i was just warming up for a 23 psi 3rd gear run as it is a glorious 66 degree day here in wisconsin, maybe the last of the year...

previously i had been out last week on the same stretch at 48 degrees and the car just went sideways at 3.6 on the 4.6 TPS voltage scale at around 17 psi. sideways at 79 mph. lots of power. cool.

so i dropped my rears another 2 psi to 25 pounds (285/30/18 Toyo TS1s) hoping to pick up some grip especially combined w the warmer road surface.

i guess i did as at 18.7 psi 5600 rpm the rpms took off leaving the car behind.

alcohol is going to change many of the system parameters we run on our cars.

in the case of clutches, even if you are running pump, you'd better load up.

i'd be buying stock in twin discs and carbon...

howard coleman

 

Howard -

thats good to hear. . .kind of

are you still running the stock transmission and rear end?

thanks
ryan

 

I’m in much the same boat as you are right now because I smoked an ACT extreme clutch combo. Actually I’m kind of fooked because I hate clutch chatter, I mean I utterly despise it in a street car. And as I understand it all, the puck and twin disk set ups all chatter like crazy. So I don’t know what I am going to do when I smoke this one.

Good luck, report back what you think of twins on the street.

 

i am running a stock trans w a short 5th gear and the rear at present is stock. i have a T2 LSD for it that i will install over the winter. i do not drag race so i may not need uprated axles. i will be doing a bunch of track days next year at Road America and various other tracks and may do the Silver State Classic.

i really loved the Exedy package and will probably upgrade to the Dcore double. if it is properly broken in it is bullet proof and doesn't chatter. Rice has alot of experience (apparently all good) with it.

howard coleman

 

I love this kind of update, but sad to hear you have to tear the car down again...

good work!!

 

Yep, love the clutch very much howard

Hopefully will get to test it to its full capacity soon once my turbo's come from BNR soon

 

Hey,

Where are you guys buying the dcore clutches? I've been looking around on the internet and they seem hard to find.

- Andy

 

You need to look into a twin disc carbon/carbon clutch setup.

 

lol someone has to make these carbon series clutches more affordable!!

 

after removing my clutch and inspecting it, it looks like new. so it wasn't a case of the lining coming off the disc and there is absolutely no sign of overheat, it just didn't hold the torque.

i am going to measure the disc thickness and compare it to new as it is my opinion that it shows virtually no wear after 10,000 miles of (easy---no drag race stuff) usage.


i really liked the drivability of the cerametallic. just the right amount of slip and it held til it didn't. i may just buy the cerametallic double. it holds a hair more torque than the twin carbon. around 600 to 700 ft pounds at the flywheel.

BTW, an interesting metric w regard to twin disc v single disc clutches is their softer pedal. this is because since you have more frictional area you need less clamping force. for instance the Hyper Single is 2655 and the double is 2205. Exedy uses a different than stock leverage so the Hyper Single seemed just fine as to pedal pressure...

the best shipped price on the double cerametallic i have found (thanks Rice) is $1316 and the D-core is $1808. speaking for myself the difference is not enough to disqualify the carbon but i do like the cerametallic.

the only non-Exedy clutch i am considering is the Carbonetic twin carbon.

howard coleman

 

So the cerametallic exedy twin pate clutch holds alittle bit more torque compared to the more expensive carbon twin plate? I've been saving up for the exedy twin plate cerametallic version I'm almost there! I had the chance to buy a mazdaspeed twin plate for $500 barely used, but someone beat me to it on ebay. Looks like exedy made the twin plate for mazdaspeed...

Jay7..

 

I have the same thing on mine howard it's not the plates themselves that are worn why it's slipping it's the pressure plate that can't hold torque.
I'm gonn put my slipping hks twin plate in another car it will be fine with less power/torque going through it. I made up my mind on the spec stage 3+
it should be up to the job.

 

Jay7:

as per Exedy's published specs...

the friction coefficient of their patented cerametallic material is .49 to .47

the friction coefficient of Exedy carbon is .31 to .48 depending on how hot it is. i have heard reports of carbon slippage, maybe due to not being hot enough. the driveability is excellent as it can be slipped cold. Rice thinks the Exedy carbon is superior to all but Tilton. what i don't know is how it would hold 630 rear wheel hp which is my target.

the two other factors are disc weight and longevity. the carbon wins both.
40% less disc weight and supposedly 2.3 times the life. the US Exedy guy ( Kevin Fujioka, head Tech USA) said that the test did not account for the attendant wear from having to warm the carbon clutch up so it would hold the max and when you factor that in the difference is not that great. as to disc weight i have not heard one complaint about the twin cerametallic hanging up on high rpm shifts.

then there's the Carbonetic twin... and maybe the spec 3+... supposedly it holds 595 flywheel torque and is a single disc.

i sure wish we had more usage reports.

anyone out there?

still noodling on clutches.

howard coleman