ACTman
Rock Sponsor (Level 1)
- First Name
- Dirk
- Joined
- Apr 23, 2019
- Threads
- 1
- Messages
- 102
- Reaction score
- 241
- Location
- Lancaster, CA
- Website
- www.advancedclutch.com
- Vehicle(s)
- 2015 Jeep JKUR, 2003 Jeep Wrangler
- Occupation
- President and head cheerleader at ACT
The stock flywheel weighs 29.5lbs and the whole stock clutch/flywheel assembly weighs 49.5lbs. For a comparison, the important number is the moment of inertia (MOI), not weight. I haven't tested the StreetMass behind the wheel, but the heavier ProMass feels really well matched to the vehicle in my opinion. We knew some people would be nervous about a big change in inertia so we opted to offer two weights. With our clutch kit and the StreetMass flywheel, it adds about 25% more inertia and the ProMass is about 50% if I recall.My experience is anecdotal, at best, but I really liked the 6puck ACT clutch in my 240sx. I beat on it mercilessly and it held up well. ~$1100 for the ACT plus flywheel isn't bad.
Dirk, for the layman and someone new to 4x4s, can you expound on the results behind the steering wheel between the street and promass flywheels and why the weight varies so much between stock and other manufacturers who have flywheels up to like 67lbs? IIRC the stock flywheel is something like 48lbs whereas the street and promass are 29 and 41lbs respectively according to the one-sheet.
With all that said, I forsee myself installing one of the ACTs, almost certainly laying on my back cradling my transmission on a floorjack.. wouldn't be the first time though.
It's hard to explain the behind the wheel experience. The drivability and rev-hang (stupid electronics) and stock weight seemed a bit weird which is why we opted to increase inertia even with our StreetMass. The best thing I can say about driving with the JP6-HDSS kit (includes the ProMass flywheel) is that you don't find yourself thinking about the clutch. In my opinion it just feels natural for the vehicle. With the added inertia, it will make it more enjoyable and forgiving off-road and/or especially towing.
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