Diaphragm vs. Borg and Beck.............

You know what? I learned a long time ago that it is easier to throw an error out there ands make it sound correct than it is to dispel the error. It would take pages and pages and pages to correct just part of what weed burner claims. He likes to slip a clutch. Stop and think about that for a bit and let it sink in.

Way back in the day, I had a buddy with a tunnel rammed camaro and a 4 speed. He ended up with an adjustable pressure plate and a rag disc. The car went, like 4-5 tents quicker than what he had before, which was a bronze puck clutch and the dubious birth control pressure plate. I can't remember how many GM boxes he killed but it was plenty. Then he converted it to a Top Loader. I voted for an 833 but the bow tie snivelers over ruled me. Did have my buddy put an 833 in his car btw. Anyhoo, it just took longer for the TL to fail than the Muncie. So he went to the adjustable Long pp and a rag disc and the car went faster. He would replace the disc every 90-100 runs and keep going. Went faster. Never broke ****. But he had to learn to do it. A sintered iron disc (Sof-Lok because that is what most people recognize) will allow even less base pressure, and base pressure kills parts and makes you slow. Plus the the sintered iron discs last longer. Unless you use construction parts to make it slip rather than using controlled lock up.

Let's take your car as an example jpar. Please note, I have a fiddle recital to go to in a bit, and I am using some of my car time to type this long, drawn out ordeal.

So, using you as a LEARNING example, I watched a couple of vids you posted and PM'd you my thoughts. IIRC, they were passes earlier this year. I said you need double adjustable shocks front and read. Because you run a stick, you can't get by with what the slush box pussies do (no offense to those of you of that persuasion). You need to control the motion of the springs with the shocks.

You need to SLOW EVERYTHING DOWN. I can't remember if you have an aluminum FW, but it would help if you do, and I'll tell you why in a bit. Everything about a clutch car is control. Controlling engine speed. Controlling clutch lock up (not slipping it) is a big, big deal. Controlling your suspension so you don't beat the rear tire to death, and controlling longitudinal load transfer so you don't hit the limiters and shock the rear tires into spin. It's all about control. No other couch system, and the level we are discussing will do anything near what a sintered iron set up will do. You have to be willing to get it all correct, and test, but you will be faster every time with an adjustable SI clutch.


Let's talk about plate load and when you get it. I don't post pictures, graphs and stuff like that. We don't need it now. Plus I never put my images on the web. I have had my technology, and even my exact words stolen from me, with out due credit, let alone proper compensation. So I don't post pictures of plugs and how to read them, or correct rocker geometry or stuff like that. I do give out some knowledge for free. But I ain't spent my entire LIFETIME learning internal combustion engines and tuning etc to give it away for free. I still get paid to do some of this. Ok, hope that clears that up and we can discuss plate load.

Plate load consists of two primary things. Static, or base pressure and counter weight, if any. All clutch levers, including the birth control style (come on, you all know that's funny as hell when I do that so just chuckle and move on) will have SOME effect of counter weight. Base pressure comes from the number of springs in the cover, the spring rate of said springs and the installed height of the spring. Sound familiar??? It should. No different really than a valve spring. Borg&Beck's have 12 (TWELVE!!!!!!!!!!!!!!!!!!!!!!!) coil springs. That's a ***** right there. The Long has only 6! When you are young, more is always better. This is a case of where it isn't so. The BB/Long cover (which I currently use) has 12 springs in it but has adjustable spring seats in it.

So plate load is a combination of spring rate, number of springs and installed height. Typically, B&B's usually are somewhere between 2600 pounds of base to about 3500, but I have personally seen some that were over 4000 pounds. It would break a Dana like a match stick, and it's stupid. You can get the B&B with no roller, 3 roller or even 6 roller assist, and it ain't adjustable!!!!!!!! Think of that. Just sitting there, you have 3000 pounds of base. Start the thing, and even with just 3 rollers, you start adding base pressure even at idle. Turn it 6K and now you are probably adding another 1000 pounds at a minimum to your total plate load. No wonder guys break parts. Some guys fix this by slipping the clutch so it don't hit as hard. That is bad.

Let's add another dimension into the equation. My favorite thing in all of motorsports...RPM. RPM can be your friend, or Satan. For most of us its satan. When a clutch car is sitting on the starting line, the pedal is down and the engine is just singing away. Now you drop the hammer and ALL that stored energy is dumped into the drive train. And then, usually parts dump onto the track. Unless you get lucky and bake the hides. This is the fine line where control comes in. You want to beat the tire as hard as it can take, with out whipping is butt. RPM is a huge factor that gets over looked. Overlooked both in terms of what I cal HIT and its effects on counter weight assist. Think about that for a bit.

Now we need to discuss discs, and disc material and construction. I want a disc as light as possible. Sometimes you have to accept the weight to get a disc that won't break your parts. Here are 2 simple examples. A sintered iron disc, with a riveted hub is much heavier that a rag disc, even if th rag disc has a spring hub. That is bad. Now look at the lightest disc I have ever seen, IN THE PARAMETERS WE ARE DISCUSSING HERE. That disc is the famous (infamous????!!!!!!?????!!!!) Ram 3 puck bronze puck disc. I can say it is the lightest disc I have ever found. That it all I can about it. It is JUNK. It has maybe one, maybe, use in life and that is some form of a circle track clutch. Other than that, it's 100% garbage. I'm not banging on Ram or its products. Back when I was starting this, Chrysler clutch options were limited. It was essentially Ram and McLeod. I was burned on McLeod by a parts counter guy who was, and if he's still alive, is as full of **** as an Xmas goose. So I had a bad taste in my mouth from about 1980 until 1997 until I pulled my head out of my prostate region and actually called and demanded a clutch that would function. Disc weight makes what I call power shifting possible. The lighter the disc, the easier they shift. A heavy disc just won't shift under load, at RPM. To compensate for heavy discs, slick shifting, pro shifting, lugs and dog ring type engagement were all invented. They all work in some capacity. The reason I mention this is because, it is all a system.

Time for a break. Later tonight, we'll get into the coefficient of friction of disc materials and why HIGH coefficient of friction discs are preferable to lower CF discs, and why this even matters, and how it affects, and effects, clutch management.

Hope some of this makes sense. If it don't, keep reading. I will tie it altogether at some point and maybe, just maybe, it will become less ambiguous as to why I detest a birth control pressure plate and discs other than sintered iron, except in cases of dead stock stuff. Then I would recommend a B&B with the correct pressure rather than a birth control PP. correct pressure depending on all th parameters will will discuss.


This will be long. It has to be. An old lady, who was dead by 1914 said we have much to learn, and much, much more to unlearn. Such is the case with clutches.

I'm off to fiddle fest.

Later
Yr.