his own. I don't actually like the boy ricer feel of the S2K shifter. I prefer shifters with more play and longer throws. The "rubbery" feeling is by design and so is the slop. To me, the stock M2 shifter is more fun and more precise at the end of the day. The BMW shifter is actually an amazing piece of engineering. Just because it doesn't feel like the S2K shifter doesn't mean it's inferior.
Appreciate 0
      10-08-2020, 09:25 AM   #87
boss2k
Colonel
1039
Rep
2,756
Posts

Drives: 2021 M2C
Join Date: Jan 2010
Location: Atlanta

iTrader: (2)

Quote:
Originally Posted by j23 View Post
To each his own. I don't actually like the boy ricer feel of the S2K shifter. I prefer shifters with more play and longer throws. The "rubbery" feeling is by design and so is the slop. To me, the stock M2 shifter is more fun and more precise at the end of the day. The BMW shifter is actually an amazing piece of engineering. Just because it doesn't feel like the S2K shifter doesn't mean it's inferior.
You are one of a kind , have you driven a S2K and you are the 1st person i heard who doesnt like that shifter, its the best
__________________
2021 M2C HS/6MT/Exec/Moonroof
Appreciate 2
CTSean323.00
chris7197271.50
      10-08-2020, 10:51 AM   #88
nearwater4me
Colonel
1910
Rep
2,127
Posts

Drives: '22 G82 Base
Join Date: Sep 2019
Location: GA

iTrader: (1)

Quote:
Originally Posted by boss2k View Post
You are one of a kind , have you driven a S2K and you are the 1st person i heard who doesnt like that shifter, its the best
I owned an ‘07 Silverstone and although I really enjoyed the car and the shifter, I also like the M2 shifter in a different kind of way.
Not everyone wants a mechanical feeling, notchy shifter.
Appreciate 0
Post Reply

Bookmarks

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -5. The time now is 05:34 AM.




m2
Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
1Addicts.com, BIMMERPOST.com, E90Post.com, F30Post.com, M3Post.com, ZPost.com, 5Post.com, 6Post.com, 7Post.com, XBimmers.com logo and trademark are properties of BIMMERPOST