Clutch Delay Valve (CDV)??

[Matt Q]

Here are some writeups from my research before I removed mine

http://www.bimmerfest.com/forums/showthread.php?t=55083
http://www.e90post.com/forums/showthread.php?t=374225

Also if you have an M3... always go and see what MadRussian as to say - Loads of good info there

http://m3.madrussian.net/diy_cdv.shtml

I hope this helps

 

[Philip Foglar]

Thanks for the info and reply Matt! Will have to consider doing this at some point because me isn't always liking this numb clutch arrangement...

Edit: Will have a look through those links, thanks! Actually read about it on the E90 forum but thought I'd ask here...

Philip

 

[Ziyaad]

i read about this a while ago..& i will def. be doing this when i get my 4 pipe (if its not SMG):thumbsup:

 

[applehero]

Lets do a group meetup in JHB and all do it

+1 !

 

[rick540]

I wonder whether BMW fitting the CDV was to modify the feel or prevent breakages?

 

[ruaangrobler]

OK, this seems the right place to ask a question I've been manning up to ask: :drama:

What is the best way to drive a manual bmw - specifically something like the e46 330i?

I know lots of people are going 'aw, who let this :jack: on' now, but honestly. My only previous car was a 1300 citi golf. I have no other friends to really compare with since my only mate who drives a bmw is a long way away and has a modded e36 - so it's a little different. I've heard many people talk about people who don't shift the way they should, or don't use the clutch correctly. As far as I can tell I'm not doing a bad job...but again - I can't compare to anyone.

I mean, I release the Loud pedal, step on the clutch, when it's all the way down I slot into the next gear, clutch out, accelerator on. On pull offs I sometimes 'slingshot' the clutch - ie let it have that sweet spot for just a split second before releasing it. This seems to give me the fastest launch, but I don't want to be hurting my baby in the process of discovering my inner Stig.

So basically, I like the idea of the CDV removal, as I've alway been surprised that my golf felt a bit more 'involved' in the clutch department, and now I know what to blame. I just want to know that I won't break my baby by driving like an idiot - however that may be.

So..before being a$$holes(I mean this lightly of course, since I know you're nice guys...in general), please remember some of us are young and inexperienced enthusiasts. fft:

Plus, it's not like I'm telling Matt to go get his car turbo'd by Sav (I still laugh about that regularly)

 

[Matt Q]

So..before being a$$holes(I mean this lightly of course, since I know you're nice guys...in general), please remember some of us are young and inexperienced enthusiasts. fft:

Plus, it's not like I'm telling Matt to go get his car turbo'd by Sav (I still laugh about that regularly)

- I'll be gentle since it's Friday and I'm still stoned from last night...

Removal of the CDV will (to a certain extent) shrink the sweet spot.. however the toss up is that your pedal feel and feedback is increased.. so basically you are now aiming for a smaller target with a better gun... if that makes any sense??

Removal of the CDV also raises the ceiling on where you can take the driving experience but also opens the door to cataclysmic clutch damage.

So my advice to you young Skywalker ... there is a point where the clutch grabs (generally quite deep down on Bimmers) which you need to get used to finding... the trick is to get to that spot as quickly as possible and then do the job of the CDV with your foot.. in other words, release the clutch quickly till the point it STARTS to bite.. then slow down your foot and feed more petrol... always slip the last little bit and practise making this last little slip faster and smoother... if it grabs it's too fast... if you hear and feel engine revs rising without a corresponding increase in power to the wheels then you are slipping too slowly.

So it's:

1. PETROL - OFF

2. CLUTCH - FAST IN

3. GEAR CHANGE

4a) CLUTCH - FAST OUT (to grab point)
4b) CLUTCH - SLIP & PETROL - SLIP (so now your feet are gently moving in opposite directions)

5 PETROL - ON

1-4a happens in an fluid instant

4b can take as long as 1 second

5 is instant

Provided you are smooth with the power and clutch you can practise a fair amount of slipping without causing damage... remember that slipping on the power is especially important in heavy cornering as you dont want to "LOAD" the rear of the car with power when you are turning.. unless you want to oversteer and slide

Loading the rear is also the start of learning to drive using not only your steering but also your power to bring the rear out and corner sharper without losing engine speed.. something you cant do in a front wheel golf as easily

Did this help at all??

