Stock Air Filter restriction

[Hoople]

Your information is Very good to know. Nice work.

Not that it would change matters much, it's more important to measure the pressure drop vs engine RPM than it is by the gear used. What you really want to know is what the pressure drop is at say idle, vs 2500 RPM vs say your max comfortable upper RPM limit. (whatever that may be)
It may be very small but you should see an increase in vacuum as the rpm is increaed.

 

[wilks3]

Hoople, No vacuum measured at idle all the way up to 60MPH shifting thur gears at approx 2200/2500 RPM. Even in 5th gear at 60MPH I didn't see vacuum until almost full throttle, and then it was 1" vacuum. Only when throttle was approx 70% to WOT did I read vacuum. This tells me the HD air filter is still pretty good after 4500 miles, and really not that restrictive either.
wilks3

 

[HDSickness]

Wow! gotta love American ingenuity.:newsmile108:

 

[Jack Klarich]

Vacuum decreases about 1 inch for every 1000 feet above sea level:s

 

[wilks3]

Smitty, All my little test showed to me was, 100% of the time, the way I ride, the stock air filter/air cleaner assembly has no restriction at all effecting performance on my FatBoy. If a guy rides hard with WOT, the stock AC/AF will be somewhat of a restriction. Would be more if pipes and a fuel control was added.
wilks3