So, I'm making a lot of progress on the supercharger project. Currently working on the Honda radiator/intercooler/possible intake box frame, with molding/casting the blower intake and outlet manifolds as the last major fabrication step.

I plan on running the blower, sans plumbing, on the stock engine for a while, to "field test" the bracket and pulley arrangement I've fabricated, before proceeding with the final few odds and ends, and tuning. This brings me to my question: finding the appropriate belt length.

I know that an LL0 with no P/S or A/C uses a 55" belt. The intended setup is that, plus length for the blower and idlers, which comes out to a 71.5" belt, a 16.5" increase in length. Doss this increase scale up? To install the blower on the current engine requires a belt with P/S taken into account. An LL0 with P/S, but WITHOUT A/C, requires a 64.5" belt... So can I just buy an 81" belt (64.5 + 16.5)?

I'm just trying to get an idea of the proper size, without having to use the string method with the engine in situ, and without having to buy half a dozen belts trying to get it right.