What's an under drive pulley and what's it do?
02-17-2006, 01:41 AM
#2
Underdrive pulleys do just that, they underdrive engine driven accesories by changing the diameter of the pulleys. Smaller pulleys on the crank and/or larger pulleys on the accesories(power steering pump, alternator, etc). This makes the accesories spin slower, thus consuming less power. Beware however, underdriving your accessories too much can cause problems like not having enough power to keep your battery charged or run a large stereo system. If you drive relatively slow these are not for you. Only aggressive drivers should really consider these.
02-17-2006, 01:41 AM
#3
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Underdrive Pulleys are supposed to reduce parasitic drag placed on the crankshaft by underdriving the accesories such as the alternator, power steering and air conditioning. Underdriving slows down the accessories to use less energy from the crankshaft but not to the point the accessory operation becomes effected (in theory).
02-17-2006, 08:33 AM
#5
Safety Car
with all of the above...I have one on my 97 Auto and it did make the car seem a little more aggressive...besides the original one was coming apart
one thing I do know- when I sit at idle (in gear) the volts go down to 11ish...they come right back up when I start to move though...I don't notice any lights dimming or anything, and everything else works perfectly...I did this in concert with a few other mods - so I can't say exactly what it did as for HP increase...some claim 10HP...
02-17-2006, 01:38 PM
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I'm a new owner of a Powerbond 25% underdrive pulley, and so far I have noticed no difference in charging, steering or cooling performance from stock. Also, the C5 uses a separate belt to drive the A/C compressor. The aftermarket underdrive pulleys only change the diameter for the main serpentine belt and do not change the diameter of the A/C belt channel. Your A/C performance is not affected by the UD pulley.
02-17-2006, 01:39 PM
#7
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St. Jude Donor '06-'07-'08-'09-'10-'11-'12
Originally Posted by sweetvet
Underdrive Pulleys are supposed to reduce parasitic drag placed on the crankshaft by underdriving the accesories such as the alternator, power steering and air conditioning. Underdriving slows down the accessories to use less energy from the crankshaft but not to the point the accessory operation becomes effected (in theory).
02-17-2006, 02:46 PM
#8
Safety Car
Originally Posted by Jim Taylor
I'm a new owner of a Powerbond 25% underdrive pulley, and so far I have noticed no difference in charging, steering or cooling performance from stock. Also, the C5 uses a separate belt to drive the A/C compressor. The aftermarket underdrive pulleys only change the diameter for the main serpentine belt and do not change the diameter of the A/C belt channel. Your A/C performance is not affected by the UD pulley.
Not all....my ASP pulley is 25% on the main belt and 10% on the AC thus requiring two new shorter belts...
By the way, this does not effect the AC in my situation.
02-17-2006, 02:53 PM
#9
Race Director
Originally Posted by byte_me
Not all....my ASP pulley is 25% on the main belt and 10% on the AC thus requiring two new shorter belts...
By the way, this does not effect the AC in my situation.
By the way, this does not effect the AC in my situation.
no issues here but its npot worth doing it alone. do it when you upgrade your cam. too much work for just 5-7rwhps
02-17-2006, 03:10 PM
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Originally Posted by byte_me
Not all....my ASP pulley is 25% on the main belt and 10% on the AC thus requiring two new shorter belts...
02-18-2006, 08:04 AM
#11
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St. Jude Donor '12-'13-'14
I had one installed when I had the cam put in. To tell you the truth, im not sure for $300.00 dollars it does much. I surely noticed no differance on the electronics and power steering, so that was the good side. In theory, it should do something for the car, but im not sure it's noticable.
Its one of those parts that you do because it doesnt hurt so what the hay.
But if you go by the theory of every little bit helps, then :
port your throttle body $150.
change your MAF $300
do the by pass $10.00
get an X pipe $250
buy a high flow air bridge $150
change to ASP 25% $250
all the free mods
the list goes on, and you will pick up 15 RWHP
Did we all do these, Ummmm yes. Is it cost effective. doubt it. I should have just gone with a larger cam . lol
Its one of those parts that you do because it doesnt hurt so what the hay.
But if you go by the theory of every little bit helps, then :
port your throttle body $150.
change your MAF $300
do the by pass $10.00
get an X pipe $250
buy a high flow air bridge $150
change to ASP 25% $250
all the free mods
the list goes on, and you will pick up 15 RWHP
Did we all do these, Ummmm yes. Is it cost effective. doubt it. I should have just gone with a larger cam . lol
Last edited by phils C5 vette; 02-18-2006 at 08:26 AM.
