Last year, the Stellantis-owned brand Alfa Romeo revised its hybrid Junior model’s power figures upward just before its launch from 237 horsepower to 278. Somehow, after development, the Italian brand found an extra 39 hp and just in time to wheel it out in front of the world. Now, the French brand has found extra power in its plug-in hybrid (PHEV) Citroen C5 Aircross, raising it from 192 hp to 222 hp.
Powertrain Math Is Hard
Citroen
Individually, the two power sources in the plug-in hybrid Citroen C5 Aircross make the same amount of power individually – the four-cylinder gas engine makes 148 hp and the electric motor generates 123 hp. But, despite no engine revision, added hardware, or upgrades in general, Stellantis has measured an extra 39 hp when the two are combined. According to Carscoops, Stellantis says the new rating “is more accurate in terms of the performance offered by this engine and is consistent with the declarations observed on the market.”
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The confusing bit here is that modern technology is incredibly accurate at measuring outputs, and there’s a simple equation to work out the power measurement with a car on a chassis dyno. And there are standard methods depending on where in the world they are taken, but the takeaway is it measures total power that ultimately reaches the ground. Manufacturers also typically use engine dynos to get power ratings at the crankshaft, before the parasitic power loss.
Consistent With Declarations
Citroen C5 Aircross
However, the electric motor isn’t connected to the crankshaft, which appears to give automakers some wiggle room, and it’s not as simple as adding two numbers together. The two outputs, 148 hp and 123 hp, add up to 271 hp. Obviously, that is neither 192 hp nor 222 hp. What raises our eyebrows here is that the new power number is “consistent with the declarations observed on the market.” That could be read a few ways.
We’re choosing to read that Stellantis has been conservative with its mathematical estimates, not that it thinks other brands play a bit loose with the math and overestimate. The company also said the new estimate comes “in anticipation of the protocol that will be applied when the Euro 7 standard comes into force.” That would be interesting as, at face value, its being suggested the new emission standard will help horsepower, not hinder it.
It Won’t Change How The Car Drives
Citroen
With no change to the powertrain between the first output number given and the second, that means that the car won’t be any faster. The powertrain is shared with other brands, including Peugeot, Opel, and Jeep. Specifically for Jeep, the PHEV system used in the Jeep Compass, but not in the US. Here, we only get the four-cylinder engine making 200 hp.
The only difference between the system currently on the road and the new Citroen C5 Aircross is a larger gas tank and updated engine operating logic with energy consumption while maintaining performance. So, presumably, the other models also running the same PHEV system will get upgraded figures soon via some database changes. Maybe even a software update for the new engine operating logic.
Source: Carscoops
