Hennessey Performance is teasing their latest upgrade package for the McLaren 720S in a new dyno video.
We knew this was coming. Two weeks after Hennessey released a video of them testing a stock McLaren 720S we get our first taste of what they had in store for that British supercar. And as expected, it’s a whole lot of power.
They call it the HPE900 McLaren 720S upgrade, and as Hennessey’s naming conventions imply, it’s got 900 horsepower at the crank. Getting to that much power involved replacing the air filters with high-flow versions, recalibrating the factory ECU, replacing the exhaust with a new stainless steel system, an upgraded intercooler, and unspecified upgrades to the factory turbos.
Of course, there’s the usual assortment of Hennessey emblems and plaques to go along with it, as well as the standard 3-year or 36,000-mile warranty.
Hennessey isn’t known for their efficient upgrade packages, however, so dyno testing reveals just how many of those 900 horses actually make it to the rear wheels. Surprisingly, rear-wheel horsepower is rated at 809--just 10% power loss. That’s not quite as good as the stock models 675 rear wheel horsepower, which is just 5% power loss to the transmission, but still pretty good.
Hennessey might have also performed some undisclosed upgrades. The stock 720S is a rear-wheel-drive vehicle, while this car seems to have all four wheels spinning during the dyno test. Could Hennessey have given the 720S all-wheel-drive and forgotten to mention it? And what’s with the odd shudder at the end of each pull? There are still many questions for Hennessey to answer here.
We’ll have to wait for those answers. Pricing and availability have not yet been announced, and neither have any performance figures. We do know that Hennessey plans to offer an HPE800 and HPE1000 upgrade for the 720S, with varying amounts of tweaks to each car’s guts. We’ll be sure to report on those as soon as we hear more.