If you've upgraded to macOS Mojave or later, follow these steps to keep it up to date: How to get updates for macOS Mojave or later I gain 4rwhp at 2500rpm so you do not lose low end tq with a h-pipe. Ok I dyno the Mach 1 today with the o/r h-pipe it made 303rwhp & 323tq.
New Dyno For Mac Average ratng: 9,8/10 928 reviews
