there may not a whole lot of belt slipage but as you go to a smaller pulley to overspeed the blower and make more power you have less surface area of belt contact to drive the blower. and as you compress more air at higher pressures you run into the fact that the loads on the pulley/belt increase by several orders of magnitude (they estimate that the blower on a top fuel engine takes almost 700Hp to drive it at max power-remember they are making more than 6000 Hp-and have you ever seen how wide the belt is? it'* a gilmer belt to keep it from slipping and to prevent belt tensionloads that would kill the blower shaft bearings)
as you drive the blower to make twice as much power it take 4 times the energy to drive the blower the belt will slip-unless you increase the width of the belt, or the surface area (remember you lost allot of the surface area going to the smaller pulley) the other way would be to increase the pressure the belt places on the pulley (higher tension) but this would have the consequence of much higer loads on the crank/SC'* pulleys/bearings reducing the service life of them.
the best way around this is to gear up the supercharger to spin faster with a larger pulley, and since a custom machined (billet $$$) eaton snout with a planetary/spurgear inside the snout to drive the SC faster than the pulley is spinning (it would be at 4 inches etc for better belt grip) would cost allot to develop as well as manufacture (though you could make it with a 2 spd shiftable planetary-and change overdrives at the flick of a lever!).
I figured that this would be a practical alternative (as well as being able to package it at the tip of the snout-and not take up too much space) to reduce belt slippage which loses power (as well as it probably means better consistency in ET'*)
The other way would be to use a gilmer style belt to prevent the slippage but that would also necesitate custom pulleys etc
or you could drive a larger blower displacement at the same speed and make more boost but this would also require custom work as well as being a more expensive method (though much more efficient at compressing the air with less heat at the same SC shaft speed.
It was an idea i floated and wondered if anyone at Intense etc had thought of.
with this method you would have to do some work to a tranny planetary set and the only major mod i can see needing to be done is a bracket to hold the ring gear still, that bolts to the SC either to the bolts that hold the gearbox/snout on, or a simpler way would be an aluminum plate TIG welded to the snout in the right position that the ring gear would bolt to, and the sun gear would just have to be machined to press fit onto the SC shaft.
As soon as i find my autoCAD 3D cdrom (cant find it-found the books but no disc
) I will be working on packaging a design that would work, i can picture the design in my head (like the two small needle bearings to prevent runnout) but an actual diagram would be more explanatory and show how simple a design it is (besides you could drive the blower at a higher speed, like a 1 inch pulley LOL) and easy to implement-plus easy to change the drive ratio (just change the planet/sun gear sizes) without having to carry different belts.
its just an idea to fix a problem in an efficient way.
and still wondering if anyone at Intense has thought about something similar.