CDV delete, clutch spring removal, and/or UCP?

[Jobon]

I've been driving automatic cars for the past 15 years and decided to finally take the plunge into learning to drive stick. I've been teaching myself using a 2008 BMW 135i.

This is the first clutch pedal I've ever used and my first impressions were that the clutch pedal has to go a looooong way to bottom out (I'm only about 5'2"), it can be difficult to maintain steady pressure when releasing the pedal as the amount of pressure being applied to bring the pedal back into place seems to be non-linear across the throw, and lastly, it seems difficult to "feel" when the clutch has engaged.

As I've been perusing these forums it seems that some of what I'm feeling is not unexpected in these cars and there are some modifications people do to "resolve" them. I personally don't know if I prefer the clutch the way it is or not as I have nothing to compare it to.

The modifications generally talked about seem to be deleting or replacing the clutch delay valve, replacing the pedal with the UCP, or removing the clutch pedal spring.

All that being said, given that I'm using the car to learn, I was hoping to get some input on if any of these modifications might help me to better learn to drive any manual car, not just this one, as I don't want to build "bad habits" with a clutch pedal that behaves differently from most. Or am I just going down a rabbit hole here for no reason and the stock clutch setup is perfectly reasonable to learn on?

Bonus points for anyone who can explain to me in what situations you would want to a CDV delete and which cases you would want to either remove the pedal spring or replace the pedal with a UCP. From what I've been reading, it seems like these modifications are intending to serve a similar purpose - a more consistent clutch pedal feel. But I'm guessing I'm missing something here and maybe if you do one you just always do the other?

[N55e82Simon]

I think learning on the factory clutch is the way to go, if you had years of experience and wanted to tune or tweek it to your preference or driving style I would understand that. Now maybe I’m wrong but I feel like you only have a few months practice right?

And just for a side note. Every car has a different clutch feel and engagement point etc. learning how to drive stick give you the option to “learn” each one on a one on one basis. So you could try driving a few different cars and see what you think but my guess is just going to take some time and you will feel more natural and comfortable etc.

[cerealwars]

Hey Jobon,

I've been driving stick for fifteen years. This E82 I picked up a few months ago has a very vague feel, and a high engagement point. The vague feel comes from the dual-mass flywheel, and the high focus on NVH reduction because this is a luxury car. While the shifter is great, the clutch absolutely sucks.

There's one more modification I noticed you may have missed - replacing the factory clutch stop. This part is what the clutch pedal hits when you mash it to the floor. The throw on this pedal is absurdly long, and the bite point is all the way at the top. So when you go to let the pedal up you have to lift your entire leg, which is cumbersome, fatiguing, and downright stupid. Ideally the bite point would be near the bottom of the travel, so you can simply put your foot to the floor, and lift your toe up, rolling off your heel. In every other car I've owned you can simply adjust the pedal pushrod until the bite point is exactly where you want it. In this car, such an adjustment does not exist.

This is the first modification I did to my car. I bought pickyeater's clutch stop (just google 230519560074) on ebay for $20. It takes less than 5 minutes to install. This will eliminate that useless bottom 70% of clutch travel and make the car much easier to drive.

I have deleted CDVs on other cars before, and it will give you a more reliable clutch feel (the bite point no longer "moves", if that makes sense). If you do perform the CDV delete, I recommend removing the modified clutch stop to get optimal pedal travel for bleeding.

I haven't yet performed the CDV delete on my E82. I am hesitant because it is my daily and I have had some bad experiences bleeding finnicky hydraulics in the past. I will likely try it soon though, as I still feel that the bite point moves sometimes (changes with temperature, also with how rapidly the clutch is depressed/released).

UCP is definitely a more extreme measure, I wouldn't recommend that unless you have tried the other simpler, less intrusive methods first.

Removing the pedal spring also seems iffy to me, I have read mixed reviews and IIRC it is a PITA to re-install if you don't like it.

[tracer bullet]

I don't want to offend anyone but I think the CDV and clutch stop are good beginner tools. After you get experienced neither is needed.

