[BMWnation]

Originally Posted by Indo Rider

Nice. Did you swap the whole assembly or take it apart to remove the restriction? I need to get on this myself but haven't decided which way to go.

The best way is to take the restrictor out, it’s super easy. Cost me $4 for break fluid to bleed the system. One of the best mod for manual trans.

[ashtaron14]

Originally Posted by IL Pete

It was suggested on another thread that you could do a CDV Delete by replacing the Clutch Slave Cylinder with one from an E9x M3. That apparently worked for F8x M3's, and it was speculated/assumed that would work for G8x.

Has anyone tried that method? I sent the above video to a local shop, and they asked if I could just provide that part and they would swap them, versus taking the CDV out of the existing one.

Thanks in advance!

I did this method for my M2 Competition, but the result was that there is an odd sound when you clutch-in, we couldn't fix it but it didn't affect performance. I don't know if it's because the part was defective or that E90 M3 parts are generally old (it's a 10+ years old car, so parts might have been sitting around?).

For the G80 I did the CDV removal instead and there's no funny sound coming from the car. If you or your tech worry, you can always order a new G80 clutch slave and get the CDV removed prior to swapping them.

[BMWnation]

Originally Posted by ashtaron14

I did this method for my M2 Competition, but the result was that there is an odd sound when you clutch-in, we couldn't fix it but it didn't affect performance. I don't know if it's because the part was defective or that E90 M3 parts are generally old (it's a 10+ years old car, so parts might have been sitting around?).

For the G80 I did the CDV removal instead and there's no funny sound coming from the car. If you or your tech worry, you can always order a new G80 clutch slave and get the CDV removed prior to swapping them.

No strange noise at all with mines. It’s sounds better when the clutch engages instead of slow engagement it had previously, and being jerky.

[0Camus0]

I'll be replacing the stock clutch soon, I'll be doing this mod as part of the change.

[translux]

Originally Posted by 0Camus0

I'll be replacing the stock clutch soon, I'll be doing this mod as part of the change.

Interested in details on your clutch swap.
Is the stock one-shot or is this preemptive?
If it's shot or slipping what WHP & WT are you at?
What clutch are you going with?
Thanks in advance.

[mattssi]

What is the purpose or advantage of the cdv? Meaning, why was it engineered in?

[mattssi]

Originally Posted by 0Camus0

I'll be replacing the stock clutch soon, I'll be doing this mod as part of the change.

Make sure to post about it! Looks like the after market ones run about 2k but labor looks like a biotch.

[Gizmo 335i]

Originally Posted by mattssi

What is the purpose or advantage of the cdv? Meaning, why was it engineered in?

It reduces the fluid flow so that full engagement is sort of feathered in. Kind of inhibits powershifting to reduce shock to the system. But the side effect is that the feathering reduces feel.

I replaced the slave cylinder in my M2C. No noises or issues.

[safridi]

Man i wish i knew how to bleed the transmission…..never did it before. Can someone teach me?

[Indo Rider]

Finally did the CDV delete (while installing AA single midpipe and CG valve controller too).

As anticipated, it's sooo much better. It'll take me a bit to re-train myself to not baby the pedal during casual driving, but WOT shifting at redline is back to what it should be.

The bleed process went better than I expected. I'm no expert, but this worked for me:
- Motive power bleeder, no fluid in it, just used it to pressurize the fill reservoir to ~13 psi.
- me under the car working the bleed nipple, wife working the clutch pedal
- pedal to the floor, open bleed valve until I see fluid and air bubbles coming out in the clear tubing attached to the nipple, close valve, pedal up (a few times had to be manually lifted off the floor). I think best to close the valve after you get some fluids/air out, but before fluid completely stops flowing.
- did this at probably 8, maybe 10 times until I wasn't seeing air bubbles, and pedal was coming up on it's own.
- topped off the reservoir with maybe 2 oz of fluid

Thankfully I didn't have to put the car back up on jack stands as the clutch felt good straight away. The whole removal of the restriction was cake with a wood screw. I did use a wrench that I had previously cut in half since there's barely any space to turn the bleed valve.

IMO this is a must. As much as I'm a fan of the MT, it's not right until you get rid of the CDV.

[M4 EM]

Sorry for the dumb question, is there a replacement CDV valve or does the shop have to put the screw and remove the restrictions inside the stock one? If anyone knows of a full DIY video that includes bleeding please share the link. If I find a BMW shop and just say delete my CDV will they know exactly what to do and bleed it correctly?

[Indo Rider]

Originally Posted by M4 EM

Sorry for the dumb question, is there a replacement CDV valve or does the shop have to put the screw and remove the restrictions inside the stock one? If anyone knows of a full DIY video that includes bleeding please share the link. If I find a BMW shop and just say delete my CDV will they know exactly what to do and bleed it correctly?

Removing restriction from stock slave cylinder is best bet since the valve isn't a separate part to remove or replace like other previous generations. Removing the restriction is done same as video on 2nd page of this thread, it's easy. Yes a decent bmw shop should be able to do this and bleed the system properly.

