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914World.com _ 914World Garage _ New V8 conversion question: 8" or 9"

Posted by: Dr. Roger May 8 2005, 10:06 PM

This car will ultimately be AX'd and using a Otto-built 901 tranny w/911 axles and wide rubber.

My comcern is when using 2nd gear for first all of the time, won't I need the extra clutch area even more than usual?

Won't I wear out a 8" too quickly?

Posted by: messix May 8 2005, 10:21 PM

naw. second gear is as low has most trannies used for v8s and the car weigh so little the clutch wont see that much stress.... unless you slip it, ride it.

Posted by: Andyrew May 8 2005, 10:26 PM

What do you have to budget?

My 8in is not my weekpoint....

I'll put it that way.....

cv's, then suspention points, then trailing arms, then clutch (depending on the clutch), then trani....

Thats the weekpoints of the v8 901 cars. IN order.

Having the clutch slip a little bit once in a while, while keeping the 901 intact... Or having the 901 go out first is something to keep in mind...
I'd rather have my clutch go out...

At less than 100 bucks a clutch new... Im cool....

btw, never "launch" the car... If you have the rubber to grab it, you will blow your trani/cv's. Personally, every time I get on the gas in 2nd, the rear lets loose, unless im going perfectly straight, and im not in the powerband.

Andrew

Posted by: neo914-6 May 9 2005, 01:26 AM

8" is standard VW and readily available.

KEP can make a double disc 8" that they use for high hp/tq applications. I think Rod had another type too.

9" is the largest size for Porsche tranny's. Don't know the cost differential with 8" but I know it is more. Apparently they don't need the clutch extender as used on 8".

Andrew's points are good. What's cheaper to repair (in 914/901type) applications? CV/axles vs. tranny removal/clutch replacement vs.tranny removal/rebuild. Trailing arm stress?

Posted by: Paul Illick May 9 2005, 04:41 AM

Except that when you slip that little clutch under load you're going to heat check your flywheel, which is a whole lot more than a hundred bucks.

Posted by: BIGKAT_83 May 9 2005, 05:23 AM

The 8" clutch can be made to hold as much HP/TORQ as the 9". In fact Kennedys highest rating is for the double disk 8" packages.

The main trouble with the 8" is the pedal pressure with the high torque clutches. It takes more clamping pressure at the pressure plate and this makes for a very heavy clutch pedal.

I don't think I'd use the clutch to protect the transaxle. I suspect about 3 or 4 seconds of slipping at full load and you would be replacing the clutch,PP & flywheel at a little more than $100

Bob