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Old 01-01-2011, 04:52 PM   #1
lionsault
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Default Lightwieght crank pulley. Good or bad idea.

2010 n/a hatch.
I wanted one for a while and I heard people say it's a good idea and some people say it will kill my car. I read a bit on here when i can find something. People are still split about it. So I just wanted to know more about the good and bad or getting one. Thanks peeps.
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Old 01-01-2011, 04:58 PM   #2
Seventh
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I ran an unorthodox lightened under drive crank pulley for over 100k miles on my GC, only problem was momentary belt squeal on cold start up in sub-freezing conditions. Awesome when coupled with light flywheel. I'd do it again.
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Old 01-01-2011, 05:14 PM   #3
lionsault
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Sweet. I like the idea of it. I read that it frees up the rps especially the low end. But a little squeal is worth it.
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Old 01-01-2011, 06:42 PM   #4
gurana
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Like many mods, there's some disagreement as to it's merits. Personally, it seems like an easy, not too expensive mod most could do themselves and probably see some tangible result... unless you pair it with a tune. This would obviously increase the cost. My understanding is that it's not explicitly necessary, but will get the most out of the mod.
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Old 01-01-2011, 08:49 PM   #5
Back Road Runner
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The pulley offers very little change in energy consumption. It equates to about 1% change which is pretty much just enough...to not feel it. If you work through the math, the difference in energy between stock and a very light pulley is just quite small.

Every little bit does count though, so pulleys are an eventual upgrade at some point. It's just that other things offer better gains, like the flywheel. Even things like engine internals like lightweight pistons, rods, and flywheel, low friction coatings, low friction rings, and such are also aspects one would be looking at for reduction in energy consumption during engine operation. Due to the high rotational speeds and high part speeds, these can be quite a significant amount energy invested to rev up the engine and energy lost every time you slow down.
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Old 01-02-2011, 03:31 PM   #6
lionsault
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Wow. That's deep. I guess I made up my mind. Thanks for the info.
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Old 01-03-2011, 02:04 AM   #7
Suby<3777
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I would stay away from under driven pulleys for they steel power from your accessories. It's not exactly a good thing to take away power from your water/power steering pump that pump important fluids through your steering rack and engine, or steeling power from your alternator aspecially if you have a sound system. Also under driven pulleys have been known to through CEL's in some small cases. I also had the problem with a belt squeal using an under driven pulley before. I would go with Kartboy's light weight crank pulley(not under driven). It's not light enough to through a check engine light but plenty light enough to make a small difference, and still a ton lighter than the stock crank pulley. There are also some company's that make light weight pulleys for your alternator and power steering pulley's which would free a little more weight off the crank. Good luck to ya

Last edited by Suby<3777; 01-03-2011 at 02:10 AM.
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Old 01-03-2011, 08:25 AM   #8
treksofar
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I'm running a perrin lightened pully and a 13lb flyweel...love it! no CEL issues, revs faster, throttle response is snappier, and pulls a tad harder. however, when i had the lighened pully by itself, i really didnt notice much of a difference...but like it was mentioned above, every little bit counts.
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