Yes. I went about it differently though.

I multiplied the blower overdrive % by the HP level (350 or 400) and by a unit-less empirical factor that I derived to calculate the HP gained (boost) column. I similarly multiplied the accessory overdrive % by another factor I derived to calculate the HP lost (accessory overdrive) column. I subtracted the losses from the gains for the total HP gained.

Deriving the empirical factors is where the wild approximations come in.
I took the HP gains Eurocharged has published for their pulleys (which seem to be generally accepted as accurate) and adjusted the factors until the results generated matched up close to what Eurocharged has published. Initially I focused on the 65mm pulley and found the HP gained factor because there was only one to adjust since the 65mm has no losses from overdriven accessories. I then found the factor for the accessory losses that lined the 181 and 185 pulley results up with what Eurocharged has posted. I checked the numbers for reasonableness, and then played with graphs.

We know that above around 20% overdrive the supercharger efficiency starts increasingly limiting the HP gained. I made no attempt to factor for that reduced efficiency.


I ordered a 62mm pulley, so I am hoping your estimate is right and not mine!