Calculating serpentine belt loading

[011554m37]

I have a 1954 Dodge truck I have retrofitted a 400 big block V8 Chrysler into it. I'm planning on twin turbo, and twincharging it. I have two Holset HX35's on it, and plan on fitting EFI. I plan on running compound boost using two Eaton M90's, similar to the WWII bomber aircraft engines. The two holsets will feed into the M90s. The question i have is on belt loading. Ideally, Id like to run a single 8 rib belt of the crank up to a jackshaft, then, drive the first blower off that jackshaft, and the second blower off the first by putting a double pulley on the snout of the first blower. Question I have is this:

Does anyone have any equations to calculate the power transfer ability of serpentine belts?

Each blower will consume about 35HP at full load, so I don't anticipate a single belt will be able to drive both from the crankshaft, but, I want to run the equations to be sure.

 

[patprimmer]

I would call Gates and ask for their technical support.

You need a considerable safety margin to cover load from pumping against boost, variations in friction due to rotor clearance changes from temperature changes. You also need to survive a backfire.

Blower belts tension also varies considerably due to engine expansion from heat.

Regards
Pat
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[BrianGar]

I have no Idea of that engine layout as Im from Europe but Weather should not be forgotten too, mist used to play holy hell with belt slip on a few VW G60s I had, even when I fabbed up different tensioners etc I would still get belt slip at times. Ok, road water can be shielded away from the engine, but mist/fog gets everywhere.
Its also depends of course on the type weather you get but here, lets say, it varies!

Brian.

 

[011554m37]

ok, so, I had a momentary loss of sanity...

I made the mistake of not cutting my displacement in half to acocult for the 4 stroke engine design. As such,I dont need to run the blowers as fast, only at a 1.5:1 ratio. At a 1.5:1 ratio, they only consume 9-10 hp a piece, for a grand total of 18-20ish, which is much less than a single blower running at a 2.5:1 ratio like I originally had factored. As such, I *Think* I could actually get away with a single belt, so long as I get good wrap of the pulleys.