Bacon

iTrader: (12)

THis is the second ACT pressure plate I've seen blow up in less than a year!
Last one was 100% act disk and pp
This one act pp RAM disk
This one I personally installed and torqued the bolts so I know install to specs
Scatter shields in place and both drivers without injuries
The stock style PP is garbage at these hp levels
Need a real clutch like exedy/clutchmaster 850
One that has 6 points of power transfer not 3 metal bands


Walking is way more important than your ego or budget stay safe fellas!

jdr821

iTrader: (1)

Wow scary for sure...

Howard Coleman

iTrader: (6)

thanks for sharing... your comments about walking should catch some attention. i will be doing a scattershield in the next 3 weeks and felt pretty naked withour one last Oct at the Texas Mile.

what were the exact circumstances when each failed?

i run a Quartermaster double disc w my T56.

serious stuff here... more details pls.

howard

diabolical1

iTrader: (3)

yes. would like to hear some details of the engine's capabilities and the circumstances. i'm very interested as well.

Bacon

iTrader: (12)

Both bigger hp cars, 660 and the other 685
Methanol
Happened to both shifting into third

One clutch less and one on a factory Fd box

Bacon

iTrader: (12)

So non Neanderthal response
Both of the cars were drag cars, one with 9"rear and a gf5r, act fw,disk, and pp (one with red scatter shield) this one was more violent as it happened at about 9k on the shift actually ripped the 1 piece scatter shield almost apart at the worst spot, dented the tunnel/firewall

Second happened Friday night, methanol powered Fd, stock trans but 8.8 irs.. Came apart after shifted into 3rd, split the goopy 2 piece scatter shield and you see what's left, data log shows it let go around 6800 rpm

Everyone Look at the stock style PP

ALL and I do mean ALL the force is transferred through those 3 little metal bands, so no mater the disk, the extreme or stage 55 it's all going through those 3 metal bands...

If it's breaking 1/4 steel imagine what it would so if we didn't follow all safety serious, sure it's not gonna happen to many of us but seeing 2 happen has me getting the credit card out and changing clutches

Imagine going to race on a Friday night and Saturday having to figure out how to live without a foot or a leg ugh!

Howard Coleman

iTrader: (6)

this thread s/b required reading

Copeland

iTrader: (42)

Thanks for sharing, glad to hear no one was hurt.

I bet Goopy gets a few extra calls now...

jetlude

iTrader: (9)

Is a scatter sheild needed for a 500rwhp street driven FD, limited to 8500rpm?

Bacon

iTrader: (12)

Stock fw?

Honestly a week ago I woulda said your fine now I don't know what to say.
I mean I'm making 820-830 through the exact same disk (2565lbs and 160 trap speed) and I haven't had a failure nor thousands of other high hp fd's
I do know that this year last years pressure place wouldn't line up all 3 dowels, on the streetlite fw only 2 at any configuration, starting to believe it's begins twisting then eventually let's go, and this year is a brand new pp
I'm gonna be moving over to a liberty trans in a week or so so i will let you know if this one bent

Some times saftey products you have to think what "could" happen...I hate the /15 sfi fire suit, but I bet if that methanol ever came into passenger cabin id be glad I had the $1200 suit, pissed I didn't buy the fire bottle, but still glad I had the saftey equipment

So I guess it's just are you a "what if" kinda person

Howard Coleman

iTrader: (6)

it is only a matter of time before someone loses all or part of a leg.

Daikin is one of THE global driveline companies... the stock FD clutch is a Daikin, the ACT pressure plate is a modified Daikin. yellow paint and stiffer springs.

the OE pressure plate was designed for 255 FWHP. just like the OE apex seals (2 piece) were designed to work at 255 so was the pressure plate. both are a mismatch at much higher power output levels.

because our motors are only 13 X 13 X 13 inches our flywheels are relatively small.

small flywheel = small frictional surface = high spring pressure needed.

so add the high(er) spring pressure to a OE clutch cover and it gets dicey. especially when our motors can make so much power for their flywheel size.

an OE clutch cover operating way past the design power level is a recipe for... well just look carefully at the pics in post one.

besides some sort of scat shield another option to increase safety is a double disc clutch. if you are running a stock trans Exedy makes a beauty.

double discs of course double the frictional area so they don't have to run 2600 pound springs. they are purpose built for the app.

