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Old 12-26-2010, 06:55 PM   #1
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Default Current accepted drivetrane loss data

After quite a bit of reading here, m.net, and various other sites. My knowledge points me in the direction of (static loss + smaller non-linear friction dependence on power output.) So static loss + % total power loss. However, the % total power loss is small. The later is small enough that the larger the power output, the % total parasitic loss actually decreases.

Emelio suggested 35HP in a recent rotrex thread. He specified that this is widely accepted, but the criteria of its acceptance was not specified. i.e. 35 HP at stock, 211HP as tested, or up to 500HP.

My point is that on a 200 hp motor there would be a 17.5% drivetrain loss, and on a 350 HP motor it would be 10%.

Why is this important to me. When selecting a clutch for a dual duty car, there sometimes comes a point when you are approching the organic disk/ 6 puck threshold.

I am at this junction.
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Old 12-26-2010, 07:00 PM   #2
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I think the 35hp loss refers to stock or near stock cars. Not much more than 200hp or so.
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Old 12-26-2010, 07:20 PM   #3
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Just do the 6 puck unsprung hub clutch, i did it and loved it. You just need to rev it up higher then a normal clutch but other then that i don't think they are as bad as people say.
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Old 12-26-2010, 07:26 PM   #4
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"not as bad as people say" really doesn't sound encouraging to me, I dunno about you.
I have a sprung 6-puck and it sucks in traffic/city driving when it warms up.
Are you suggesting a non sprung would be MORE pleasant in said conditions?
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Old 12-26-2010, 07:57 PM   #5
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It depends on the flywheel and the pressure plate - I DDed a stock flywheel, 1.8 ACT HD, sprung 6-puck for ~30k in my black car and it wasn't all that bad. Everyone would stall it once but once you got the "blip-slip-go" routine down it was fine. Stop-go traffic sucked a little but just driving it around town wasn't hard at all. The only annoying part was that it would shudder in reverse if you didn't blip the throttle like a ricer.

The rental car's original clutch was a 10lb Fidanza, 1.8 ACT XT with a 6-puck (forget whether it was sprung/unsprung) and it was the worst clutch/fly I've ever driven - nearly undriveable on the street, way worse than my 949 cerametallic twindisc. I'm sure you could get used to it, but you wouldn't want to.
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Old 12-26-2010, 08:03 PM   #6
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I have the XT with a 6 puck. Stock FW.
Quote:
The only annoying part was that it would shudder in reverse if you didn't blip the throttle like a ricer
this is spot on.

Overall its not completely horrible, but definitely takes effort to live with.
When cold (or about 20 minutes or less driving) its fine. When it heats up it just gets more and more grabby.

I'd suggest either a combination of hd + extreme pressure plate or 6puck + ss pressure plate. Not both.
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