ive seen performance pulleys everywhere and every bragging about having them, i was just wondering if there is actually performance to be found or if its just a waste of 100 bucks? any help will be greatly appriciated im looking for everything i can to wring more horsepower from my car thanks

 

The ONLY one I would waste my money on... and I do mean waste.... is a smaller pulley for the water pump. By doing that you will increase the flow rate. side note: Another trick is to take the water pump off and attach a plate on the impeller on the side closest to the block (use rivets). That will give the water pump a more direct shot.

Of course enlarging the size of the crankshaft pulley will have the same effect, but will also speed up the RPMs on all other accessories. But that has the same effect as switching to 10th gear on your 10 spd. bike. It allows the smaller gear (rear gear on your bike) to turn more RPMs from less RPMs on the crank gear, but remember how that KILLS your legs after a while? That's because it takes more power from your legs to turn the crank.

They way they set it up is to decrease efficiency (# of RPMs) on the power steering pump and the water pump, and increase the efficiency of the crank (needs less power to turn the accessories). Some kits use a smaller pulley to increase the RPMs of the altenator to increase it's output at idle. But I don't know how much. They never give specs on that. I wonder why? Maybe because it's not worth printing?

I guess they have there perks, but will you see a 20HP gain from changing them? No. Not unless it's a 500HP motor.

AJ

 

A smaller pulley on the alt is very beneficial. By overdriving the alt, you get a bit more juice at idle. I read the overdriving is in the 20% range. But because the surface area of the pulley is smaller do to the decrease diameter of the overdrive pulley, cheapo belts tend to squeal. I use a Gates belt with my overdrive pulley and there is definitely a difference at idle when there is a high load placed on the alt.

 

I had a three peice pulley set on my 87 Mustang and the was quite a bit of difference in the speed that the rpms increased . I have an undersize Crank pulley on my car now(Vbelt) and have had it for 4 years from the pulley alone I gained 2 mph when my car had a 305 , When I broke the belt and had the stock pulley on for a month I lost just under 2 mph at LACR , and again there is a difference.

 

in '95 when i had my '95 3.4 v6 i gained 10.5 peak hp. had the car dyno'ed before and after. lost some low end hp before 2500 rpm. but gained it above that. it was a 2 piece set. crank and alternator.