A Second Dyno Test of the 2020 Toyota Supra Sets the Record Straight... or Does It?
More power, no problemby Kirby, on
Ever since Car and Driver strapped the Toyota Supra to a dyno late last month, there’s been a lot of hand-wringing on how much power actually comes out of the sports car’s 3.0-liter turbocharged inline-six-cylinder engine. C&D discovered that the Supra’s engine might actually produce more power than Toyota advertised. A few weeks later, Motor Trend did the same thing and arrived at the same theory. As advertised, Toyota says that the Supra’s turbocharged inline-six cylinder engine can produce 335 horsepower and 365 pound-feet of torque at the crank. But as the results of these two independent tests showed, it seems like Toyota’s newest crown jewel is more powerful than we thought. Or is it? Either way, it’s hard to argue with the fact that since it debuted earlier this year, the Supra is still what everyone wants to talk about.
This isn’t the first time an automaker has understated the output value of cars. BMW is known for doing such a thing, perhaps because it wants prospective BMW owners to get more than what they paid for. Is it a coincidence that the engine that Toyota has in the Supra is sourced from BMW? It probably isn’t because Toyota is responsible for disclosing the Supra’s power output, not BMW. So when it came time to do just that, the Japanese automaker announced that the Supra’s BMW-sourced 3.0-liter turbocharged inline-six cylinder engine produces 335 horsepower and 365 pound-feet of torque. Those are healthy numbers for a performance car like the Supra, except that neither Car and Driver nor Motor Trend arrived at those figures when they performed independent dyno tests on the Supra.
CD was first to take a crack at the Supra on the dyno when it strapped the sports coupé to an all-wheel-drive Dynojet dynamometer in Livernois, Michigan. Surprisingly, the results came to 339 horsepower and 427 pound-feet of torque at the wheels. That’s an important distinction because Toyota’s posted output — 335 ponies and 365 pound-feet of torque — came at the crank, which typically has a higher output because it’s not subjected to the typical driveline and hydraulic losses that result in a loss of 10 to 15 percent of the total output before it arrives at the wheels. So if CD’s test netted 339 horsepower and 427 pound-feet of torque at the wheels, that would mean that the Supra that CD tested could have had as much as 373 to 390 horsepower and 470 to 491 pound-feet of torque at the crank.
The horsepower output is slightly better than Toyota’s announced output, but the torque numbers are unbelievably higher than what you’d expect, especially if it comes from the B58 engine powering the Z4 M40i, which is officially classified at 380 horsepower and 369 pound-feet of torque.
A few weeks later, Motor Trend performed its own dyno test on the Supra, strapping the sports coupé to a Mustang eddy-current chassis dynamometer in Torrance, California. It’s important to note that the Mustang dyno has been labeled at one point or another for returning lower-than-expected power totals. In the case of the Supra, Motor Trend discovered the opposite. The result showed that the Supra was producing 332 horsepower and 387 pound-feet of torque at the wheels. Perform the same expected crack-to-wheel loss calculations of 10 percent and the figures — 364 horsepower and 426 at the crank — are still way beyond Toyota’s announced output.
So, what gives? Did Toyota really understate the output of the Supra? And if so, for what?
First things first. It’s not fair to compare the tests done by Car and Driver and Motor Trend to one another.
They are independent tests that took place in different locations and on different dates.
Both used different dynamometers, too, though it’s also worth pointing out that the torque figures from CD’s test were measured in fifth gear at a 1.32:1 ratio instead of the 1.00:1 ratio in sixth gear — considered as the most efficient area to measure torque — that Motor Trend did. CD measured in fifth gear because it couldn’t hit the redline in sixth gear, thus admitting that "there’s a chance the peak torque output may be slightly inflated." Nevertheless, the two tests that were done independently using different equipment arrived at the same conclusion: the Supra had a surplus in power compared to Toyota’s official numbers.
Without identifying in concrete terms the reasons for the inflated outputs that CD and MT recorded, there are a number of possibilities that could’ve contributed in the seemingly anomalous returns. It’s possible, MT said, that the specific Supra they tested — it was a press loaner — was an “early build pre-production car with a partial hand-build engine.” That would explain the possibility that the engine hasn’t been calibrated to the specific output that Toyota wants. On the flip side, CD surmised that the transmission’s torque converter “likely isn’t fully locked until higher in the rev range,” contributing to the magazine’s difficulty in hitting the rev line in sixth gear.
There are so many variables to consider that it’s difficult to really assign a reason for the significant discrepancy between the two independent tests and Toyota’s actual figures. Is it possible, then, that Toyota intentionally made the Supra look less powerful than it really is? Related to that, is it possible that Toyota did this to make the BMW Z4 look more powerful? My colleague, Robert Moore, touched on this after Car and Driver conducted its dyno test on the Supra.
For a little perspective, the BMW Z4, which uses the same engine as the Supra, is rated at 382 horsepower and 369 pound-feet of torque.
The Supra, on the other hand, produces 335 horsepower and 365 pound-feet of torque. Now, it’s important to point out that these posted output numbers represent the engine’s output at the crank where transitional losses in the transmission, driveshaft, and rear axle have yet to happen. That happens when the power goes to the wheels. Now, numbers posted by CD and MT after their respective dyno tests point to output numbers at the wheels when all the losses have already taken place. And yet, those numbers are a lot higher than Toyota’s official output at the crank.
Perhaps this was Toyota’s way of placating to BMW so that the latter’s sports roadster, the Z4, doesn’t get probed under the microscope for having less power than its Japanese counterpart. Then again, maybe BMW is underselling the Z4 Roadster’s output, too. Either way, these numbers point to one possibility that should excite future owners of the all-new Supra.
It’s possibly more powerful than Toyota claims it is.
That spells a lot of exciting possibilities moving forward, particularly in the aftermarket world where the Supra suddenly becomes a more desirable donor car that it’s already pegged to be.
There’s a possibility that more tests will be done, too, to really establish how much power the Supra’s B58 engine really has. On that end, I’m looking forward to these tests, not because I want to know what the actual numbers are, but because I want to believe that there’s more — a lot more — than meets the eye when it comes to Toyota’s latest sports car.
Performance And Drivetrain Specs
|2020 Toyota Supra||2019 BMW Z4 M40i||2019 BMW Z4 sDrive30i|
|Engine||turbo 3.0-liter six-cylinder||turbo 3.0-liter six-cylinder||turbo 2.0-liter four-cylinder|
|Transmission||eight-speed automatic||eight-speed automatic||eight-speed automatic|
|Horsepower||335 hp||382 hp||255 hp|
|Torque||365 lb-ft||369 lb-ft||295 lb-ft|
|0-60 mph||4.1 seconds||3.9 seconds||5.2 seconds|
|Top Speed||155 mph||155 mph||155 mph|
|Weight (lb) Per Horsepower||10.14||9.01||12.89|
Read our full driven review on the 2020 Toyota Supra.
Read our review of the 2020 Toyota Supra
Read our full review on the 2019 BMW Z4.