I have been researching clutches and dont see much about the stock clutch obviously most would upgrade because no one wants to do something two times, but I would like to know the following. I like the feel of the stock clutch but future goals my prevent its use.

Who makes the stock clutch?

What is the maximum power it will hold?

 

Sachs makes the stock clutch. I'm not positive on HP numbers, but If I was going to upgrade I think I would go with the 996 GT3 RS Light Weight Flywheel Conversion Kit. For more information Click Here.

 

Very well put together package! price is good too. One thing the crank pulley is also a under drive unit besides being lighter.

Tim

 

How much power is that GT3RS kit good for?

 

My info is the stock setup is good for around no more than a 10% increase in power/torque. This is just a rough number as how the car is driven plays a big role. If the owner/driver is dropping the hammer all the time and in other ways really putting it to the clutch the stock one won't hold up even with stock hp/torque.

Do this before you put on an under drive pulley. Get out a flat bottom sauce pan and put about an inch of cold water in it. Put the pan on the stove on medium heat and watch it until bubbles start to form on the bottom. Carefully move the pan about in a circular motion to swirl the water in the pan and note how the water's movement removes the bubbles.

Let the water get hotter. The bubbles get bigger. Now swirl the water around. Notice it takes more energetic movement of the pan to get the water moving with more speed/force to remove the bubbles?

If you run an under drive pulley the water pump doesn't circulate the coolant with as much force. It is possible this can have some of the hottest areas of the engine develop localized overheating as the bubbles from the heat do not get removed from the action of the coolant flowing by. All for the sake of an insignificant amount of hp "savings"...

 

I like my Sachs performance clutch set-up with their special GT2 disc.. Holds my 18g set-up and feels close to stock..

 

most of the reason for the underdrive pulleys is the mounting of the stock pulley is not very good and they have been seen to flyoff pretty easy. so i know the evoms and BBI unit are an underdrive of like 3% and lighter, with better mounting.

if you doing a 10-20% underdrive yes it would be something to think about.

 

which disc material does this kit use?
Organic/kevlar/fiber tuff ?

 

A GT3 RS one is the same size as the aftermarket ones, which I have with the belt and hardware from Porsche that I haven't put on yet. Might sell it cheap?

 

I'm about to put in a similar kit except I'm going with the improved 997GT3RS 4.0/GT2RS clutch disc instead of the older design 964RS disc. Porsche made improvements to the springs and rivets on the new disc and it should be more durable and a bit quieter than the 964 disc. I'm also using the 764 Sachs Motorsport pressure plate instead of the 996GT3 PP. The 764 has the highest clamp force of any of the Sachs Pressure plates and is a better fit for a torque rich Turbo car.

 

The clutch disc in the kit comes from Porsche, and I believe it uses an organic friction material.