 

[ruaangrobler]

Matt sir (or should I say Qui Gon Matt), I bow low in appreciation for a thorough piece of feedback and advice.

Thanks goodness it sounds like I've been on the right track all along. I'll start playing with (4b) a bit more on gearchanges, as I think I've been overlooking the slip a bit(it's so quick though) - But I do it on pull-offs.

One more thing - the gearchange - I like being rather brisk (yes, it's a euphemism), but have always been told that snap changes do damage. Is there truth in this - is it gearbox dependent? My argument has always been that once the clutch is down, the change can happen quickly - otherwise these fancy new step-tronic 'change in the blink of an eye' boxes would break themselves.

Your opinion on this?

And yes, this helps a lot to put my mind at ease that what feels best, is right, and I'm not breaking my baby.

:thumbsup:

 

[Philip Foglar]

Thanks for the explanation Matt! I think to a large extent this is what most good drivers do step for step in the fractions of a second that occupies a good and precise gear change. For normal driving conditions the idea is to change gear so that other than a brief reduction of acceleration it can't be felt. On more dynamic driving the gear changes are often part of the controlling the car's attitude around corners etc - something as you where a rear wheel drive can be so good at!

As for quick changes, I would think that the gearboxes should be tough enough to cope provided the changes are done correctly. I stand to be corrected, but the manual gearbox is mechanically the same as the SMG gearbox which of course does not have the CDV I believe. So the inner working of the gearbox can cope with SMG type lightning fast gear changes... Not sure if my impression of this is correct though but it makes sense.

 

[Matt Q]

Matt sir (or should I say Qui Gon Matt), I bow low in appreciation for a thorough piece of feedback and advice.

Not Qui Gon yet... but you can call me Si Heng Matt if you must

Don't worry about fast changes, the ZF gear boxes is very strong. Just keep it accurate and never force a change...

Here's one important gearing tip to long gearbox life which most people don't know.... when you have changed gears TAKE YOUR HAND OFF THE STICK

Many times we change and then keep the hand on.. or sometimes when cruising you may find your hand resting on the level or even wiggling it (sound familiar?!)

Once the clutch is out, the stick and the gear box are full connected so any movement on the stick actually puts minute sideways strain on all the moving parts.. not a good thing and it also wears out linkages and the bushes on your gear, your gear ball and the bushes on the SR (Selector Rod)

There is a plastic ball joint at the base of the gear stick (not mine.. had a stainless steel replacement made by UUC) which slowly wears out to become oval and leads to play in the gear lever in older cars.. the more you play with the lever when the gear is in.. the more it wears

 

[ruaangrobler]

[/quote]
There is a plastic ball joint at the base of the gear stick (not mine.. had a stainless steel replacement made by UUC) which slowly wears out to become oval and leads to play in the gear lever in older cars.. the more you play with the lever when the gear is in.. the more it wears
[/quote]

Wow, Si Heng, that sounds like something BMW should've done! I'm sure they have they're reasons. Probably lasts 70% as long at 10% of the price - which is fair.

Damnit, now I just wanna get up from behind my desk, grab my car keys and go practice!!!

And Philip, thanks for your input too - I see you have a 330i, you must be a good man:clap: (what, that's not biased)

So right, I think this is one mod that is definately being added to my to do list. After all, I'm not gonna pursue power as much as a better 'feel' - I want better response in the end - my car's fast enough for now...when I'm ready I'll move into the //M VIP section. I believe naked women fall from the heavens there!? - As long as they don't land on my car and dent it.

Big Respect
the humble si-dai

 

[Sankekur]

Thanks for all this great info Matt. Resting your hand on the gearknob does sound very fimiliar, guess I will have to stop doing it

 

[Matt Q]

the OEM plastic ball (actually a kind of nylon) is super hard wearing and very slipper.. but it still wears out.. the UUC ultimate shortshifter is made from a solid piece of stainless which is shaped to fit and coated with an uBer long lasting lubricant (mmmm lubricant!)

