131 is a diversed product that can be used in vertually everything from gas,L.P.G. and diesel fuels, crankcase oil, ps trans, rear end gear oils, and hydraulic systems. Also offers faster water separation from fuel,used as a fuel stabalizer for storage by inhibiting the oxidation of the fuel,lowers the waters freeze point, and is a lead replacement for reduced exhaust valve seat wear (recession) for both non-hardened and hardened exhaust valve seat and seat inserts.
131 is not an octane booster but a cleaner, acid neutralizer, lubricant, and has some seal conditioning properties. It is so passive it will not affect the throw away coffee cups if poured and left sitting in it.
The 131c on the other hand only is a soy bean additive that works in gas engines only and is not for diesel fuel. It cannot be used in any other applciation as the 131 does. It's basic design is to clean, and increase the fuel economy of a gas engine.. a used engine, they claim up to 5% better and on a new engine up to 2% improvement. Also, appears to have Up to 40% increase in fuel lubricity. I'm not all that up on this one as it is more expensive but also is more concentrate.
Hope that helps.
[ February 18, 2003, 06:25 PM: Message edited by: BOBISTHEOILGUY ]