Help choosing underdrive pulley
However it's not needed unless you're running something inside the car that requires a larger amount (than stock) of voltage. A large stereo, double din TV's, etc.
That being said, I ran an ASP pulley in my 98 for 7 years with an Eclipse 10" sub and Alpine 300x1(rms) amp with no problems on the stock alt pulley. I saw a tiny voltage drop during certain songs, but nothing to write home about.
Anything larger than a 300w amp might require the ALT pulley, or just run a 1/2 farad power cap.
As I stated earlier I was leaning towards a fluid type from Speed Inc has anybody used this pulley? I just talked to Speed Inc & they said there's ways 13lbs
Last edited by dphc18; Jun 20, 2011 at 02:00 PM. Reason: change in info
I've been looking at these as well... Seems to me the asp is the favorite but with plenty of horror stories, and the slp/powerbond is good but heavier than stock... So without going heavier than stock is there a fluid option?
Do we know the exact weight of the ASP pulley? And why is the majority not interested in the fluid type is it not supposed to be better for engine life and knock sensor issues?
The new ASP pulley's are SFI approved, and do not come apart.
You can lead a horse to water..............................
Sorry, that made me laugh out loud at work. I rarely hear any belt throwing stories anymore, but for the added security I'm gonna get the SLP/Power Bond for the higher side walls. Wish we could have the best of both worlds and have the ASP with higher side walls.
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Verdad Gallardo My bad on the spelling error, anyways I talked to a bunch of manufacturers today and this is what I got,
Stock- 10.5lbs
ASP- 7lbs, has same height belt retention walls as stock 25%
SLP- 10.5lbs 25%
Fluid Dampner- 7.3lbs 10%
PRW- (also Fluid) 12.5lbs 25%
So I am now looking for an answer to the question, does the lighter weight make more power or not?
Manufacturers say weight makes a diff for road racing or circle track not Street/strip.
Stock- 10.5lbs
ASP- 7lbs, has same height belt retention walls as stock 25%
SLP- 10.5lbs 25%
Fluid Dampner- 7.3lbs 10%
PRW- (also Fluid) 12.5lbs 25%
So I am now looking for an answer to the question, does the lighter weight make more power or not?
Manufacturers say weight makes a diff for road racing or circle track not Street/strip.
I spoke with ati today about one for my car and they were very helpful and seems to be as good as it gets... Plus you can rebuild and change pulleys without buying a whole new setup. That's what im goof with
I got ya Josh, but lets look at things realistically. What you are arguing is spinning drag. So lets talk about that. All 3 that we are discussing that I know of are 2 piece designs. Meaning: 1 piece hub (what goes on the crank), 1 outer piece (where the belt rides) and the 2 pieces are connected by a ring of bonded elastomer (rubber basically). The problem at least originally with the ASP units was that (for weight reduction reasons) the inner hub piece was aluminum. This apparently caused some separation issues as the units aged. The stock unit is some kind of cast iron or steel and the powerbond unit is all steel. The Powerbond unit has raised steel beveled edges to help keep the belt from throwing. I think possibly the stocker is around 12-14 pounds, Powerbond is near the same, and ASP is about 10 pounds or so (all estimates). So, ASP managed to eliminate weight in the most unfavorable place, the closest spinning area to the crank snout. This would not be as beneficial as making the outer ring in aluminum. But, there has to be a reason why they didn't make the entire unit in aluminum...not stable enough, not strong enough, manufacturing costs etc. As an example of the spinning weight savings of a hub made of aluminum try swinging a 5 pound weight on a 3 foot string, then try it on a 1 foot string. On the shorter string you are actually moving the weight less distance therefor requiring less energy. The actual point of an underdrive pulley is to spin the accs slower and thats where the power/throttle response is gained. Adding 2 spinning pounds 1 inch from the cranks centerline is irrelevant in this case 