It has a notchy feel and is very directional.. if somewhat harsh.. which I like

I still rate a big brake kit and a shortshifter with a DSSR (Direct Sheer Shift Rod) as my 2 favorite mods (besides FI) in terms of cost VS the real difference it they make to driving pleasure

I cannot stress enough how lovely a shortshifter is


FROM UUC SITE

UUC's years of shifter experience and continual development have resulted in a major upgrade to our product, the all-new EVO3.

What's new with EVO3? Everything.

Every part of the EVO3 has been changed from EVO2. Superficial appearance shows little difference, but every internal component, dimension, and hardware piece has been changed. While keeping within the basic design of the earlier EVO2, the EVO3 is as close to a "clean sheet" design as possible.

Important upgrade points:

Subjectively 20% effort reduction compared to EVO2, very close to stock effort feel. This is accomplished by a complete reconfiguration of lever dimensions, linkage geometry, and all friction and pivot points in the assembly.

This results in the smoothest and least-notchy shifter available. Due to the increased precision and smoothness of the assembly, shift effort is only slightly increased over the original BMW setup.

The exact same 35% reduction in shift travel (100mm from 3rd gear to 4th gear total travel) is retained at stock height, and down to over 40% when height is adjusted to the short end of the adjustment range.

Completely self-contained and self-adjusting primary pivot bearing assembly. Unlike the original BMW pivot bushing cup setup, our new bearing system is not open to outside contamination (underside of the car in the BMW shifter assembly is exposed to road dirt) and will retain lubrication, keep out the grit that "roughens" a shifter feel over time (and destroys plastic ball pivots like the OE and many aftermarket units), and positions the shifter assembly perfectly for ideal linkage alignment.

New full-length internal vibration absorbing material that surpasses any OE or aftermarket material for longevity and retention of design specifications.

New standard lower pivot bearing setup with enhanced ease of installation.

 

[ruaangrobler]

Ooooh, it's piiiirtie.

Thanks Matt.

I just youtubed it a bit, and what's really noticeable (I watched 330i related clips) is how much better the shift from the UUC product looks compared to the cheaper stuff, eg. Ebay.

I'll look into this at some point, but will save it for later, my car's shift action is already pretty short. I'll consider this after the other plans I have - since my car's still my daily comfortable cruiser.

Bigger brakes I'll come back to talk to you about when my car's faster, but for the current use and power, my brakes are more than adequite.

But on Topic - I've noticed and played a bit this weekend - and I've indeed been doing my shifts as you recommended

So I think that CDV mod might(purely cash restrictions) be in my not-too-distant future.

Thank you all for what turned out to be a very informative discussion.

 

[Sankekur]

If I am not mistaken the CDV delete shouldn't be that expensive and if someone on the forum helps you it could be even less so, as I understand it, you clamp the rubber clutch line then you just remove the valve, connect the to pipes and bleed the clutch (Of course nothing is ever as simple as it seems so I don't want to be the one that over-simplyfies this)

 

[ruaangrobler]

Yeah, I know, I just should really start being choosy about my cash expenditure as my current work contract ends in December, and I need to save every cent I can incase things don't go too well after that. - I don't want to lose my car if I can't find good work (take the house, just leave the car!!!)

But if I get the all clear that future work is in place, then I think my CDV can kiss it's life goodbye, as well as my cats probably (but that's a story for another thread). - I'll replace them with Lions!! Roaarrrr (sorry, coffee high)

Thanks for the good suggestion though, and I will definately get one of the wizzes to help me (if they're willing) when I get around to it, as I really want to get into doing all my own work where possible.

 

[Phoenix]

Does the '95 328i have one?

 

[Sankekur]

It doesn't look like it on realOEM, but the best way would be to check, search a bit on the internetz for what it looks like, then jack up the car and have a look, and you should easily be able to determine wheter you have one

 

[Philip Foglar]

Does the '95 328i have one?

From what I remember reading it was only the much later E36's (just before the E46's came out) that had the CDV implemented.

Philip

 

[Phoenix]

Thanks for the feedback! Appreciate it!