Morning Repost: Lightweight Underdrive Pully Set on a 2.7t
12-13-2002, 06:34 AM
#11
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I would never put any light weith pulley system on any car after my personal experiences...
My 98 M3, 002 Under Drive pulley, it ended up blowing out my crank oil seal (dealer took 3 months to find it too). My old room mates WRX read misfire codes due to his, this threw codes and pulled timing.
Light weight pulleys are mods that will yield you a few extra hp (no more than 5 real world hp) and possibly cause you a world of headaches. Not worth it, stay away people, just stay away. German cars, Japanesse cars, etc, they come with heavier pulleys for a reason.
Oh, and my fan cerpentine (sp?) belt would throw itself when revved to high rpms, mine was never exact factory thickness, even with the "spacers" installed. And a broken radiator fan is not a cheap fix. Only takes one time..
Phewwww, that's my $.02.
Light weight pulleys are mods that will yield you a few extra hp (no more than 5 real world hp) and possibly cause you a world of headaches. Not worth it, stay away people, just stay away. German cars, Japanesse cars, etc, they come with heavier pulleys for a reason.
Oh, and my fan cerpentine (sp?) belt would throw itself when revved to high rpms, mine was never exact factory thickness, even with the "spacers" installed. And a broken radiator fan is not a cheap fix. Only takes one time..
Phewwww, that's my $.02.
12-13-2002, 08:02 AM
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If you look at the reflected inertia the car represents to the engine...
... even reduced through the final and intermediate gears, I think you'll find the percentage benefit of a less-inertive pulley so small that you'll put your wrenches away...
If you look at just the engine's rotational inertia itself (as is relevant when declutched), even here the pulley component is very small and I wonder if you'd feel a difference in throttle response.
The underdrive issue is quite different; if you go to a smaller diameter you can see more substantive net power gains but is it worth it? On my Mustangs I could always, no matter what the weather or track condition, pick up a full mile per hour bypassing the p/s pump. But shutting it down completely is a far cry from just underdriving it, the water pump, and the alternator... Best I suspect just to minimize your electrical load when you're on it, unless our ECU does that itself...
If you look at just the engine's rotational inertia itself (as is relevant when declutched), even here the pulley component is very small and I wonder if you'd feel a difference in throttle response.
The underdrive issue is quite different; if you go to a smaller diameter you can see more substantive net power gains but is it worth it? On my Mustangs I could always, no matter what the weather or track condition, pick up a full mile per hour bypassing the p/s pump. But shutting it down completely is a far cry from just underdriving it, the water pump, and the alternator... Best I suspect just to minimize your electrical load when you're on it, unless our ECU does that itself...
12-13-2002, 08:56 AM
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I was hoping to get some more opinions and information.
I felt deleting last night's post would be better, that way people wouldn't automatically assume all questions were a dead issue.
I really appreciate the information you posted last night though. It was incredibly helpful.
I really appreciate the information you posted last night though. It was incredibly helpful.
12-13-2002, 09:15 AM
#20
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heres an awesome read on the subject- Subject car is a Stealth TT twin turbo V6!
Just know since this modification is unchartered territory you may or may nt experience problems, is the potential gains worth the possible risk? FYI the stock pulley IS a harmonic balancer!<ul><li><a href="http://www.pacarsearch.com/stealth/udp.htm">http://www.pacarsearch.com/stealth/udp.htm</a</li></ul>
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