Yup , underdrive pullies ASP pullies to be exact , experience ?? worth it ?? figure it mite work well with my E-fans on some power maybe a mpg.. lets hear your thoughts..

 

I have the March set.

"Gen" light comes on when e-fan kicks on.

Iguess it made a little power difference. MPG... not so much.

Wish I could say otherwise.

 

I heard mixed reviews. If you are going Pure Horsepower and dam everything else yes. If you are keeping your A/C, power steering, etc then no.

You lose power to your alt, A/C, Power steering & the rest. You will also put extra stress on those components. Underdrive will get you a few HP put may kill some other parts sooner.

Jeff

 

I didn't notice any difference in the A/C or Steering.

Gen light comes on but high power stereo still works fine.

***Gen light only comes on at idle***

I got mine for a deal on e-bay.

Oh.. one more thing... make sure you don't have a press on water pump pulley... ask how I know.

 

Pa,

I have ASP's also but installed them with my e-fans. Together there was a noticable difference in horsepower. I also have increased and maintained a 14 mpg in the city since the install. The only time you will notice a difference in your accessories (ac, alt) is at idle over a long long period of time without moving the truck. Your accessories will be at full operational capabilities at 1100 rpm instead of 900. The pullies are designed to take stress off the engine and to free up horsepower by slowing down the components. There is no stress put on components. In reality it helps them by running them slower when not really needed.

I do want to hear about the pressed on pulley mishap.

 

For some reason I was just not having luck the first time I tried to put the pulley's on. I was doing the plenum at the same time and things just were not going my way. Was taking too long to do easy tasks. Well after getting everything back together I went to install the water pump pulley and... no dice. I had replaced the water pump 2 or 3 years ago. It was aftermarket with a pressed on pulley. I had to take the other pulley's back off and wait til the water pump needed replacement to put the March partson.

Luckily the water pump bearing started making noise a few months ago. I found a new OEM pump off of a 1992 on e-bay (bolt on pulley) for $80 and threw that on. While at it Ireplaced thetiming gear/chainset and putthe March pulley's on.

Basically... if you have replaced your water pump with one that has a pressed on pulley you can't install the aftermarket water pump pulley. I don't know ifthat set you guys are using (ASP?) comes with one or not. The March set came with alt, crank and water pump.

 

oops...

 

so now that everyones off track on what this topic is about back to reg scheduled broadcast ....are they worth it and is there any hp gains or what are the pros and cons.......j

 

Underdrive does add a few HP.Call it a second stage upgrade. Not like a chip, Fastman, or done up exhaust. But the butt dyno will notice. Add electric fans to keep your engine cool. Otherwise your fan will be running slower


Like the guys noted your ALT, A/C & such run slower. I mentioned stress because your components were meant to run at a certain speed. At idle or low speeds they don't get the horses they need to run at their best. Your ALT will not handle the load at idle and you will be running down your Battery. That is why the guys get a GEN light.

Jeff

 

I suppose that you could buy a higher amperage alternator, but that makes this upgrade kind of expensive. Also it looks like the march set comes with a couple new pulleys probably to keep somethings turning at a certain speed. I would say if you idle around alot then, the underdrive may do more damage then good.