GQM

Does anyone know where the CDV is in the hydraulic path? This is the valve the causes the fluid from the slave to return slower essentially slipping the clutch a little when getting moving as well as in between shifting gears. I think they do this to prevent shocking the drivetrain as much, but I find them terribly annoying to drive with and in the RX-8 you can absolutely feel the delay for RPMs to drop in between shifts.

Some cars they can be removed somewhere in the hydraulic line path like on BMWs. They introduced this on the Ap2 S2000 in the slave itself. You could either drill it out or just install an AP1 slave cylinder to remove it, etc. In most cases they can be eliminated. I couldn't find anything on the forum here. I just need to know where it's located first

Thank you in advance!

Brettus

iTrader: (2)

Never heard of nor seen such a thing on an 8.............

Loki

iTrader: (1)

Uh sir you can't just make up valves. I know what you mean about rpm hang, but that's just the engine having less internal drag and pumping loss than what you're used to

TeamRX8

iTrader: (25)

on an RX8 it’s only used with racing type clutches (7.25” or smaller) to slow the engagement for a smoother standing-start launch and minimize drivetrain shock. Alternatively the hydraulic slave and/or master sizes can be adjusted to accomplish the same thing.

https://tiltonracing.com/product/flow-control-valve/

it has no place on the usual RX8 street clutches imo. Your
engine is likely suffering the usual Renesis fate or your clutch has issues. To the best of my understanding, the factory system doesn’t have one. Nor does it even need one.

I drop launched the factory clutch 100”s of times without issue at 7000+ rpms over many years of SCCA pro solo event competitions that use a drag type xmas tree startt system with two cars simultaneously launching and running mirror image courses at the same time against each other. Not claiming there’s not an issue, just that you’re barking up the wrong tree.

to wit, I also broke 6 or 7 manual 6-spd transmissions over that same period, every one of them shifting hard into 2nd gear from those launches, which spins off all the countershaft teeth. If anything, it’s an argument to install one rather than to remove one. The difference is that was with very high grip tires and slamming gears in a manner not usually to occur on any street car.
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spectre6000

Try a lightened flywheel maybe?

GQM

I guess it must just be the weight of the stock flywheel then. I have a 12 lb unit on my FD, which is not much lighter than the OEM RX-8 wheel if I'm not mistaken and it doesn't have any of the hang I feel like I experience with the RX-8. I was pretty convinced it had the clutch delay valve since most manufacturers started introducing them around the 2003 time frame. I run 7lb flywheels on my AP1 S2000 and all motor ITB Miata and they are still very streetable with a full disc clutch (non-puck), sprung and unsprung respectively.

Has anyone run a less than 9lb flywheel on the 8 with a OE sprung clutch assembly? If so, how was the drive-ability?

TeamRX8

iTrader: (25)

why would you ask rather than search 20 years of resource? 🤔

it’s a facetious Q though … so here you go, the Racing Beat aluminum flywheel is supposedly 8 lbs (their claim, I never weighed one) and there are reviews all over this forum. The OE flywheel is approx. 17 lbs.

I know where a used one can be purchased with a new replaceable wear insert installed if you’re interested. Probably the auto counterweight too that adds several pounds. With the weight of an OE style clutch (~17 lbs) it should be fine. Which I’m sure you already that RB is not the type of company to push limits on their general vehicle products.

Now imagine if your entire mounted clutch/flywheel assembly weighed less than 9 lbs , then you need a clutch delay valve.
.

GQM

I get it, I wasn't trying to be lazy here. I have searched and read previous posts, but most folks run their stuff with aftermarket clutch's and pressure plates. I like the OEM components if they can be used. Like I mentioned I have a N/A AP1 S2000 build using a Fidanza 7lb flywheel, with OEM Exedy Clutch and PP. I also have a Fluidampr harmonic balancer which shaved another 1.3 lbs off the rotating assembly over the factory unit. So the entire rotating is extremely light. Most OE PPs are lighter than aftermarket units with the exception of the Spec PP I used in my built N/A Miata (which also has a 7lb Fidanza, lightened harmonic balancer and PP but with an unsprung stg 1 full disc but is still easy to drive). Was there a little adjustment required in my around town driving to shift a little faster and to be smooth with my clutch foot? Of course, but it's nothing that I would say is a nuisance and I'm getting to the point where I am more old man, get off my lawn and do not want to mess around with an annoying car on the street. Again, I think most people **** and moan about light flywheels when combined with unsprung puck clutches given their grabby nature. So that is where the question was aimed at experience with a really light flywheel and an OE or mild clutch setup.

Which flywheel do you have and what is the weight of it?

motodenta

Its integrated into the master and/or slave cylinder itself, on some designs it is part of the hose.
I haven't had time to study those sections yet, but if some can share the cutaway I can have a look.