I've never bought a clutch but I was reading this the other day so I thought I'd pass it on. Copied from UUC Motorwerks website:
How to choose a clutch
The selection of the correct clutch for the intended application is critical to good operation, including the characteristics of (but not limited to:
- clutch feel
- operating temperature range
- wear characteristics / durability
- clamping force
- break-in period
Quite often, the first impulse is to get "too much" clutch. This is often a very big mistake, as there will be compromises in some or all of the operational features listed above.
The first step in identifying what clutch to get is dependent on the characteristics of the car. Ask these questions:
- How much power does the car make?
- How is it used? Street driving or track use? If for racing, what kind of racing?
As we are dealing with BMW applications here, let's use an widely-understood example - the 1992-2004 6-cylinder 3-series. Over this 12 year period comprising two different chassis, we are still dealing with virtually the same fundamental engine and transmission designs. Power ranges from around 190hp to 333hp. Typical bolt-on modifications bring many of the early models up to the 215hp-260hp range and later models around 350hp. Extensive modifications including supercharging or turbocharging bring power to the 350hp-450hp range, with some examples in the 500hp-600hp range. The typical BMW enthusiast uses the car primarily for sporty street driving, and the occasional auto-x or track day. The 3-series is also popular as a heavily-tracked car and dedicated race car. Some see time spent drag racing, whether occasionally or as dedicated drag racers.
So it is apparent that we have a broad range of power and use to contend with.
Presented in increasing "aggressiveness", here is a brief overview of clutch compounds, their power handling, and other characteristics:
(note that hp figures are generalized, pressure plate clamping force and torque curves are additional factors)
organic CHARACTERISTICS Metal-fiber woven into "organic" (actually CF aramid with other materials), original-equipment style. Known for smooth engagement, long life, broad operating temperature, minimal-to-no break in period. Will take hard use, somewhat intolerant of repeated abuse (will overheat). Will return to almost full operational condition if overheated. Material is dark brown or black with visible metal fibers. USE Street-driven cars up to 400hp, auto-x and track use.
You can find the rest of the article
at their website. Click product catalog > then use the links on the left side to navigate to their section on performance clutches.