CLUTCH 101
INTRO
The clutch is one of the most import component in a high performance build up. No other single component will be used as much by the driver and affect the way the driver interacts with his/her car.
This is posted in the FI forum because I have found this is where alot of members are dead serious about performance and engines found here make a shit load of torque.
MY BACKGROUND
My name is Robert Martin and I have been building Honda engines, trannies, doing swaps, etc. I also have been selling and installing clutches for the past 4 years. I have had the luck to be very good friends with Alex of Action clutch and because of this have seen many many clutches. Here are some things I would like to share with you so you can make a better decision on which clutch to run.
THE PLAYERS
In no particular order:
ACT
ClutchNet
ClutchMasters
RPS
Herson (HC Racing)
Action Clutch
Clutch Specialties
ANATOMY OF A CLUTCH SET UP
This diagram is far from complete but it will help you see what's going on.
Basically the clutch locks the disc onto the flywheel using the diaphram as the loading mechanism. When you push in the diaphram it lifts the FRICTION RING and the CLUTCH DISC is free to spin independantly from the engine so you can change gears without grinding.
Any flex the CLUTCH COVER will hinder the FRICTION RING from releasing the CLUTCH DISC. Currently the only company to offer their own custom CLUTCH COVER (that is affordable) is ACT although OEM FCC or Exedy CLUTCH COVER's work fine.
As you can see if you move the LEVER POINT's closer to the PIVOT POINT the DIAPHRAM will have more leverage and exert more force on the FRICTION RING.
ACT, Clutchmaster, Action, and Hersons do this by machining the LEVER POINT so that the peak of the LEVER POINT is closer to the PIVOT POINT. The side affect of doing this is that it requires you to push on the DIAPHRAM further than you would if the LEVER POINT was not moved. Clutchmasters does a unique thing in that the place spot welds to build up the LEVER POINT's and then do machining to be be able to move the LEVER POINT the furthest.
Another way to increase pressure is to install a stiffer DIAPHRAM. ACT, Action, and maybe RPS does this (I have never seen RPS since they are not popular in LA). ACT has an extra thick 3mm vs. 1.8mm DIAPHRAM that they use in there Extreme pressure plates. This gives good pressure but is on the thick side and has been known to crack due to it's thickness and the hardness of the steel that it is made of. It's very hard steel. It has the highest hardness of any diaphram I've seen.
You can also install another diaphram and have two diaphrams. This is what is called a DUAL DIAPHRAM clutch. Herson, Action, ClutchNet, ClutchSpecialties, and some smaller shops make these. Note: to properly make a double diaphram clutch is not as easy as slapping in another Diaphram. The rivets holding in the DIAPHRAMs must be longer, the FRICTION RING or LEVER POINTS have to be clearanced to make room for the extra DIPHRAM. The only companies I know of that can do this properly is Action and Hersons.
CLUTCH 101...continued
What's the Best Disc?
The answer is which ever one will work properly for your application at the right price.
Here is the best stock disc. It's a Exedy "Unity" disc and incorporates some nice features like forged spring retaining plate(purple) and decently strong springs.
Here is an aftermarket sprung six puck. This particular disc is used by Action, Hersons, Clutch Specialties, and RPS(from what I can see from the pics of there website).
If you compare the features of this disc with the Exedy you'll notice it's held together with 6 rivets rather than the 4 that hold the Exedy together. Also notice that the springs are much shorter .
Here's an aftermarket full face sprung disc with kevlar facing. The kevlar lining will literally last forever. I am not exagerating here. We have many customers coming back to fix their clutches but the kevlar lining just needs to be sand blasted after that there's no way to even tell that it's been used.
Kevlar is also so easy on the flywheel and pressure plates that you can still see the machining marks on the friction surfaces of the flywheel and pressure plates after years of use.
Here is an aftermarket solid six puck used by Action, Clutch Specialties, and Hersons. This is what I consider the standard of disc and works really well in performance applications since it is light and will be easy on your tranny when it comes to shifting. With the Miba friction pads it's also possible to engage chatter free but engagement will be much faster than stock organic.
Here is the baddest of the bad dogs. It's commonly called the "Iron Disc" and is made by Raybestos and used in truck applications and also used in twin disc apps on Ram Clutches in NHRA Pro-Stock cars. This is used in Clutchmasters, Action's and Hersons most heavy duty clutches. This disc needs alot of pressue to work properly since it's a full face and has a lot of surface area.
Clutch 101 By Rocket
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Originally Posted by vteckidd
