Savage Mustang Goes Stealth Mode with ‘Hideaway’ Twin Turbos

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Making a sleeper out of a street bruiser is fun, especially when your setup looks completely stock under the hood.

Fans of the S550 Mustang are truly living their best lives. Where else can you find a car capable of ripping off 700-plus hp and high 9- or low 10-second quarter-miles with the simple addition of a power adder? There are numerous options out there as well, each catering to your specific speed needs.

One of the newest, and most awesome, is Hellion’s Street Sleeper twin-turbo setup, as seen on their official YouTube page. The budget-priced kit is available with a wide range of options, but the premise is very unique. Instead of mounting the turbos in front of, to the side, or on top of the engine, this kit positions them underneath the car. Thus, when you pop the hood, you see nothing but stock components.

S550 Mustang Hellion Street Sleeper Turbo Kit

The inherent design of the Street Sleeper kit is pretty ingenious as well. As our host points out during the installation, a lot of thought went into making it not just a great power adder, but also a reliable one. “One of the problems with any low mount system that uses oil-fed turbos is the oil system,” he says. “A lot of people over the years have fought smoking issues. Most people use electric pumps, but Hellion addressed this problem with a mechanical oil pump. It’s a foolproof system.”

S550 Mustang Hellion Street Sleeper Turbo Kit

But just because Hellion’s Street Sleeper setup does things differently doesn’t mean that it isn’t incredibly capable. That fact is on fully display in this dyno test video from renowned S550 tuner Palm Beach Dyno. In this case, the customer chose to go with 6266 Precision turbos, which should give him quite the boost. Pun intended.

S550 Mustang Hellion Street Sleeper Turbo Kit

On pump gas (93 octane), the 2015 Mustang put out 650 hp and 603 lb-ft with just a base tune. After some tweaking from PBD, those numbers increase to 663 hp and 610 lb-ft. Which proves two things. One, the Hellion base tune is pretty darn good. Two, you don’t have to have top-mounted turbos to go fast in an S550 Mustang.

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Brett Foote has been covering the auto industry for over five years and is a longtime contributor to Internet Brands’ popular Auto Group websites, including Corvette Forum, Rennlist, and Ford Truck Enthusiasts, among others.

Foote has been an automotive enthusiast since the day he came into this world and rode home from the hospital in a first-gen Mustang, and he's been wrenching on them nearly as long.

In addition to his expertise writing about cars, trucks, motorcycles and every other type of automobile, Foote had spent several years running parts for local dealerships.

You can follow along with his builds and various automotive shenanigans on Instagram: @bfoote.

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