1 M CDV Delete - Holy Crap!!

[RaptorKTM]

OK,

You do not have to go to the extreme I went to do it if you for some reason dont want to. Bleeding the brakes for me was a must because I am introducing air into the system so I didnt see how taking an extra 5 minutes was going to hurt. You dont have to bleed anything like many did, I however do I not agree with that at all. I also dont agree with pinching the line. All those ideas are asking for future issues.

You can simply take the CDV off loose a bit of fluid, pump the clutch then bleed if you choose to. I simply described the way I choose to go about it.

[CarJunkie]

Someone please correct me if I am wrong, but this is how I understand it:

The brake master cylinder and clutch master cylinder both draw from the same reservoir, but they are not otherwise connected. I don't see how air in the clutch line could ever make it into the brake lines. The reservoir already has air in it. All that matters is that the reservoir level never falls below minimum when bleeding either system.

Does bleeding the clutch line require opening and closing the bleeder screw, or does it only require several pumps of the pedal (as suggested in a different thread here)??

[RaptorKTM]

I can not tell you exactly, but I can tell you that air was discharged from both clutch and brake lines after removal. Not much from brakes, but there was certainly air. The clutch bleeder is a definite must, quite a bit of air there.

[bdaddylo]

Originally Posted by CarJunkie

Someone please correct me if I am wrong, but this is how I understand it:

The brake master cylinder and clutch master cylinder both draw from the same reservoir, but they are not otherwise connected. I don't see how air in the clutch line could ever make it into the brake lines. The reservoir already has air in it. All that matters is that the reservoir level never falls below minimum when bleeding either system.

Does bleeding the clutch line require opening and closing the bleeder screw, or does it only require several pumps of the pedal (as suggested in a different thread here)??

Yes, there's a bleeder screw. Franklinjoseph and I did mine today. Once you open the system, it is inevitable to introduce air into the system, so why not bleed it to get the air out?!?!

[Zuzu]

Originally Posted by Zuzu

Great mod.. Drove it straight to my workshop after delivery and replaced the CDV.. After replacing it on my 135i, it was my No 1 mod for the 1M..

And NO... you dont have to bleed the brakes NOR the clutch if replaced correctly.. My tech just R & R the CDV..No bleeding of any kind required, if done professionly..

Originally Posted by CarJunkie

Can you clarify the bleeding . . . The brakes should NOT need any bleeding correct?

IIRC, bleeding the clutch only requires about 10 pumps of the pedal, no need for a pressure bleeder.

No need for BLEEDING of any kind if correctly installed..

[rapter]

Originally Posted by firechicken99

I am already running RBF600




Has that been your experience? When talking with other members it was generally noted the changes should be a bit less often than that, maybe twice a year. (note the car is road driven with a once a month HPDE/Time Attack if I can make it, and auto X etc.) so i am not racing it every weekend.

It all depends on the heat cycles and how much heat is generated into the fluid through use. Given that the car is so much heavier than the bike it would stand to reason brake temps would measure higher for longer. This would equate to more frequent fluid changes.

[CarJunkie]

Originally Posted by bdaddylo

Yes, there's a bleeder screw. Franklinjoseph and I did mine today. Once you open the system, it is inevitable to introduce air into the system, so why not bleed it to get the air out?!?!

Someone in another CDV thread had suggested that simply pumping the clutch pedal about 10 times would clear the clutch line of air. I am not sure how that would work. I can bleed the clutch line the traditional way, it just makes the job a little longer.

[MrRoboto]

Don't be intimidated by this mod. It is very simple. Only a few drops of fluid are lost. Top up the fluid, pump the clutch, and you're done. Also, don't waste your money on buying a new valve. Tap out the restrictor plate from the original and reuse it.

[HALOTHANE]

Autowerke techs simply pump the clutch pedal about 50 times to bleed the system after cdv mod. It's a SELF-BLEEDING system. The pedal will often drop to the floor due to air entrainment at the beginning. As it is pumped, however, it returns to normal travel length and friction as the air is expelled. You must push AND pull the clutch pedal at the beginning due to this. You will see the air bubble into the reservoir tank. Consequently, the reservoir tank cap must be OPEN to use this technique or the pressure accumulation will negate any significant bleeding.

DO NOT clamp the lines.

DO NOT drill the cdv

DO refill the reservoir tank

DO open the reservoir tank refill cap

NO NEED to use the bleed valve

Good luck!

[Papethova]

There is a whole thread here

http://www.1addicts.com/forums/showthread.php?t=209440

[VO 1M]

does anyone with the CDV delete also track their car? On the track with a lot of high rev shifting I am not really convinced of the cdv delete
For daily driving it is really great though.

