Trmachuno

Is it OK to run Underdrive Pulley's and the Shaker 500 if so or not what would my rwhp gains be?

94Blk5.0

I have UDP's with a Mach 460 stereo, and the amp needle will go down at idle, regardless of the radio on or off. The lights will dim at stop lights ideling but that about it. Expect 5-10RWHP. once you get the rpm's over idel the amp guage remains as it would normally, and it also depends on how much the altenator is under driven as well.

Trmachuno

So do u think the UDP were worth the price? Have u ever stalled out? U say after u get the RPM's above idle it returns to normal, is this only before the car warms up? What % Underdrive Pulley u running?

Thanx

Trmachuno

PS: What if I just run an underdriven crank pulley u think that will mess with my alternator and what gains should I see from that?

Thanx

NickSezz

The only ones I know of for the 4.0 is the crank pully, which effects all accessories on the engine (ex, a/c alt.) and the alternator pully alone.

If I remember correctly someone tested these out alone and then together. The result of the less expensive alternator pully was 5-7 hp I THINK...or was it 3-5? lol. The crank pully yielded a similar gain but is said to not be worth the money. Together the two yielded no gain...so one has to pick between the two.

As for running them with a system, you will lose some amp power no matter what one you choose. But I dont think you have to worry...

Trmachuno

Thanx how much is the each pulley?, where can I order them?, when u said 5-7hp u meant rw right?,and do I need a new belt if I got either one of them?

Thanx for the info, helps a lot!

NickSezz

You can find the crank pully here http://www.v6mustangstuff.com/05Engine.htm

The other atl pully can be ordered from here...have too call them I guess. http://www.paulshp.com/

The hp is to the wheels but im not sure on the numbers. But the alternator says 3-5...

94Blk5.0

The alt. output might decrease at idel speed with the new pulley, but once you step on the gas the rpms increase, therefore the alt. is spinning faster resturning the output to a normal state while driving down the road. As far a percent of underdrive, I dont know, I bought the car with them on it.

ezell504

Could all of this be solved by simply using a compacitator? They are used to balance out power from the battery to the speakers. Just a thought because i was thinking anout gettint the UDP's. And without a system, do they affect the car in any way?

musicheadt

I think you meant a Capacitor?.....an electronic component that stores voltage while running at normal RPM........and discharges needed voltage at idle? ***As an electronics technician...I would NOT recommend this***...you would have to have a very balanced Capacitor system to make this work well...Capacitors don't partially discharge......the drop voltage into circuits all at once. A cap system can cause major electrical problems. You have me wanting to experiment with it though......if/when I put underdrive pulleys on.....I might play around and see if a capacitor might help the voltage lag at idle.
Have you seen any posts about people using Capacitors to compensate for idle voltages with underdrive pulleys?