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Discussion Starter · #1 ·
Here are some pics of my CDV DIY. Notice how small the orifice is on the valve side (006) of the OEM hose, which connects to the clutch slave. The other side (003) connects to the tubing coming from the brake reservoir.
 

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Thrlls said:
Here are some pics of my CDV DIY. Notice how small the orifice is on the valve side (006) of the OEM hose, which connects to the clutch slave. The other side (003) connects to the tubing coming from the brake reservoir.
Did you notice that the stainless steel one is smaller than stock on the (003) side?
 

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Discussion Starter · #5 ·
Ron Stygar said:
Did you notice that the stainless steel one is smaller than stock on the (003) side?
That's what I thought, but I don't have a caliper to measure, and it seemed rather minute. The difference is not as extreme as the other end, so I'm satisfied with that.
 

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Thrlls said:
That's what I thought, but I don't have a caliper to measure, and it seemed rather minute. The difference is not as extreme as the other end, so I'm satisfied with that.
On the stock M hose, what some are calling the CDV end, measures 1.4mm. The other end measures 3.42 mm. Blowing up your pic and ratio-ing the dimensions to the ones I know, your stainless steel line measures 2.16 mm.
I'll be replacing my stainless steel hose soon with the non M Z3 hose which measures 4.35 mm on each end. When I do, I'll measure my stainless steel one.
 

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Discussion Starter · #7 ·
Ron Stygar said:
On the stock M hose, what some are calling the CDV end, measures 1.4mm. The other end measures 3.42 mm. Blowing up your pic and ratio-ing the dimensions to the ones I know, your stainless steel line measures 2.16 mm.
I'll be replacing my stainless steel hose soon with the non M Z3 hose which measures 4.35 mm on each end. When I do, I'll measure my stainless steel one.
Does this mean the non-M Z3 does not have a CDV? I thought all Z3's had the CDV? Or is the CDV external on the non-M Z3?
Let me know how things go with the non- M hose.
 

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Discussion Starter · #9 ·
Warning for the clumsy at hand!

Well, my friend and I attempted to change out his CDV on his Z3 and it turned out to be a nightmare instead.
First of, he got the wrong SS line, which we didn't notice until the OEM line was removed. Then as we tried to replace the OEM slave after bleeding, the actuator fell into the bell housing :mad:
My friend did not want to remove his trans to get it out, so we had to tow it to a shop. :(
It cost him $150 for the shop to get out the actuator.

The following day I had to get back on the horse, so I changed out my CDV on my roadster just to ensure myself that I could do it. And it was a success! :thumbup:

FYI, the actuator can easily come out of the slave either when removing the slave or reinstalling it so be advised.
Of course none of you may be as clumsy with your paws as I am.
See pis of actuator.
 

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I have heard some people complain about the CDV, but I wonder whats different for me.

I installed a Clutchmasters Stage 1 clutch and a lightweight flywheel not long after I bought the car.

I feel no hesitation if I drop the clutch, the wheels just spin. When I shift at WOT, the car spins in 2nd gear also which implies the clutch is grabbing pretty hard and pretty quick.

Am I missing somthing?
 

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Discussion Starter · #13 ·
daven said:
Ron:
Does the stock Non M hose have the restricted orifice like the M hose?
Thanks
It didn't seem like it did on my friends car. I don't even think his Z3 had a CDV. He basically wanted to have SS lines.
 

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Discussion Starter · #14 ·
JBgotM said:
I have heard some people complain about the CDV, but I wonder whats different for me.

I installed a Clutchmasters Stage 1 clutch and a lightweight flywheel not long after I bought the car.

I feel no hesitation if I drop the clutch, the wheels just spin. When I shift at WOT, the car spins in 2nd gear also which implies the clutch is grabbing pretty hard and pretty quick.

Am I missing somthing?
The differences are subtle as far as the clutch grabbing quickly. Before the removal of the CDV, the clutch had a slight delay where it almost felt like it was slipping. However the reaction is much quicker now.
As for laying rubber down with the OEM clutch, I never had a problem with that, I had more of a problem NOT trying to do it in second as the rear would get too loose.
Again, the difference is subtle, so for some it may not be worth doing, but for me I wanted as much reaction as possible...of course now this means even more control from first to second!
 

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I think it makes my clutch slip at high RPM shifts at like 80 or 100 mph.
 

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Mpire said:
I think it makes my clutch slip at high RPM shifts at like 80 or 100 mph.
I had that at the drag strip after I bought the car, shifting 2-3 and shifting 3-4 the clutch would slip down then catch. Then the clutch slipped once when I tried to spin in 1st and it spun the clutch ALOT. After that I just went and put in the aftermarket clutch and flywheel and it has caught hard everytime since and have ne no evidences of slipping or delay.
 

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So your saying its definitely the CDV and not the clutch thats at fault?
 

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JBgotM said:
I had that at the drag strip after I bought the car, shifting 2-3 and shifting 3-4 the clutch would slip down then catch. Then the clutch slipped once when I tried to spin in 1st and it spun the clutch ALOT. After that I just went and put in the aftermarket clutch and flywheel and it has caught hard everytime since and have ne no evidences of slipping or delay.
Your aftermarket clutch likely has more spring force and hence is probably less affected by constricted hydraulics when the plates are coming together.

I roasted my clutch twice at the last driving school in 1st to 2nd shifts at redline. Throttle lift, engage 2nd, let the clutch out and get back in the throttle, only to have my tach shoot up to the rev limiter and smell burning clutch in the cabin while watching my time go down the tubes. :)

Randy is on his 2nd clutch in the S54. I think the stock spring force is sufficient, but it's engaging slowly while pushing brake fluid. Saves the driveline while eating clutch. Fine for everyday driving, even semi-spirited driving, but at 10/10ths it seems to be an issue. I'll know soon; new line goes in this weekend and next driving school (same course) is on the 23rd.
 
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