The 35hp Vanguard engine uses 1.6 gph on my Scag Turf Tigers. I had a Kohler 25hp on a Scag Tiger Cub 52" that used the same amount. Also ran a BB Outlaw with 54" deck last year 31 Kawi that used 2.0 gph. Last year I demoed a 930 60" deck with a 29hp for 40 hours for 8 days. It used 2.2 gph..... I would hate to even try the 37 Kawi. Hopefully JD will have the Vanguard as an option some day. Until then I can't afford to run them with the amount of hours I run my machines per year. I do think it is an awesome machine with a deck that rivals the Scag Velocity Plus deck.