There’s no doubt that the GR Corolla is an incredibly fun hot hatch. In fact, after driving it last year, we think it’s one of the best things Toyota has done in a long time. Now, one new owner has proven that at least her GR Corolla is making quite a bit more power than Toyota says it should.
Every GR Corolla, regardless of trim level, is factory-rated at 300 hp (223 kW). Keep in mind that rating is referring to how much power the engine makes at the crank, not at the tires. By the time the power gets to the ground, drivetrain losses can reduce that figure by 15-25 percent depending on a number of factors.
In the case of the GR Corolla, a car with a complex AWD system, drivetrain losses are likely a lot closer to that 25 percent mark. So if the car really makes 300 hp at the crank then we can expect about 225 hp (167 kW) to the wheels.
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And that’s important because that’s where almost all dynos including the one in this story, a DynoJet, measure horsepower. Road and Track found one member of the GR Corolla Owners Facebook group who, when they put their car on an AWD dyno, scored a peak power of 258.66 hp (192.88 kW) to the wheels.
Do the drivetrain loss math in reverse and you get what could be some 344.88 hp (256.52 kW) to the crank. In other words, about 13.4 percent more power than Toyota rates it at. There are a number of caveats that need to be covered regarding these figures.
Different dynos produce different results. In fact, two dynos of the same brand could give different ratings for the same car depending on other variables like engine temperature, dynamometer condition, and other factors. On top of that, horsepower ratings can change between dyno runs on the same car.
At the end of the day, we only know that it’s very likely that at least this particular GR Corolla makes more than it’s rated for. Will other tests prove that it’s a condition shared by the majority of the fleet? Only time will tell.
