Conor McGregor is gonna be PISSSSSED when he finds out how much cash Floyd Mayweather will make from their fight ... at least that's what Floyd's telling people. 

One of those people is UFC champ Tyron Woodley -- who kicked it with Floyd at the Maxim 100 party in L.A. over the weekend.  

In fact, Floyd made a video with Tyron calling him "the best UFC fighter" -- a compliment to Tyron and an obvious diss to McGregor. 

Tyron co-hosted the "TMZ Sports" TV show (airs weeknights on FS1) and said Floyd was super cool during their hangout -- and even offered to give him some private fighting and business lessons. 

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Mayweather also mentioned McGregor ... telling Tyron, "Conor's gonna be pissed when he sees how much money I'm making."

Conor's expecting to make around $100 mil for the fight. Mayweather has previously told TMZ Sports he expects to make 2 to 3 times as much.