And that's while running on pump gas.

Hennessey Performance Engineering, otherwise known as HPE or just Hennessey, has become synonymous with tuned American cars with whopping power outputs. That's because the popular tuner is fond and became known for tuning practically Detroit's Big Three – Ford, GM, and FCA.

In fact, looking through Hennessey's website, you'll find that most of the names on its catalog are American brands – except for McLaren, the planned Porsche Taycan, and this, the Audi R8.

Gallery: Hennessey Audi R8 HPE900 Twin Turbo Upgrade

By all means, the R8's default naturally-aspirated 5.2L V10 isn't a slouch; the Performance Quattro version can make 612 horsepower (456 kilowatts) and 428 pound-feet (580 Newton-meters) of torque. These numbers can propel the R8 from 0 to 62 miles per hour (100 kilometers per hour) in just 3.1 seconds

With a Hennessey's HPE900 twin-turbo performance upgrade, however, the goal is to boost the R8's output to 912 hp (680 kW) at 7,400 rpm. This was done by adding two Precision twin ball-bearing turbochargers. The video on top of this page shows the Hennessey Audi R8 on the dyno, which makes 752 hp (561 kW) on four wheels and 545 lb-ft (739 Nm) of torque at the rear wheels. Not bad. Not bad at all.

Hennessey says that only 6 PSI of boost was applied to the R8 on the dyno and it still uses pump gasoline. The engine, fuel system, and transmission are all stock, as well.

By the way, Hennessey also offers the same HPE900 upgrade to the R8's platform brother, the Lamborghini Huracan. There are no details yet for this upgrade but of course, you can't expect anything less from the Texas-based tuner.

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