Will Premium Gas Make This SUV Quicker? We Test and Find Out

Curiosity got the better of us with this one. The promise of premium gas beckons enthusiasts everywhere, and we had to know whether pumping higher-octane fuel improves performance. We put this query to the test with our yearlong 2023 Mazda CX-50 test SUV, whose turbocharged engine is good for 227 hp and 310 lb-ft of torque—except when it isn't. Filling up with 93 octane boosts horsepower to 256, and torque jumps to 320 lb-ft. So we headed to the track. Would the CX-50's track-tested 0-60-mph acceleration change, or are you better off sticking with the cheap stuff?

Usually when a manufacturer lists two octane-based ratings, the engine is fitted with a turbo or supercharger capable of cramming more air into the cylinders, and it's programmed to increase the boost and spark advance until the engine senses knock (which indicates harmful predetonation). Higher-octane fuels resist knock better, allowing more boost and/or advance and hence more power and torque. Naturally aspirated engines can only advance the spark and maybe valve timing a bit, and this can't alter power as much.

Mazda isn't the only automaker to provide different power and torque figures depending on the gas you use, but its "up to 256 hp" language made us wonder whether premium gas is worth it. Mazda only provides different figures for the upgrade engine, a 2.5-liter turbocharged inline-four. Pick a trim with the standard naturally aspirated four, and there is only one set of numbers: 187 hp and 186 lb-ft. No matter the engine, all CX-50s come standard with a six-speed automatic and all-wheel drive.

Someone who spends thousands of dollars on a 2023 CX-50 2.5 Turbo trim is probably after more than just features, as most of the same equipment is available on the lower-cost 2.5 S trims. A 2.5 Turbo buyer might also care about the sound and superior acceleration offered by that turbo. We've tested the standard CX-50 hitting 0-60 mph in 8.5 seconds, while the more powerful CX-50 2.5 Turbo like our yearlong test SUV reaches that benchmark speed in 7.0 seconds.

That's a significant 1.5-second drop from one engine to another, but the 2.5 Turbo engine has left us wanting even swifter acceleration for our money. The engine sounds great under moderate to heavy throttle, but more power or a quicker-shifting transmission would really help.

One other note about our results: We conducted this 2023 Mazda CX-50 test in California where 91 octane is the max. You might have slightly better results with 93, which is where Mazda gets the 256 hp and 320 lb-ft figures.

This wasn't what we expected. In MotorTrend's track testing of our CX-50 2.5 Turbo on 91 octane, the Mazda hit 60 mph in just 6.6 seconds. Not bad at all. That's a 0.4-second improvement over the same SUV tested with 87-octane fuel. For some, that alone might make premium gas worth it. The 91-octaned CX-50 2.5 Turbo finished the quarter mile in 15.1 seconds at 91.3 mph compared to the same SUV with 87 taking 15.4 seconds at 89.7 mph.

Looking deeper into the data, road test editor Chris Walton told us that most of the gain was in the 0-30-mph range. This is good news for lead-footed drivers because it means you might be able to feel a difference even on an empty city street. Driven back to back, 87 to 91 or 93, you might notice something, but otherwise it would be harder to discern any change. However, if you're OK riding on principle alone, just knowing it's quicker could make it a good investment.

Speaking of investments, here's how much this 0-60-mph improvement will cost you. If you drive 12,000 miles a year and spend 55 percent of your time in city driving and the rest on highways (at highway speeds), you'll spend $389 more every year on gas—and that's assuming you drive the same way most of the time on either fuel. Frequent jackrabbit starts to "get your money's worth" will add to that tally. These numbers are based on the average gas prices in the U.S. at the time of writing, which is $3.44 for regular and $4.25 for premium.

We appreciate the improvement in acceleration upgrading to premium gas. Every engine is different, but it's nice to know you have an option with the CX-50 2.5 Turbo: decent acceleration with savings on fuel or better acceleration for those who've gotta have the best. Mazda says you shouldn't expect noticeably different fuel economy with one type of gas over the other, though the CX-50 driver who spends more on premium gas may find themselves pressing farther into the accelerator pedal's travel than the driver who chooses 87.

The accelerative improvement is not worth it for me—I'd probably save the money. Thousands of miles have shown us that although the 2023 Mazda CX-50 is a solid compact SUV, acceleration and fuel economy are just not among its strengths. But hey, if your road trip ever calls for a full 256 hp instead of just 227, you know what to expect if you fill up with the good stuff.

For More On Our Long-Term 2023 Mazda CX-50 Turbo: