I said live with, not solve. :)

I am rarely (ie once per session) in first gear on the track. Just shift slightly slower. I never notice it in the other gears.

Do we know, absolutely and unequivocally, that the Subaru BRZ does in fact have a clutch delay valve?

I don't drive in such a way that it would be readily apparent; like you, Dave, I don't notice it on my S2000 (parked for the winter).

Has anyone posted or linked to, say, an exploded parts diagram that proves the Subaru has such a valve? Although, if you've disassembled yours and held the valve in your hand, Dave, I'd be inclined to believe you. I'm not denying it exists, I have no idea either way, merely asking for convincing evidence. If proof has been posted, could someone direct me to it, please? Until I see something like that, I'm skeptical.

Thanks.

x2

I do notice it myself but I learned quickly to drive around it. I have noticed that it not as noticeable since i took delivery of her. Never had that "feeling" with my other manual cars (supras, wife's miata and z24).

If there is no valve to speak of, then could it be the fact that our clutch does not directly drive the master cylinder? Could even be that there is a banjo setup on the slave cylinder (but I very highly doubt this is a cause). These two things I have never seen/experienced on a car before so I'm only speculating here.

my .02 fwiw :bonk:

Hmm good call. I notice that 1-2 and 2-1 shifts suck ass but that could be trans design more than anything else. It feels like a CDV because the symptom is similar to the clutch not being fully disengaged. I haven't tried to locate a CDV which is reportedly in the BMC. Subaru and many others are using these days so it just made sense but I certainly never confirmed it.

We need an informed and competent automotive drivetrain engineer in this thread.

Lowering the grab point of the clutch helps, and a smooth let out of the clutch (not a dump) works.

That, and a good heel-toe blip while clutching out, makes for some good spirited shifts.

If there's a CDV there, then I'm not yet good enough or fast enough to notice it yet.


@chrisl, do you go for Puma motorsport shoes, or just Puma shoes in general?

When it warms up in the next day or two, i'm going to check out the engine bay and look for things that are similar to a link that was reference earlier in this thread.

http://www.iwsti.com/forums/how-inst...post-pics.html


From what I remember I don't remember seeing a type of "container" or "proportioning valve" on the clutch system but again, I don't exactly remember and rather go check again.

DISengaged?

You meant not fully "ENgaged," right? A feeling as though the clutch isn't "biting" as crisply as it should? So, it might be difficult to abruptly break away the rear tires, for instance?

Otherwise, I'm confused ... which is a frequent state for me in my old age. ;)

I don't recall seeing anything topside. If the BRZ employs a clutch delay valve it might be located down around the bellhousing/clutch assembly. IIRC that's where the CDV is found on my S2000, and isn't that where the CDV is located on the STi?

I recall the S2000 needed one, not to protect the clutch, but because the differential was prone to breaking, so Honda employed a clutch delay valve to soften the driveline shock resulting from abrupt clutch engagement as drivers sought to deliberately break the rear tires loose.

It is 1.1* F here right now. Oi!

It'll be months before we experience warmth again. :)

My thought is that a well-timed, well-executed, smooth shift would MASK the presence of a clutch delay valve.

That's why I have not noticed any such valve ... 'cuz I'm so GOOD, don't ya know. :D

(I'm sorry; I'm weak and couldn't resist...)

You're not going crazy.

Oddly, this BRZ is one of THE most difficult cars to shift smoothly that we've ever driven.

You have a low post count, so I'm guessing you're new to this car. Smoothness will come in time, as it did for me. But, I'm still hard-pressed to define exactly what the issues are here.

I'm thinking the "awkwardness" of shifting, especially the 1-2 shift, is attributable to an odd clutch take-up and an awkward drive-by-wire throttle pickup. The throttle (as I recall) is sort of nothing-nothing-BAM more than I wanted sort of thing producing jerky shifts, rather than the smooth, SEAMLESS shifts that I strive for. I try to shift so that as a passenger you cannot tell that I've shifted, smoother than any automatic transmission. Quickly, too, but not faster than it "likes."

Now that I can shift seamlessly (after some time), all I can say is that I just "squeeeeze" the throttle and properly coordinate the clutch engagement such that my shifts are smooooth. I wish I could be more specific for you, but my body just "does it," now, and I cannot say exactly how. Kind of like walking on a tightrope; I don't fall off anymore, but I can't exactly describe WHY except to say that I kept practicing until I got it.

I realize this hasn't been much help, apart from reassuring you that you're not crazy. Keep working at it, and it will come in time.

Just do not slip your clutch too much; you'll wear it out prematurely.

We need an informed and competent automotive drivetrain engineer in this thread.

Depends on the shift. Sometimes it doesn't feel like it's disengaged (mine has ground gears on slow shifts with the pedal on the floor) and sometimes it feels like there's a delay in engagement. I only notice it in 2-1 and 1-2 shifts though so maybe it's just trans design.

This is completely true. I wasn't sure if I was just crazy, but every time I test drove a BRZ I would be surprised how far I had to push the pedal to get any throttle at all. It was quite the shock coming from my 06 Camry (which is also Drive-by-wire) where you can ease onto the pedal and start getting controlled throttle.