BMW 1 Series Coupe Forum / 1 Series Convertible Forum (1M / tii / 135i / 128i / Coupe / Cabrio / Hatchback) (BMW E82 E88 128i 130i 135i)
 





 

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      07-22-2007, 01:29 AM   #1
jasper
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Will the 1-series have a CDV?

I know it's early to say, but the Mini does not and the 3-series does, so which way will the 1 lean?:iono:
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      07-22-2007, 08:07 AM   #2
larryn
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335i has one. I see no reason why the 135i wouldn't. Luckily, it's an easy and cheap modification.
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      07-22-2007, 10:10 AM   #3
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What exactly is a CDV?
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      07-22-2007, 10:17 AM   #4
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Quote:
Originally Posted by MPower View Post
What exactly is a CDV?
It stands for Clutch Delay Valve...
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      07-22-2007, 10:38 AM   #5
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It's a value that limits the flow of hydraulic fluid to the clutch, showing down it's open/close functions. It's supposedly put in place to make the clutch plate and throwout bearings last longer.
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      07-22-2007, 11:33 AM   #6
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I think it's to reduce abuse on the drivetrain during spirited manuevers. think of it like those hinges on cabniet doors. That have that soft open/close feature.
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      07-22-2007, 01:00 PM   #7
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Quote:
Originally Posted by larryn View Post
It's a value that limits the flow of hydraulic fluid to the clutch, showing down it's open/close functions. It's supposedly put in place to make the clutch plate and throwout bearings last longer.
that is correct Larryn.

and you're right guys, I don't see why they wouldnt put the CDV in the 135i
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      07-23-2007, 09:41 AM   #8
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Quote:
Originally Posted by larryn View Post
It's a value that limits the flow of hydraulic fluid to the clutch, showing down it's open/close functions. It's supposedly put in place to make the clutch plate and throwout bearings last longer.
Awesome. Thanks. That adds another thing to my "learned something new" list.
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      07-23-2007, 10:48 AM   #9
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Isn't that something that usually ends up being "accidentally" disabled somehow...on occasion...
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      07-25-2007, 07:13 PM   #10
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What are the downsides of the CDV? Does it effect driving or make driving more difficult? If all it does is prevent crap from breaking then what's the big deal? If the only downside is adding .1 second per shift then what is the problem?
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      07-25-2007, 07:18 PM   #11
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Theory of Operation - What is a CDV?
The Clutch Delay Valve (CDV) is a one-way restrictor installed by the factory between the clutch slave cylinder and clutch master cylinder, as shown in Figure 1. It "delays" the engagement of the clutch, much like old record players used a damped tone-arm to gently lower the needle onto the surface of a record.
Because of this valve, no matter how quickly you lift your foot off the clutch pedal, the clutch engages the flywheel at a constant (slow) rate. In theory, it can save the driveline from shock, were an inexperienced (or immature) driver to dump the clutch at high RPM. But in practice, all it does is prematurely wear out the clutch and turn experienced drivers into people who, despite 20 years of practice, cannot shift gears smoothly. During parallel parking maneuvers, the delay can be infuriating, causing constant clutch slippage. And during hard acceleration, the large amount of clutch slippage can greatly shorten the life of your clutch. During normal, sedate driving, the shift from first into second gear is often jerky, leading passengers to question your skill. As the driver, you can see your passengers' heads bobbing back and forth during every shift! Yes, in their minds, they are laughing at you.
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      07-25-2007, 09:03 PM   #12
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So that's what I can blame 30 years of crappy shifting on! ; -)
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      07-25-2007, 09:06 PM   #13
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Quote:
Originally Posted by DimaGt View Post
Theory of Operation - What is a CDV?

The Clutch Delay Valve (CDV) is a one-way restrictor installed by the factory between the clutch slave cylinder and clutch master cylinder, as shown in Figure 1. It "delays" the engagement of the clutch, much like old record players used a damped tone-arm to gently lower the needle onto the surface of a record.
Because of this valve, no matter how quickly you lift your foot off the clutch pedal, the clutch engages the flywheel at a constant (slow) rate. In theory, it can save the driveline from shock, were an inexperienced (or immature) driver to dump the clutch at high RPM. But in practice, all it does is prematurely wear out the clutch and turn experienced drivers into people who, despite 20 years of practice, cannot shift gears smoothly. During parallel parking maneuvers, the delay can be infuriating, causing constant clutch slippage. And during hard acceleration, the large amount of clutch slippage can greatly shorten the life of your clutch. During normal, sedate driving, the shift from first into second gear is often jerky, leading passengers to question your skill. As the driver, you can see your passengers' heads bobbing back and forth during every shift! Yes, in their minds, they are laughing at you.

i think it would be better w ith out it
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      07-25-2007, 09:40 PM   #14
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Quote:
Originally Posted by ice13water View Post
i think it would be better w ith out it
Yes, it absolutely is better w/o the CDV.
It was the first thing I did to my Z.

It was a day/night type of experience
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      07-25-2007, 09:47 PM   #15
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Taking CDV out, will be the first thing I'll do.. .(if I'll get 135i)
You guys should read what e46 M3 guys are saying about CDV, the feel of the clutch before and after. It seems significant...
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      07-25-2007, 11:09 PM   #16
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I just replaced my original clutch at 183k miles because the throwout bearing failed. The clutch wasn't even done yet. So, a CDV may cause more wear but it's nothing significant. I just installed a new clutch with a lightweight flywheel. With that said, my friend has the exact same set up with the CDV removed...it's sooo much better. The clutch just feels like it grabs better. I need to get mine out ASAP. And then in my future 135i
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      07-26-2007, 08:34 AM   #17
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how much would it cost to remove it
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      07-26-2007, 11:28 AM   #18
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Quote:
Originally Posted by ice13water View Post
how much would it cost to remove it
Cost me $20 cash.
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      07-26-2007, 11:32 AM   #19
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Quote:
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Cost me $20 cash.
Is it very accessible for a DIY?
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      07-26-2007, 11:39 AM   #20
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Quote:
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Is it very accessible for a DIY?
Yeah... if you're OK with bleeding the line after.
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      07-26-2007, 11:45 AM   #21
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Quote:
Originally Posted by inTgr8r View Post
Yes, it absolutely is better w/o the CDV.
It was the first thing I did to my Z.

It was a day/night type of experience
As long as it can be taken out. Ill be doing it right away. I noticed that delay when driving the 335i and hated it.
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      07-26-2007, 12:15 PM   #22
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Quote:
Originally Posted by inTgr8r View Post
Yeah... if you're OK with bleeding the line after.
I am, as long as it works with the same brake bleeder from my Porsches. I assume the same reservoir is shared by the brakes and clutch?
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