Is my buggy slow

[BrianG]

That setup calculates to around 55mph, depending on actual tire size. You are getting into the zone where air drag is playing a larger role. You're gonna need to gear higher to compensate for wind drag and a decent area to get up to speed gradually. Gearing high and WOT starts is a recipe for disaster. Make sure your tires are balanced and there is no excessive drivetrain drag (too tight mesh, worn bearings).