The best organic facing is smoother than brass. However, many organics can exhibit "shuddering" especially in reverse when trying to slip them to back up a heavy trailer. The brass has a high coefficient of friction, and that is where its high holding power comes from. That also means it tries to hold (aka grab). If the truck is not moving, and you let out the clutch at around 800 rpm, it will shake the truck trying to get it moving and trying to grab because the flywheel is turning 800 rpm and the transmission input zero rpm. The easiest solution is (1) use first gear and just let it out--torque multiplication will take care of the rest; or (2) in 2nd gear, give the engine around 1000-1100 rpm so the clutch can't grab. The friction will start the truck rolling. As soon as that happens you can let out the clutch the whole way and the Cummins governor will take care of you. Either way is pretty smooth once you get the hang of it. The brass pucks have two major advantages: (1) great torque capacity; (2) won't fade or glaze. This type facing is used in almost all semi's and medium trucks. The drivers get used to them and they drive smoothly. A clutch should not be slipped much anyway; that is what wears it out, and puts hot spots on the flywheel and pressure plate.
If you are a one-time Bomber with medium power, say up to 300 or maybe 350 hp (800, possibly up to 900 ft lb), and don't have any idea of doing sled pulls, etc. where you have to slip it a good bit, organic is cheap, relatively smooth and easy to drive. This might correspond to someone who got a torque plate only, or just a box, or big injectors. Sometimes, folks with two of the above. If you want a clutch that will survive with further Bombing (might you be a bombaholic?) and will take whatever you dish out, you need the brass pucks. Let me clarify that torque not hp is what slips a clutch, but it is easier to refer to hp figures for some folks. Many don't realize that our Rams may produce 2. 5 or more ft lb for every 1 hp, depending on what "toys" they have fed their Rams. The Dynojet does not record the peak torque, and that compounds the problem with referencing torque figures. If you tow your heavy trailer and let the cruise control floor the pedal at 1600-1800 rpm pulling up a mountain, you can find that (a) the engine makes more torque than you thought, and (b) the clutch you thought was "enough" won't hold all of it.
I feel that the organic disk with the high pressure custom Sachs pressure plate is the best single plate organic disk clutch for high torque Rams. There is a lot of surface area to provide clamp and spread out heat, and the disk facing is very high quality. However, the picture of Bombing has changed. No longer do many folks feel that an uprate to 230 hp and 605 ft lb is "satisfying. " Even 280-300 hp and torque from 700-800 ft lb is "ho-hum" for many who consider themselves "reasonable" and "conservative" about power. Some "think" they are happy at 300 hp, and get a clutch that is adequate for that power level. Lo and behold, about 6 months or a year later, a set of humongous injectors (or another little box that slips under the dash so easily) beckons irresistibly. Whaaaat!!!! OOOHHHHHHHH NNNNOOOOOO.
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I'm sick. The clutch slips. AAAARRRRGGGGHHHHH. All I did was---,
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and now that junky clutch is toast.
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Yep, blame the poor clutch. Dodge did try to save $500 or more off the retail price by putting in a cost-accountant's dream clutch. Now you need an engineeer's dream clutch. If the modification is easy, like clipping onto a wire, or slipping in a part that "looks" the same as stock, surely the clutch should be able to take it. Nope.
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Hehehe. Such is Bombing. You just added 30-40 hp, but maybe 100-125 ft lb and it's time to put the power back on the table, or else admit you belong to Bombaholics Unanimous and get a "real" clutch and chase the power vs. clutch dilemma with the "real" Bombers. Rest assured the automatic transmissions are even worse off. What you can demo to folks as adequate for 280 hp becomes another story at 380 hp. 480 hp? You got a real dilemma there, hhmmm, better attend May Madness. We will have cutting-edge auto trans companies represented there, tech talks and roundtable discussions. Bombs away!
[This message has been edited by Joseph Donnelly (edited 01-06-2001). ]
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