Clutch damper/delay valve

[roarf]

Who here has deleted their clutch damper/delay valve? Those who have deleted it, what was your reason(s) for doing so and what differences did you notice afterwards? 

I am considering deleting mine. Based on previous experiences with cars that had them (BMW), it was only a positive thing to remove it. Two main reasons I am now considering this on my Evora.

1) High rpm shifts (at or very close to redline) are often times not smooth. 2nd to 3rd and 3rd to 4th in particular (I rarely do this from 1-2). I have missed the 3-4 shift completely a couple of times or even got a slight grind and I know I had the clutch fully depressed when I shifted. Very annoying, slightly dangerous.
2) For the first few shifts into 2nd when the car is completely cold and fluids haven't warmed up yet I have to shift very slowly into 2nd or I get a slight grind. Not uncommon to need to slow it down when the trans in cold in most cars, but I find it a little excessive in this car for some reason. Wondering if the clutch damper exacerbates things when the clutch fluid is still cold.

I realize worn engine mounts and poorly adjusted shift cables could be a factor in these issues as well but my car shifts very smoothly 95% of the time and the shifter has a nice positive feel to it, no vagueness. I don't shift at redline that often but when I do I want to know that I'm not going to miss or grind. I am not power shifting or slamming gears here. A reasonably quick, smooth shift is all I'm looking for. The revs drop pretty quick with the lightweight single mass flywheel so I want to match the revs as closely as I can.

And yes, my brake/clutch fluid is fresh. I change it once a year with Motul RBF600. Pedal feel is firm and smooth. Never had it get soft in the 2.5 yrs I've owned it. Trans fluid is Redline MTL 75w80, changed 1.5 yrs ago.

Any feedback/help is appreciated.

[Bravo73]

Hello roarf,

Welcome to TLF. 👋

I can remember clutch delay valves being an issue on M3s (e36, IIRC). However, I can’t recall anyone ever having any issues with the Toyota/Lotus setup. I certainly don’t remember any discussions about owners removing them. (I’ve personally never had any issues with clutch engagement, either on the road or on the track).

What sort of feedback having you been getting over on LotusTalk? Have other US owners been removing them?

[Bruss]

A solution looking for a problem?

Not heard any at all problems with a cdv on the Evora.

 

Shifting is dependent on the things you mention but the main one in my experience is the cable adjustment at the gearbox end. Cables stretch and every time a service is due the cable should be adjusted to keep that tautness  and positioning accuracy. 

Other things help such as fresh oil and keeping the oil at the right operating temperature. Newer cars and I think all auto versions have a gearbox oil cooler fitted to help.

[roarf]

8 hours ago, Bravo73 said:

Hello roarf,

Welcome to TLF. 👋

I can remember clutch delay valves being an issue on M3s (e36, IIRC). However, I can’t recall anyone ever having any issues with the Toyota/Lotus setup. I certainly don’t remember any discussions about owners removing them. (I’ve personally never had any issues with clutch engagement, either on the road or on the track).

What sort of feedback having you been getting over on LotusTalk? Have other US owners been removing them?

Thank you.  I didn't get much feedback on LT, only one person spoke up about doing this.  However, these are only present on MY12 and newer Evoras.  There is also only one vendor that sells the line to delete it (InoKinetic).  Kind of surprised BOE or MWR doesn't sell one.  I'd be curious to see one of these clutch dampers cut in half to see what's inside.  Is it actually restricting flow, or does it use some sort of diaphragm to dampen pulses/vibration in the clutch fluid, etc.  On a BMW, it is restrictive, but it literally is just an inline fitting with an orifice/flow restrictor (a hole much smaller than the ID of the clutch hose).  Even so, on my E46 M3 I never had high rpm mis-shift/grinding issues with the delay valve in place.  Removing it just helped clutch engagement feel/predictability.

 

7 hours ago, Bruss said:

A solution looking for a problem?

Not heard any at all problems with a cdv on the Evora.

 

Shifting is dependent on the things you mention but the main one in my experience is the cable adjustment at the gearbox end. Cables stretch and every time a service is due the cable should be adjusted to keep that tautness  and positioning accuracy. 

Other things help such as fresh oil and keeping the oil at the right operating temperature. Newer cars and I think all auto versions have a gearbox oil cooler fitted to help.

 

You are probably right.  It may just be a matter of cable adjustment.  Even with the gearbox fluid nice and warm I still get the high rpm grind/mis-shift if I don't slow it down a bit.  As I said, my car shifts smoothly the other 95% of the time, but I will definitely have the cable adjustment checked next time I take it in for service.  

[JAWS]

If you're pushing to slot the next gear above 6500rpm then the gearbox will baulk. You'd be better off putting in a lighter flywheel to let the revs drop quicker than mess with the clutch damper as it's not the issue. Especially as not one person has done this or made that adjustment. No point in wasting your time.

Alignment of cables, fresh oil and not being ham fisted is the key.😃

 

[roarf]

18 hours ago, JAWS said:

If you're pushing to slot the next gear above 6500rpm then the gearbox will baulk. You'd be better off putting in a lighter flywheel to let the revs drop quicker than mess with the clutch damper as it's not the issue. Especially as not one person has done this or made that adjustment. No point in wasting your time.

Alignment of cables, fresh oil and not being ham fisted is the key.😃

 

The stock S1 S flywheel is already pretty light (17 lbs?).  Not sure I'd want a lighter one, it revs up and down pretty fast as is.  The ECU tuning can have an effect on that as well.  I can assure you I'm not ham fisting it, that is not my driving style.  I have more mechanical sympathy than most people, maybe too much sometimes.  I can try slowing my shifts down, I am already used to that from driving cars w/ heavy dual mass flywheels (E39 M5, B7 RS4).  It just seems counterintuitive on a car that revs so freely.

[Bruss]

It is the Lotus way, unfortunately. Cables shifts on these are first, neutral, second, neutral, third, etc.

Never first, second, third.  Even more important on the way back down the box. Think Grand Tourer not track car.

The good thing with the S is that shifting isn't as necessary, even on track. I find rolling in at speed with a higher gear and then picking up the throttle earlier can work well.