Any Gains with an underdrive pulley setup?
Any Gains with an underdrive pulley setup? Ive had a couple of these sitting around that came on previous cars Ive purchased, are these even worth putting on or are they a waste of time?
What type of gains is there 5-6HP?
What type of gains is there 5-6HP?
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Joined: Jan 2010
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From: New Orleans, LA
My car revs quicker, thats about the only thing Ive noticed. I bought the bbk pullies, the alternator pully didnt fit my alternator shaft (replacement alt) so Im only using the crank pully for now.
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From: LT1 land...the "409" of the 90s!
No HP gains will show but performance will pick up. It is like putting lower rear end gears on you engine. It will rev quicker 
Back in 92 I put a set of march under drive pullies on my 74 Z28 and picked up a consistant .20 in the quarter on a 12 second car
Back in 92 I put a set of march under drive pullies on my 74 Z28 and picked up a consistant .20 in the quarter on a 12 second car
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From: LT1 land...the "409" of the 90s!
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From: centerville, ohio
We have a 4 hp gain on the dyno, apparently from a set. Not the 1 hp gain from a single crank pulley from the WS6 site that everyone takes as the gospel. There are gains to be had.
My old Formula runs the ASP 23% underdriven pulley/balancer combo with the matching alternator pulley...been on since 1996 and picked up 3-5 rwhp across the entire rpm range on Lingenfelter's dyno back in 1996. Imho every little bit helps...Is it worth the money/hp? Thats goona be your call..
--Alan
--Alan
My old Formula runs the ASP 23% underdriven pulley/balancer combo with the matching alternator pulley...been on since 1996 and picked up 3-5 rwhp across the entire rpm range on Lingenfelter's dyno back in 1996. Imho every little bit helps...Is it worth the money/hp? Thats goona be your call..
--Alan
--Alan
Ill stick them on, Couldnt hurt anything. Im hoping an electric water pump, drag radials instead of bias ply and the underdrive pulleys will help make up for the added weight of a rollbar.
Thanks for the responses guys
Austin
Only difference I really noticed was my A/C now feels like theres a little person behind my dash blowing air on me instead of a nice cooling breeze...but the steering feels a little less dead. Nothing felt in the seat of the pants-o-meter though
I have the ASP kit, didn't really notice much. If you get one make sure if you get a kit to get the alternator pulley as well so you do not have charging issues. I ran it without the alternator pulley and voltage would drop at idle with the lights on, not safe in stop in go night traffic. I wouldn't say its a bad mod for the price, the torque gains are proven. Just posting my experiences.
Last edited by 96blackz28; Mar 21, 2011 at 10:55 AM.
The underdrive set (not the piggyback) work great on H/C cars that already have a higher idle.
Cars with a stock idle often report charging issues.
I was very pleased with the way the H/C 350 felt with the 23% ASP kit.
I did not have charging issues or a/c problems. My idle was around 825.
I ran a similar set on my H/C 3.4 back in 1999, I didn't notice much (if anything)
I run a 10% underdriven balancer on my 383 with the stock alt pulley and have no issues, but I idle closer to 1050.
I don't have a/c anymore (compressor died and I don't drive it enough to care).
So, as mentioned above; minor gains but nothing spectacular.
Cars with a stock idle often report charging issues.
I was very pleased with the way the H/C 350 felt with the 23% ASP kit.
I did not have charging issues or a/c problems. My idle was around 825.
I ran a similar set on my H/C 3.4 back in 1999, I didn't notice much (if anything)
I run a 10% underdriven balancer on my 383 with the stock alt pulley and have no issues, but I idle closer to 1050.
I don't have a/c anymore (compressor died and I don't drive it enough to care).
So, as mentioned above; minor gains but nothing spectacular.
