Boost and pulley size of HD F150

[Orange Poison]

Got a buddy with a 2003 H-D F150....real nice truck.

Anyways, I'm talking him into getting a smaller pulley and tune.

So far he's gotten a drop in K&N filter....

But how about pulley size? I take it that the stock HD pulley is larger than the Lightning Pulley? If so, how much boost will he be pushing with the 2.93 pulley swap? Would it be better to go down to a 2.80 pulley?

Thanks for your help

 

[03DOHC]

I think they have a 3.1" upper. Lightning guys change the lower pulley more often than the upper.

 

[airtroop01]

Yup, the harley blower has a larger pulley, hence roughly about 2lbs less boost than a lightning. If he stays with the stock tune (meaning no chip), then I wouldn't recommend anything larger than a 2-4lb lower pulley (JLP, LFP, etc would all do). Swapping out the upper pulley isn't worth the work, when you can pulley the lower with more than enough boost to keep you satisfied. Plus, you get the advantage of less belt slip due to the larger surface area around the blower pulley.

 

[Rainman15]

I ran a 8lb lower lightning pulley on my 02 Black HD Screw, which due to the difference in upper pulley diameter netted a 6lb increase over stock. (12psi total) I did have a chip burned for it though. With a CAI, the chip and pulley I was easily laying 20' marks with 20" tires. It was really weird to feel something so big as that truck pull so hard, but it was nothing compared to when I added those same mods to my 03 Lightning. Traction is non-exhistant.