[firechicken99]

Originally Posted by 1MVO

Autowerke techs simply pump the clutch pedal about 50 times to bleed the system after cdv mod. It's a SELF-BLEEDING system. The pedal will often drop to the floor due to air entrainment at the beginning. As it is pumped, however, it returns to normal travel length and friction as the air is expelled. You must push AND pull the clutch pedal at the beginning due to this. You will see the air bubble into the reservoir tank. Consequently, the reservoir tank cap must be OPEN to use this technique or the pressure accumulation will negate any significant bleeding.

DO NOT clamp the lines.

DO NOT drill the cdv

DO refill the reservoir tank

DO open the reservoir tank refill cap

NO NEED to use the bleed valve

Good luck!

anyone else ever heard of/done this?

[RaptorKTM]

Originally Posted by VO 1M

does anyone with the CDV delete also track their car? On the track with a lot of high rev shifting I am not really convinced of the cdv delete
For daily driving it is really great though.

I do and I can tell you that having a CDV takes away full control and speed in which the system reacts, on the track a big key is being smooth, with a cdv in especially at high speed you want to be smooth, well with the CDV the restriction prevents quick reaction of of the clutch which in turn adds premature wear on the clutch an brakes because of it. The CDV valve is really a NOOB preventative devise.

[MrRoboto]

No drilling required to modify the stock CDV. Just gently tap it with a punch or allen key.

[VO 1M]

Originally Posted by RaptorKTM

I do and I can tell you that having a CDV takes away full control and speed in which the system reacts, on the track a big key is being smooth, with a cdv in especially at high speed you want to be smooth, well with the CDV the restriction prevents quick reaction of of the clutch which in turn adds premature wear on the clutch an brakes because of it. The CDV valve is really a NOOB preventative devise.

ok. I had quite done drive train noise will shifting (fast) up and down (with rev matching) which I am not used to. Maybe I'm just a NOOB

[JimD]

Another thing the CDV avoids is the full shock of dumping the clutch on a reved up engine on the drive train. When I want to start quickly, I rev to 2500-3000 rpm and just drop the clutch. On my 128i, and with the CDV in place, I am not concerned about damaging the clutch, or rear end, or drive shafts. On a 1M, if you do the same or worse, your potential for issues is greater. I don't know if it is still up but there used to be a thread I found by googling of a M3 driver that peeled the splines off his drive shafts doing hard starts at a drag racing track.

I can drive my car smoothly with the CDV in place and I suspect you can too if you want to. If you prefer to have more feel for the clutch engagement point, I can understand that, but it may be important to remember that our drivertrains are not bullet proof and you are eliminating a form of shock limitation for them so you need to compensate. Smoothly letting the clutch out even on a hard start instead of just dropping it might help you keep things intact if you delete the CDV.

Jim

[KingOfJericho]

Launches and quick starts are not what makes the CDV annoying, it's the 1-2 shifts that are choppy. Removing mine was the best mod I've done as far as improving the drivability of the car. I should also add that I've never dumped the clutch in the car in nearly 3 years of ownership so that is not an issue.

[RaptorKTM]

Originally Posted by KingOfJericho

Launches and quick starts are not what makes the CDV annoying, it's the 1-2 shifts that are choppy. Removing mine was the best mod I've done as far as improving the drivability of the car. I should also add that I've never dumped the clutch in the car in nearly 3 years of ownership so that is not an issue.

+1 Ive never dumped the clutch, and never find myself ever "drag racing" if anything I would potentially do pulls from 40-80 type thing.

I might also add the CDV adds premature wear to the clutch, to instead prevent damage to the axles, cv's etc. But for an experienced driver I think they would take a clutch with actual pedal feel then a numb pedal.

[m3dragon]

Originally Posted by Mr.Metak2you

Bay Area- Alekshop
Sactown- Schatz & Krum

IPB Autosport is who I use on C street. Ron is the owner, tell him Adam sent you. If he does not take care of you I will take out his website HAHA

[lcrain]

I have a track weekend coming up in a month. I am having my car inspected for the track tomorrow. I plan to have the brake fluid/oil replaced after the track day. My car has 4700 miles.

Question: Should I have the CDV removed before I head to the track when I get it inspected or just wait until I have the fluids replaced? I can't really complain about the shifting but if removing the CDV makes that much of a difference, I want to see what it is all about.

[RaptorKTM]

My opinion would be to remove it for sure, the difference to me was pretty substantial

[ayao]

I saw them on the sac CCA website but man they wanted $220 for the install. Schatz wanted $200. Back on the fence ...

Originally Posted by m3dragon

IPB Autosport is who I use on C street. Ron is the owner, tell him Adam sent you. If he does not take care of you I will take out his website HAHA