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10 Cars That Faked Their Horsepower Ratings

For Better Or Worse, These Models Published The Wrong Horsepower Rating

A car with the wrong horsepower rating isn’t any different than candy with inaccurate calorie information. Well, maybe in theory, but not so much in practice. Mostly because a few additional horsepower often cost way, way more than a few extra (or a few less) calories.

Carmakers have often reported lower power output figures than their cars actually delivered in the past. That practice saved a lot of money both for them and to the buyers. It was seemingly the easiest way to cheat both the EPA and insurance houses, and outmaneuver their newly imposed taxes on emissions and horsepower ratings. Moreover, manufacturers often adjusted the horsepower in order to achieve more favorable NHRA drag classification. They didn’t lie, however. They only measured power in conditions that were often far from perfect.

And there were numerous ways to do so. One such trick, for instance, was measuring the peak horsepower below maximum engine speed or decreasing the RPM. If a carmaker wanted to achieve the opposite effect, they would simply measure hp at the crank instead of wheels or use the open-exhaust system. Combinations are plentiful and one only needs readjusting one of the parameters in order to tweak the final figures.

Whether it’s the lower or higher horsepower than advertised, such examples are abundant. However, underrated cars are way more common than those that are overrated, so here are 10 such examples. And, before you ask: “No, there are no muscle cars on this list!” We’ve covered that one before.

Any Japanese Car With 276 HP

Years: 1989-2005

In what came to be known as automotive version of the “Gentlemen’s Agreement,” Japanese manufacturers decided to limit all of their domestic models to the maximum of 276 horsepower. The reason: they wanted to avoid the horsepower war in a country shackled by rather strict speed limitations. This is the reason why you won’t find a Nissan Skyline GT-R with more than 276 hp although R34 easily made more than 320 ponies. The R33 and R32 also pushed north of 276 hp, and so did the R34’s successor – the V35 Skyline (G35 Infiniti). Other such examples are numerous Mitsubishi Lancer Evos, Subaru Impreza WRXs, the Toyota Supra 2.5L 1JZ-GTE and 3.0L 2JZ-GTE, the third gen Mazda RX-7, etc.

All of these Japanese sports cars made more than advertised 276 hp. And then came the late 2004 when Honda finally broke the agreement. Then new 2005 Honda Legend (Acura RL in the US) was advertised with 290 ponies. Although oathbreaker of sorts, Honda at least chose the right model to dissolve the agreement. You simply can’t point a finger at something called Legend, can you? Not that the rest of the pack felt deceived. All Japanese manufacturers wholeheartedly jumped in on the 300-hp wagon which was sort of a forbidden fruit for them, for way too long.

BMW M5 (F10)

Years: 2011-Present

The current F10 generation BMW M5 officially squeezes out 553 ponies out of its 4.4L twin-turbo mill. This B44TÜ version of the BMW S63 engine uses 10:1 compression ratio and 1.5 bar (almost 22 psi) of boost compared to 9.3:1 compression and 1.3 bar (close to 19 psi) boost of the non-TÜ version of the engine. Moreover, it’s the first BMW M car engine with valvetronic – BMW’s variable valve lift system. Everything would have been just fine hadn’t this setup actually produced north of 600 horses. That’s what people over at iND Distribution claim, at least. They dynoed the stock 2013 BMW M5 and measured no less than 527 hp at the wheels. Add some 15% that went on drivetrain losses and that comes at just north of 600 horsepower. However, 15% rule shouldn’t be adhered to strictly. Every car experiences different drivetrain losses due to different engine, transmission and driveline design.

Ford GT

Years: 2005-2006

4,000 or so lucky Ford GT owners didn’t even know what they were getting themselves into when they pre-ordered the revived motorsports icon over a decade ago. No need to decorate the car with laurels. We all know how good Ford GT is. Those of you that didn’t know it also had a secret, now do. Ford GT and its 5.4L supercharged Modular V8 engine officially generated 550 horsepower and 500 feet-pound of twist. 550 hp is a crank figure in this instance. Numerous dyno tests, however, report more than 550 hp – at the wheels! That’s more than 630 ponies at the crank if universally recognized 15% drivetrain loss gets taken into account. In truth, GT owners have been getting all kinds of crazy numbers at the dyno. It’s all a matter of tune-up and dyno itself, but Ford GT is certainly more capable then Blue Oval wanted us to believe.

Dodge Neon and Caliber SRT-4

Years: 2003-2005, 2008-2009

Maybe not the most obvious of cheaters, but the funky little Dodge Neon SRT-4 also had more to boast with than it showed. And that’s exactly why everyone liked it. Well, not really. The Neon SRT-4 finally reminisced Mopar’s glory years and that’s why it was so popular. 2.4L turbo four was conservatively rated at 215 hp in 2003, and at 230 hp in 2004 and 2005. That alone showcases its potential, but in truth the SRT-4 made all that and more at the wheels – not the crank. Another proof of SRT-4’s underrated nature would be the Dodge Caliber SRT-4 which was rated at 285 hp with very similar setup. Need I say that the Caliber too was underrated? Edmunds crew squeezed out 281 wheel horsepower out of it. Enough said. Sadly, only 25,000 Neon and around 1,000 Caliber SRT-4s have been made, so it’ll soon be an uphill battle obtaining one.