Exedy is the R&D arm of Daikin and as such has virtually unlimited resources and it shows.

getting back to the safety issue... the stock PP and ACT variation have three metal straps holding things together. yikes.

double discs do not have the weeny straps. note the Exedy flywheel has 6 beefy supports doing what the 3 metal straps do...






when i swapped in a T56 gearbox i was unable to use my Exedy double disc. no problem, i called Quarter Master whose clutches i had run when i was racing. they do NASCAR and pretty much everything and are like Tilton... no "high performance" stuff. real race product. fortunately QM is close (Chicago area) so i was able to do facetime w them.

i ended up using their "Rally" double disc which is not on their website. it has 18% more frictional surface than my Exedy. we went for 2250 pound spring pressure. spring pressure is available in just about any amount you want.

i have run it for 4 years and the slider plate does not need to be replaced... pretty good. around the 550/575 level.

getting again back to the safety issue, note as similar to the Exedy, that 6 support posts that replace the 3 stamped steel straps.

double discs allow for a lighter pedal as well as they eliminate the questionable take-up straps.








howard

Rxmfn7

iTrader: (4)

Can someone explain how exactly it is that horsepower effects the clutch/PP/flywheel in a way that would lead it to warp and come apart? Does it just have to do with the clutch slipping and creating heat? I suppose Im just having a hard time understanding how a clutch will be more likely to explide on an 800HP car as opposed to a 400HP car, all else being equal. Clamping forces being the same the only thing I can think of in that area being different is the clutch slipping at the higher HP level.
On a side note I am running a similar QM clutch as howard had posted above, only it is a 7.25" triple disc. I was thinking that because of the smaller diameter and race quality I shouldnt have to worry about things coming apart, but those pictures are pretty scary.

papiogxl

iTrader: (6)

Think of it as half of the torque output to the trans from the engine is on the pressure plate side.

This scares me since I have an ACT FC clutch setup in my car with a torquey 2.8 VR6 that makes around 500hp with almost the same torque number. I've already been on the edge of switching to a TH400, and this very well may push me over.

weeters

i was just at import faceoff at the Lebanon{Albany,ny) race 2 weekends ago and an rx7 pressure plate let go. cut off an arm and half his face and the fireball burned 4 guys. this was in the pits. I thought I was back in Somalia with all the shrapnel. Blood everywhere. Please use scatter shields. Best 400 bucks spent.

rotorholic

iTrader: (53)

WOW, Sounds horrific

To the OP:

I wouldn't blame the ACT pressure plate, its up to the owner/racer to use the correct parts for the power they're making, I had a Jerico clutch-less tail housing explode on me during a burnout before, It destroyed my tunnel and left my leg bruised up, Why? Because I decided to use a heavy duty automotive yoke when building my drive-shaft (so I thought) I switched to Mark Williams yoke after that experience.

MR.45

iTrader: (1)

scary stuff. These scatter shields apparently aren't that easy to find on the net. Can anyone recommend a good shield with a "buy it now" button next to it... Id like to keep my legs.

ArmyOfOne

iTrader: (12)

Thanks for sharing Bacon! I installed a Scatter shield this year but I do have the ACT HDPP installed. I have worked too hard on this car and spent way too much money to just go out there and risk hurting myself, innocent bystanders and other racers if and when the pressure plate lets go and I lose control of the car.

I have seen and heard of this happening way too often this year.

Protect yourselves guys and gals.

MR.45

iTrader: (1)

This thread has me looking at rich man clutches now.. =( fml is it really that time to slam 2k+ on a clutch setup... ive been tryin to avoid this for years now Len got me shittin bricks. lol

rotorholic

iTrader: (53)

I have a T2 SS that is for my project but will sell it for now. PM'd

weeters

there's a shop in florida that sells them on ebay for 300. Type rx7 scattershield and it comes up.

smg944

iTrader: (34)

wow im on this same clutch setup will be changing that as well as add in the scatter sheild. bacon what clutch are you looking into? i hear only the carbonetics triple can hold power and not break Fd trannys. its a spring loaded center.

MR.45

iTrader: (1)

thanks, I can find scatter shields for T2 for days on the net. 3rd gen bell housings seem to be a bit harder to find.. Decided to either make one myself or just throw some kevlar around it.

MR.45

iTrader: (1)

call me a cheapass but aren't those triples over $3500...? fck me sideways for that kind of money im throwing a Lenco in the car and ditching the stock box. I would love to have a triple setup but that kind of money for a clutch is just crazy to me.

sk8world

iTrader: (5)

goopy has the scatter shields

http://*************.com/rotary_foru...ad.php?t=14846

sk8world

iTrader: (5)

http://r o t a r ycarclub.com/rotary_forum/showthread.php?t=14846

take the spacesaway. wouldn't let me post the link.