Under drive pullies

[jjhirsch]

When people install them what is the point of even installing the water pump pully? Why not keep the stock one installed?

[FortiethStang]

Under drive pulleys are a waste of money altogether.

[mnstang]

What do you mean what is the point? Is this a trick question?

The point is to spin the water pump slower. Reducing drag. Freeing hp. Same point as the alternator pulley, and crank pulley.

[TRDon]

Don't buy the junk aluminum ones and you won't have the issues with the water pump pulleys you have had in the past. Problem solved

[iamtheshaner]

Waste of time. Why anyone would reduce cooling ability I don't know. Spin alt slower = stronger fielding = requires more torque to spin. They are for super duper racercar racers who need to eek out every last pony

[jjhirsch]

Well I have just a underdrive crank pully as of now and was thinking of just putting it on with the stock pump pully. I didn't relies that the bigger water pump pully was part of the small hp gain. I thought it was to make up the slack for the belt to fit because of the smaller crank pully.

So would it be worth any to change my crank pully or just buy a new set?

[TRDon]

Different crank will help but not get you the full gain. Obviously you will need a new $40 belt for it. Or for $100 just get a new pulley set. guys in this thread are on crack, my pulleys made a massive difference on my car. went from not spinning the tires to spinning tires with just pulleys. i even switched back just to see if that was the cause and it was. $100 well spent. for you, it depends on if you want to spend the money.

[mnstang]

Waste of time. Why anyone would reduce cooling ability I don't know. Spin alt slower = stronger fielding = requires more torque to spin. They are for super duper racercar racers who need to eek out every last pony

i don't think a cars cooling ability is hinged on waterpump output. i've had underdrive pulleys on my mustang for over 10 years and the only time i've had a hard time cooling is when i built my 331 and was still using an old stock radiator. with 5.0 fords you are not compromising the cooling performance at all with an underdriven waterpump. also have them on my 5.8 f150 with zero cooling issues, maybe i'm just doing it wrong.

yes, they are for racecars only. because 5hp for $100 is totally not worth it. i've done alot more for alot less gain before. i'm guessing your car is an under achiever with your mentality.

[octanehuffer]

I went from a 16.9 to a 13.2 with under drive pullies. Then I tried race gas and went too fast without a 7.50 certified cage. Got me kicked out of the strip for the day.

[jjhirsch]

I was thinking of putting the under-drive crank pully on just because i have one and leaving the stock water pump pully so i dont have to spend $100 just for that pully. Then getting a belt that would be smaller to bypass my AC and Smog pump while i am at it.