Audi S4 (B8)

Years: 2009-2016

Outgoing performance version of the Audi A4 was intentionally understated from the get-go. German manufacturers often do this with their performance cars in order to avoid high insurance rates that their customers would end up being hit with. It’s a win-win situation as carmakers sell more of their cars and customers pay less for them in the long run. Well, insurance companies lose, but screw them. Anyway, B8 generation Audi S4 officially packs 333 horsepower at the crank through aluminum alloy 3.0L supercharged V6. In real world, it produces somewhere around 330 ponies, but at the wheels. Being all-wheel drive car, it misplaces anywhere near 20% on drivetrain losses which means it actually makes around 400 horses.

Mercedes GLA 45 AMG

Years: 2014-Present

I guess it doesn’t come as a surprise that all of AMG’s engines are more or less underrated. They’re the top of the line in all Mercedes-Benz classes and models, hence they make the most power. Let’s take the smallest AMG engine available – the M133 2.0L in-line turbo four into consideration. When Mercedes-Benz added it to their compact lineup of A, CLA and GLA class, it started out with 355 horses on tap. Mercedes-Benz GLA 45 AMG is currently rated at 375 horsepower, but that’s still far from its true potential. Without any modifications, this potent little four banger delivers 390 hp at the crank as evidenced by Renntech who tested it prior to CLA and GLA class debut in the US. Modify it here and there, and you’ll easily squeeze out much more from it than that.

Saab 9-5 Aero (YS3E)

Years: 2000-2009

Saab is no more sadly, but one simply has to tip the hat to them. The other Swedes were the masters of deception when it comes to horsepower ratings. Most of their vehicles (although there weren’t many of them) were at least slightly underrated. Aero models which were Saab’s way of spelling performance-oriented, were the most understated by far. When Saab 9-5 Aero flagship performance car came out for 2000 model year, it was conservatively rated at 227 hp. 2.3L turbocharged straight four also delivered 270 lb-ft of torque. Between 2002 and 2005 that same engine was rated at 247 hp and at 256 hp until the end of production. In truth, Saab 9-5 Aero delivered even more than that. No wonder since second generation (YS3G) Aero’s 2.8L turbocharged V6 generated “only” 300 ponies.

Porsche 959

Years: 1986-1988

Very limited for a reason. The Porsche 959 was one beast of a sports car back in mid-late eighties. Germans said that its 2.85L twin-turbocharged flat-six managed to produce a whopping 444 hp. And people were sceptical, to say the least? I mean, how could have such a petite engine generate so much power back in the eighties. And, how wrong were they! Porsche 959 didn’t make 444 hp. No. It actually delivered around 500 horsepower with ease.How else would you explain 0 to 60 time of 3.6 seconds. Furthermore, Porsche themselves offered beefed up versions of the 959 with 515 hp, 530 hp and even 585 hp. The moral of the story: “Never trust the Germans!”

Volkswagen Golf GTI Mk VII

Years: 2014-Present

The Volkswagen Golf has been clearly understated since the fifth generation, and probably beyond that even. Never has it been underrated as it is today, however. Take the Mk VII VW Golf GTI for instance. Volkswagen claims 217 horsepower for the base GTI, but dyno figures read north of 260 horses in completely stock cars. When you consider GTI with performance package squeezes 227 hp out of the same 2.0L engine, you’ll see that something doesn’t add up. Moreover, special edition Golf GTI Clubsport generates 261 hp, and the top Golf R almost hits the 300 hp mark – with the same engine again. Furthermore, the GTI should have 258 lb-ft of torque, but the same dyno test says it actually makes 314 lb-ft of torque in completely stock and basic form.

Ferrari F40

Years: 1987-1992

Apart from being one of the best Ferrari‘s ever produced, Ferrari F40 secretly offers more horsepower than Italians made us believe. But there’s a catch. Advertised at 471 horsepower, Ferrari F40 will rarely display more than that. US spec Ferrari has the same 2.9L twin-turbo V8 as its European counterparts, but also comes with the catalytic converter which severely hampers its performance. In fact, most US spec F40’s won’t even match the stated 471 hp, while Euro cars push up as much as 510 horses with ease. That’s the sad truth, but truth nonetheless. Cats have been ruining performance enthusiast’s dreams for 50 years now, and not only in muscle cars either.

About Nikola Potrebić

Despite driving a piece of junk, Nikola still manages to survive the harrowing experience called "A road trip in a Yugo," day in, day out. On the other hand, precious few things move him as muscle cars do. Especially those from the bygone golden era, which makes him wonder why wasn't he born a few decades earlier? Well, at least he's been given the opportunity to enjoy the likes of the Pontiak Aztek, Chrysler PT Cruiser, Fiat Multipla, and other lovely millennials, right? Come to think of it, I'll stick with my Yugo. Thank you very much!