This whole octane vs hp tradeoff seems very slippery to me.
I doubt Mazda has any way to directly measure octane of the fuel supply, so presumably any engine detuning occurs dynamically in response to detecting engine knock. The problem is that engine knock is dependent on many more factors than just fuel octane. So under non-challenging conditions, the engine probably doesn’t knock at all even on 87 (and makes the full 250-HP) while in challenging conditions (I.e., hot weather, heavy loads, high atmospheric pressure) I suspect some detuning might occur even with 93.
I’m guessing that Mazda’s HP derating numbers are some kind of overall average rather than precise outputs. Which means that using premium simply buys you more headroom to be able to make full HP in challenging conditions. Conversely, using regular probably gives you full HP in most conditions.
Doing a track day, towing a trailer over a steep pass, or racing around your favorite canyon roads? You’d probably benefit from premium. But trundling to work in traffic or cruising a flat freeway at 70? No benefit whatsoever. That’s my read of things.
- Mark
I doubt Mazda has any way to directly measure octane of the fuel supply, so presumably any engine detuning occurs dynamically in response to detecting engine knock. The problem is that engine knock is dependent on many more factors than just fuel octane. So under non-challenging conditions, the engine probably doesn’t knock at all even on 87 (and makes the full 250-HP) while in challenging conditions (I.e., hot weather, heavy loads, high atmospheric pressure) I suspect some detuning might occur even with 93.
I’m guessing that Mazda’s HP derating numbers are some kind of overall average rather than precise outputs. Which means that using premium simply buys you more headroom to be able to make full HP in challenging conditions. Conversely, using regular probably gives you full HP in most conditions.
Doing a track day, towing a trailer over a steep pass, or racing around your favorite canyon roads? You’d probably benefit from premium. But trundling to work in traffic or cruising a flat freeway at 70? No benefit whatsoever. That’s my read of things.
- Mark