I am looking for an underdrive pully for my car and was wondering if asp and slp pullys will provide the same % underdrive and which will add more power?

 

If you get the 25% underdrive, they will give you the same gains. Personally I like the SLP/powerbond pulley the best, but do a search and see which one is the most reliable and get that one. Don't decide based on power because they will both show equal gains.

 

I'll be getting the 25% underdriven Powerbond from TSP in about a month. Comes with belts and crank bolt.

 

what kind of gains to the under drive pulleys give? I have a complete bolt on car w/a G5X3 cam in it and im wondering if its worth it to get the ud pulley (its the only bolt on i dont have besides heads) so do you guys think its worth it?

 

Yes, they should show the same gains. A pulley is typicall worth 0.1 and 1 mph in the 1/4. The ~10rwhp may or may not show up on the dyno...but the gains are there.

It is definately a worthwhile mod.

 

^ What he said.

 

and "SEARCH button...it's your friend" ..........

now that we have that out of the way..........


1) ~10 HP......it is enough that on a stock/mild bolt on car you can feel it.......
2) the engine will run cooler as there is less load (P/S pump, alt, AC, water pump) so you don't generate as much heat......even though you slow the water pump down (would rather it stay "faster") the drop in load > the drop in water flow....
3) the P/S will run cooler
4) depending on electrical load, auto cars CAN see problems at idle because
a) they already idle at a lower RPM
b) the alt is now turning even SLOWER
4.1) I personally say put the overdrive alt pulley on ANY car that has an under drive pulley (auto or manual) because the alt HP drain is VERY small.....
5) undrive pulleys are 5000000000000 times easier to get on and off the crank than the stocker is.......I personally WILL NOT help with a cam swap if the stock pulley is being used........


under drive pully = good mod

 

Are you sure the engine will run cooler? I think it would run hotter since you are slowing down the water pump......

 

I have a digital water AND oil temp gauge........back to back test showed lower temps.........


again.....the drop in load > the drop in water flow = cooler temps.......

 

I think he is trying to say that although your water pump is running slower (which would make it run warmer), you are also turning things slower that add heat (like the PS pump, etc). So the net cooling you get is > than the decrease in water flow.

I'm not sure if I agree, but then again, I haven't logged any data since my UD pulley install. Might have to check this one out.

 

Yeah, I see what he is saying, just doesn't sound quite right to me. When I got my car out for the first time with the pulley it DEFINATELY ran a lot hotter than before, BUT the outside temps were higher than they had been for over a year so who knows how much of it was the higher stall converter and dumping more heat from the tranny into the radiator combined with the temps and CAI.....we've had 20 days of 90*+ now with basically all the rest up in the 80's, with PLENTY of humidity whereas last year the single hottest day was 87*. Makes it hard for me to draw any real conclusions.

 

Yes, it is. www.texas-speed.com

 

This a really dumb question but is the TSP everyone talks about Texas Speed & Performance.

 

Wow. Do you guys see that? I answered his question and it put it ABOVE him.

WTF?!

Edit: For future reference:

https://ls1tech.com/acronyms.html

I guess I'm just that damn good.

 

 

If you have a M6 don't waste your money on an overdrive alternator pulley. I didn't notice any negative effects with a 25% crank pulley. The money you waste will just - hp.

 

Same here with my M6...no difference at all in charging.

 

Anyone running the March pulley?? Like it? Not like it?

 

I am running the new SLP Pulley and I like it. I think I run a little hotter than before but that could be something else. The SLP looks good also.

Bill

 

I think I might run just a hair hotter also, but I didn't do just the pulley by it'self.