BBK UDP kit questions
09-30-2011, 11:31 AM
#1
BBK UDP kit questions I came across this kit yesterday and I'm very tempted to buy it
http://www.byunspeed.com/product_inf...oducts_id=8426
What all does this kit include? I see the UDP, obviously, and that second pulley is a alt pulley im assuming? Underdrive or overdrive?
Then it says "ALL BBK performance under drive pulley kits use existing factory serpentine belts."
is this
?
and say if it is would I want a underdrive or a overdrive alt pulley to handle charging issues?
thx
and yes i did google and ls1tech search
http://www.byunspeed.com/product_inf...oducts_id=8426
What all does this kit include? I see the UDP, obviously, and that second pulley is a alt pulley im assuming? Underdrive or overdrive?
Then it says "ALL BBK performance under drive pulley kits use existing factory serpentine belts."
is this
? and say if it is
would I want a underdrive or a overdrive alt pulley to handle charging issues?thx
and yes i did google and ls1tech search
09-30-2011, 11:40 PM
#6
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It's a 10% underdrive for the crank and yes the small one is the alt pulley, I've had my set on my LS6 for almost a year with NO Issues. You want an UNder drive (smaller than stock) pulley for the crank and OVER drive pulleys (Larger than stock) for everything else. a good analogy is how it feels when you use the smallest crank sproket ant the largest wheel sproket on a bike you can climb steep but slow, on an engine you use less power to turn the driven accessories with an under drive crank pulley. But it can turn some things too slow like the alt, thats why BBK gives you a alt pulley to compensate for the under drive crank.
Last edited by Anthony Williams; 09-30-2011 at 11:50 PM.
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10-01-2011, 02:27 AM
#8
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It's a 10% underdrive for the crank and yes the small one is the alt pulley, I've had my set on my LS6 for almost a year with NO Issues. You want an UNder drive (smaller than stock) pulley for the crank and OVER drive pulleys (Larger than stock) for everything else. a good analogy is how it feels when you use the smallest crank sproket ant the largest wheel sproket on a bike you can climb steep but slow, on an engine you use less power to turn the driven accessories with an under drive crank pulley. But it can turn some things too slow like the alt, thats why BBK gives you a alt pulley to compensate for the under drive crank.
And, why would you slow it down at the crank and then speed it back up at the accs themselves? That just defeats the purpose of the UD to begin with. The only time you need an overdrive alt pulley is if you have a stock idle rpm and heavy acc use (such as lots of idling with the AC wide open, or big stereo). Once you cam or raise your idle, it offsets the idle speed of the accs with an underdrive pulley. An example would be autos idle at 550 in gear stock. My car currently idles at 850. My accs spin faster now with an underdrive pulley then they did when the car was stock because of the raised idle.
Last edited by 01ssreda4; 10-01-2011 at 02:36 AM.
10-03-2011, 03:34 PM
#10
yeah I would want something that diddn't interfere with the charging, I do want to run a 'system' eventually but im performance minded right now. I also like to have my a/c full blast sometimes, especially when the girl is in the car during the hot summer days in deep south texas.
I got to check my idle, I think it is at 850 after my tune.. its def above 500, so if my idle is set a lil higher then I wouldn't need a overdrive pulley for my alt, I think i got that right?
I got to check my idle, I think it is at 850 after my tune.. its def above 500, so if my idle is set a lil higher then I wouldn't need a overdrive pulley for my alt, I think i got that right?