For engagement point it's probably specific to every car, exactly how it was put together, how much life is left in the clutch itself, things like that. It's also relative, high or low could be an opinion based on other cars a person's driven. You can get used to anything if you don't have to jump back and forth between 2 cars with sticks.

Bleeding it isn't too bad but yeah you need at least some knowledge and the right tools. You can't permanently break it trying but you can get pretty frustrated if it's not done right!

[PRTSB1M]

Given this whole thread is subjective, I'll preface that I'm 5'11" (180cm). BMWs may be luxury vehicles in the states, but they are still sold as everyday drivers. I'm not a fan of clutch stops, as any slight movement from the end of travel results in the car moving... get in the car with wet shoes and this could easily lead to unintentional engagement. I would only recommend one for a track car driven on courses with lots of shifting.

I owned/drove several E30s before my first E82, and adjusting to the CDV was annoying for sure; I will remove it when I replace the clutch on my current E82. The CDV is there to intentionally slip the clutch a little (so you don't break the transmission), which is why you can't feel the engagement point reliably. That said, the CDV will kinda force you to learn to shift the car perfectly to achieve smooth shifts; so not bad for beginners, especially with the torque of N54 on the other side.

[AshwinLB]

Originally Posted by cerealwars

I have deleted CDVs on other cars before, and it will give you a more reliable clutch feel (the bite point no longer "moves", if that makes sense). If you do perform the CDV delete, I recommend removing the modified clutch stop to get optimal pedal travel for bleeding.

The clutch on the e82 is actually very easy to bleed. You just have to make sure that the clutch section on the brake reservoir stays topped up and all you have to do is continuously pump the clutch (while bleeder screw is closed) since it’s a self bleeding system. It does take a decent amount of pumps but there’s no risk of air getting in the system

[AshwinLB]

OP I’d definitely say that a clutch stop and CDV delete are very good improvements to the clutch pedal. I installed a BMS version with all 3 spacers and the bite point is perfectly right at the bottom. I was stuck in traffic one day when I first got the car and having to hold the clutch so far really enticed me to buy it right away.

For CDV delete, I only recently did it last month and it made a positive difference. This was my second manual car after a Honda Civic and it was very different due to the CDV. Eventually I got used to driving with it for almost 3 years and now that I actually did the CDV delete, it seems more like a normal car (from my Civic and a TL Type-S experience). It took relearning slightly again since I was so used to driving it a certain way but I’d definitely say I prefer it now since I have much greater control on the clutch engagement. Go for the delete over a new metal fitting since it’s basically free (tho you do need to buy brake fluid to rebleed).

[cerealwars]

Following up here, I performed a CDV delete yesterday and took the car on a good drive. Took about twenty minutes total, super easy. I watched a couple youtube DIYs, used two clamps on the flexhose, and made sure I was prepared to swap hose connections. Spilled about five drops of fluid, didn't need to bleed the system at all.

The engagement feels a lot more natural now. It's enlightening to see the difference. I can feel the clutch irregularities pulsating through the fluid and back on the pedal during engagement. It also allows you to feel when you make a mistake with engagement. It allows you to be better, and it also allows you to be worse. This newfound real-time feedback helps shape me into a smoother driver, and makes the clutch feel like it ought to. Definitely one of the best performance/cost modifications that can be done IMO, and I regret not doing it sooner.

[Tuxedo]

I learned to drive on a MT with a cable clutch, engage / disengage simple. The clutch on an e82 will be a softer feel, almost feels to easy. the oem Valve is going to slow up the fluid on pedal disengagement makes the grab point slower.

I have a style of MT I never apply fuel on clutch engagement, the clutch is completely out when I use the accelerator so I don't need the fluid to slow up at clutch grab.

To learn this technique go to a open parking lot and put the car in 2nd gear, release the clutch pedal slow and steady at idle speed without usage of the other 2 pedals. go forwards and in reverse from 2nd to R a few times using only the clutch. Once you've mastered a smooth motion in both directions replace the oem valve for CDV. imo the other mods will be performance minded and not better.