When it comes to full-size luxury sport utility vehicles, you're presented with a ton of choices. Over at BMW and Mercedes-Benz, for example, prospective customers are offered either the X7 or the GLS with a varied selection of powertrains.
Both of them sport inline sixers as standard or optional V8s. Pictured at the Dunville Autodrome in Canada, the X7 M60i and GLS 580 in the featured clip are twin-turbo eighters with similar power and torque, yet one of them is more special than the other. The special one is the S68 in the X7 M60i, the S prefix being specific to BMW M.
Regarding the GLS 580, the German automaker dubs the mild-hybrid engine M176. As opposed to the M177 and M178, which are individually assembled in Affalterbach, the M176 is mostly assembled by machine at Unterturkheim. Following the discontinuation of the first-generation GT, the M178 is – for the time being – exclusive to the Aston Martin Valhalla mid-engine supercar.
It's also worth noting that M176s and M177s are wet sump as opposed to the dry sump lubrication system of the M178. As for the S63-replacing S68, the latest and probably the last V8 from the M division was designed with electrification in mind. That's why the BMW engine is also used in the XM. Come model year 2025, in the all-new M5 as well.
In this particular application, the S68 is much obliged to deliver 523 horsepower (530 ps) and 553 pound-feet (750 Nm) of torque. On paper, that is, because the S68 is known to make a wee bit more than officially advertised. The non-AMG M176 of the GLS 580, by comparison, produces a respectable 510 horsepower (517 ps) and 538 pound-feet (730 Nm) from 4.0 liters as opposed to 4.4 for the Munich-based automaker's TT V8.
Photo: Sam CarLegion on YouTube
Engine specs aren't enough to determine which of these family-sized luxury SUVs is faster in the quarter mile. In terms of cog-swapping contraptions, we're dealing with the ZF 8HP in the Bimmer and the 9G-TRONIC in the Merc. Weight? Make that 5,820 pounds or 2,639 kilograms for the GLS 580 versus 5,895/2,673 for the X7 M60i.
Tire choice, launch control calibration, weather, and – of course – the driver also make a world of difference in the quarter mile, but alas, the X7 M60i proved faster than the GLS 580 three times on the trot. Their bests were 12.5 and 12.7 seconds, respectively, with 60 miles per hour (97 kilometers per hour) coming in 4.0 and 4.2 seconds.
From a rolling start, the gap is larger still. Sam CarLegion hasn't provided any times, but from the footage below, it's easy to see how much faster the X7 M60i is from either 37 or 50 miles per hour (that would be 60 or 80 kph in the metric system).
At the moment of reporting, the GLS 580 is decidedly pricier at $112,000 before destination and optional extras. The sportier X7 M60i retails at $110,900 for model year 2025, and BMW claims a rather conservative 4.5 seconds to 60 mph.
After a 1:43 scale model of a Ferrari 250 GTO sparked Mircea's interest for cars when he was a kid, an early internship at Top Gear sealed his career path. He's most interested in muscle cars and American trucks, but he takes a passing interest in quirky kei cars as well. Full profile
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