[sbgolfer2221]

Hate to be this guy, but let me guess, if you are worried about keeping your warranty in tact do not do this? Am I right? Hope not

[Gizmo 335i]

Originally Posted by sbgolfer2221

Hate to be this guy, but let me guess, if you are worried about keeping your warranty in tact do not do this? Am I right? Hope not

Most dealers would probably make a fuss if the issue is even remotely related to the delete. Mine would.

[Indo Rider]

Originally Posted by sbgolfer2221

Hate to be this guy, but let me guess, if you are worried about keeping your warranty in tact do not do this? Am I right? Hope not

Probably right, but if you half way know how to drive a manual, and you want to be able to enjoy driving your manual, this mod is 100% worth it. Realistically, since clutch is wear item anyway, you're not very likely to warranty it unless you have a freak premature failure. I suppose it might be easier to break an axel or something if your launching at the drag strip with sticky tires, but that guy isn't asking this question 😉

[AhsanU]

Originally Posted by sbgolfer2221

Hate to be this guy, but let me guess, if you are worried about keeping your warranty in tact do not do this? Am I right? Hope not

If you're worried about warranty, leave your car completely stock. Like, absolutely as it came from the showroom. Yes it's extreme, but it's the only way to guarantee with certainty that you'll get warranty service.

Honestly, BMW have become ridiculous when it comes to denying warranty work. Reading about the forum member that had premature rotor/brake pad wear (I forget which) and got denied a warranty repair because he had spacers that were on his wheels is absurd. The warranty means jack shit to me, which is why I'm fully modified and plan on flash tuning.

[sbgolfer2221]

Originally Posted by Indo Rider

Probably right, but if you half way know how to drive a manual, and you want to be able to enjoy driving your manual, this mod is 100% worth it. Realistically, since clutch is wear item anyway, you're not very likely to warranty it unless you have a freak premature failure. I suppose it might be easier to break an axel or something if your launching at the drag strip with sticky tires, but that guy isn't asking this question 😉

Thank you. So I’m thinking w the CDV delete mod my main risk is the clutch and related parts. Which isn’t a ton, like the engine. I’m thinking if clutch did fail “early” then I would upgrade it on the aftermarket anyway.

[sbgolfer2221]

Originally Posted by AhsanU

If you're worried about warranty, leave your car completely stock. Like, absolutely as it came from the showroom. Yes it's extreme, but it's the only way to guarantee with certainty that you'll get warranty service.

Honestly, BMW have become ridiculous when it comes to denying warranty work. Reading about the forum member that had premature rotor/brake pad wear (I forget which) and got denied a warranty repair because he had spacers that were on his wheels is absurd. The warranty means jack shit to me, which is why I'm fully modified and plan on flash tuning.

Thank you, enjoy your ride! I will too!

[top-down]

I do not have any way to work on my car at home, unfortunately, otherwise I'd try this myself. So I reached out to a "European shop" that specializes in BMW to get a quote for a CDV delete and they said they can't do it.

Is the CDV really that integral to preventative damage of the transmission? Using search it looks like folks have removed it in previous generations... I just wonder if there is any long-term data for transmission issues.

[Gizmo 335i]

Originally Posted by top-down

I do not have any way to work on my car at home, unfortunately, otherwise I'd try this myself. So I reached out to a "European shop" that specializes in BMW to get a quote for a CDV delete and they said they can't do it.

Is the CDV really that integral to preventative damage of the transmission? Using search it looks like folks have removed it in previous generations... I just wonder if there is any long-term data for transmission issues.

Can't do it or won't do it? If they can't do it because of difficulty, I'd run from that shop. Refusing is a different story. But anyway, I did the delete on a 335i and put on 120k miles after that without any sort of issue whatsoever. I have 6k miles on my M2C without issue.

[top-down]

Originally Posted by Gizmo 335i

Can't do it or won't do it? If they can't do it because of difficulty, I'd run from that shop. Refusing is a different story. But anyway, I did the delete on a 335i and put on 120k miles after that without any sort of issue whatsoever. I have 6k miles on my M2C without issue.

Ah good to know, thanks for that info. I assume they "won't". From looking at the youtube video demonstrating it...it does not look that difficult. On the other hand I said I had a 2022 G80 and they thought I meant something called a Genesis. Which I guess is a brand of car by Hyundai(?). I learned something new.

[Indo Rider]

Originally Posted by top-down

Ah good to know, thanks for that info. I assume they "won't". From looking at the youtube video demonstrating it...it does not look that difficult. On the other hand I said I had a 2022 G80 and they thought I meant something called a Genesis. Which I guess is a brand of car by Hyundai(?). I learned something new.

Haha, yeah I hate Hyundai crowding my G80 searches... But about the CDV, my earlier posts in this thread make my position clear. If deleting the CDV wasn't possible I wouldn't even want a manual BMW. It's that bad. Bleeding the clutch is the pain. Removing the little restriction parts is super easy.