why shouldn't you use UD pullies with a charger?

[yellowstang1994]

My friend has a powerdyne with 11lb pulley on his GT and is also using underdrive pulleys with it. I heard somewhere that by doing this it might cut down significantally on how much boost he is pushing. I told him what I had heard and he said he doesn't know why it would effect anything. Does anyone know the deal and why? Thanks

 

[Venom351R]

W/ UD pully's everything spins slower, the ALT pully, the Crank Pully and the water pump pully. If you have a super charger that runs off the crank pully and its being underdriven by a UD pully then it will not spin as fast and not make as much boost.

 

[davins130]

you could still keep your alt. and waterpump u/d pullies and just put the stock crank pully back on couldnt you?

 

[SN95StangMan]

I dont think a larger water pump pulley(underdrive) would fit with the stock crank pulley.

 

[95snoozer]

you could still keep your alt. and waterpump u/d pullies and just put the stock crank pully back on couldnt you?

alternator

but for cooling purposes...why? you have a blower...

 

[94Blue302GT]

yeah, just use the other UD pullies and put the stock crank pulley on. Sell the UD crank pulley on ebay.

 

[94Blue302GT]

oh, and if it says that you have a 20% underdrive, then you prolly have 20% less boost, makeing that 11psi more like 8 or 9.

 

[pwcracer]

That will not work.. I just found this out the hard way last night! I have U/D pulleys on my 94, I am installing a KB supercharger so I tracked down a stock crank pulley (Not the easiest thing to do) I went to put it on last night, and the stupid thing hits the U/D water pump pulley and won't go on. I called Ford to order a stock h20 pulley and found out that they have been discontinued since 2003!
Try and find stock pulleys for 94-95, not easy

 

[revhead347]

The rule really doesn't apply to our cars. On 94-95s, most blower kits use a seperate belt and a seperate pulley all together, so it doesn't really matter. 4.6s run the blower on the main serpentine belt, so you will underdrive the blower with underdrive pullies.

Kurt

 

[pwcracer]

It has to be getting the power somewhere, and if the crank pulley is running slower, wouldn't that inturn run the blower slower, and provide less boost? Thats why I am replacing my UD's with stock..

 

[yellowstang1994]

My friend's powerdyne does have the seperate pulley on the crank for the charger. So I can see why now that it wouldn't matter about the underdrive pulleys or not. But while I am here let me ask. Sorry if this sounds stupid but... On U/D pulleys they are basically underdriving (bigger pulley) the alternator and water pump to overdrive the crank (smaller pulley)? Is that correct or am I messed up?

 

[MysteryMachine]

That will not work.. I just found this out the hard way last night! I have U/D pulleys on my 94, I am installing a KB supercharger so I tracked down a stock crank pulley (Not the easiest thing to do) I went to put it on last night, and the stupid thing hits the U/D water pump pulley and won't go on. I called Ford to order a stock h20 pulley and found out that they have been discontinued since 2003!
Try and find stock pulleys for 94-95, not easy

I have all my stock pulleys if ya need them make me a deal

 

[cavscout371]

That will not work.. I just found this out the hard way last night! I have U/D pulleys on my 94, I am installing a KB supercharger so I tracked down a stock crank pulley (Not the easiest thing to do) I went to put it on last night, and the stupid thing hits the U/D water pump pulley and won't go on. I called Ford to order a stock h20 pulley and found out that they have been discontinued since 2003!
Try and find stock pulleys for 94-95, not easy

thats good to know I'll have to save mine when I do the pullies

 

[SN95StangMan]

My friend's powerdyne does have the seperate pulley on the crank for the charger. So I can see why now that it wouldn't matter about the underdrive pulleys or not. But while I am here let me ask. Sorry if this sounds stupid but... On U/D pulleys they are basically underdriving (bigger pulley) the alternator and water pump to overdrive the crank (smaller pulley)? Is that correct or am I messed up?

That's right. smaller crank pulley. larger accessory pullies.