Excellent Overkill: Adding Twin Turbo Power to an Already Supercharged Mustang

When it comes to building lots of horsepower with power-adders, there are some people that are firmly devoted to superchargers with tons of torque and on-demand power. On the other side are the fans of turbos with their greater efficiency despite a little lag.

And then there are the freaks that have decided the only way to get the best of both worlds is to use both on the same engine. One of those freaks—and we mean that in the best way—is Hellion Power Systems, which has developed a kit that allows you to easily add twin superchargers to 2007 through 2009 supercharged Ford Mustangs.

Hellion’s twin turbo kit is the first produced in the United States for the Mustangs and works with either the factory supercharger, aftermarket superchargers or no supercharger at all with an optional sheetmetal intake. The idea of adding a turbo—or two turbos as is the case here—is called compound boost and it creates the best of both worlds. To get the same power you could just crank up the boost on a supercharger, but then you’re talking about a lot of horsepower wasted to spin the supercharger and you are also creating a lot of heat. You could also do the same thing with turbos, but making big power often means big turbos and that usually means the appearance of dreaded turbo lag.

One of the best features of the Hellion twin turbo kit is it is completely bolt on. It’s not only easy to install, it’s also easily removed. That’s why Scott Derrickson, the owner of Extreme Mustangs, decided to install the kit on his own car. Derrickson drives a 2009 Shelby Cobra. The car is not only valuable now, but it likely will only grow in value in the future. The Hellion kit doesn’t require chopping up the car, so if Derrickson ever wants to return the Shelby to its original stock form, all that’s required is to unbolt the components and reinstall the cats.

Another part of this kit that really caught our fancy is it is completely out of sight. Both turbos mount up approximately level with the frame rails. A quick glance under the hood reveals nothing, making this twin turbo kit a real sleeper. If you are the kind of guy, or girl, that prefers to talk softly but carry a big (horsepower) stick, this will definitely get your interest. After installation, Derrickson took the car to Pro-Dyno for tuning and they were able to safely crank out 741 horsepower and 743 lb/ft of torque from this combination at 17 pounds of total boost.

Download the Resource List for this build.

Download the printable Dyno Sheet for this build.

Photo 01—The subject for this install is the Extreme Mustangs house car, a 2009 Shelby Cobra. Definitely a nice car to begin with, and a monster when you add twin turbos to the already supercharged engine.

Photo 02—There is a lot more included in the kit than this, but the foundation of the system are the two Turbonetics 61mm turbos, two Turbosmart Ultragate waste gates, and the TurboXS Race bypass valve.

Photo 03—The foundation for this project is Ford’s four-valve supercharged Modular engine. Derrickson has already added a cold-air intake, which will be removed in favor of the turbo system.

Photo 04—The first step is to remove the exhaust system from the catalytic converters on back. Having a lift like this does make life a lot easier, but you can perform this install in your driveway with your car on jack stands just as well.

Photo 05—After pulling the oxygen sensors, measure 10 inches back from the weld on the cats and cut them off. This space will be filled by the turbos. Now the rest of the exhaust can be reinstalled with the flanges supplied by Hellion.

Photo 06—Here’s a shot of how all the exhaust plumbing bolts up ready for the turbos. Notice the O2 sensors have been reinstalled.

Photo 07—You will need to remove the oil pressure sending unit, which is located next to the oil filter, and install the oil distribution block in its place. The lines from the distribution block will feed the turbos.

Photo 08—This is the scavenge pump assembly that pulls the oil from the turbos. It uses a bracket that allows it to be installed against the K-member.

Photo 09—The turbos Hellion spec’ed out for this kit are twin 61 mm units from Turbonetics which should provide both plenty of power and trouble-free durability.

Photo 10—Loosen all the bolts around the turbo’s exhaust and compressor housings and install it on the car. Now clock the turbo so that the oil drain flange is on the bottom of the turbo and pointed toward the center of the car.

Photo 11—Before everything is tightened down, make sure the boost tubes match up properly.

Photo 12—Silicone sleeves between the turbo outlet and the boost tube helps eliminate cracking and wear from vibrations.

Photo 13—Once everything is situated correctly, Derickson tightens down all the bolts.

Photo 14—Greg Troutman hooks up the oil feed lines to the top of the turbos and the return lines to the bottom. It’s always a good idea to keep the lengths of the two return lines as close to equal as possible to make sure the pump pulls from both turbos equally.

Photo 15—Both turbos have been installed with the oil return lines routed toward the pump. Notice how they tuck up cleanly underneath the car so that they are safe from speed bumps and other road hazards.

Photo 16—Here’s how the return lines plumb up to the pump. That large diameter hose you see above the lines is the intake feeding the turbo. A filter will be added later.

Photo 17—Both turbos are fed air through K&N filters that are hidden up out of the way so that they won’t pull water if you have to drive through large, or deep, water puddles.

Photo 18—The waste gates are installed along with the supplied vacuum lines from the waste gates to the fittings on the compressor side of the turbos.

Photo 19—Derrickson routes the supplied boost tubes through to the top side of the car where it can feed the supercharger.

Photo 20—Up top this oil return block installs on the valvecover and allows a return inlet for the oil from the scavenge pump.

Photo 21—On the other side, the supplied K&N breather is installed on the valvecover.

Photo 22—Hellion also includes a set of turbo-ready NGK spark plugs. Before installation, Derickson makes sure each is precisely gapped to 0.030 of an inch.

Photo 23—The blow-off valve attaches to a port on the boost tube just before the supercharger.

Photo 24—The Hellion system uses its own fuse pack. Derickson installs it on top of the Ford’s fuse box.

Photo 25—Derickson also added a Greddy boost controller to allow easy tuning adjustments.

Photo 26—The added boost of the twin turbos will peg the stock boost meter, so a Mafia boost extender is also added.

Photo 27—This idiot light is provided by Hellion and is wired to warn you in case the scavenge pump fails.

Photo 28—After checking back over everything, Derickson uses an SCT tuner to put a mild tune on the engine so that he can safely drive the car to the chassis dyno for a more aggressive tune.

Photo 29—The finished install, and it was definitely worth the trouble. After tuning the system puts out 741 horsepower and 744 lb/ft of torque at the rear wheels.

6 Responses

  1. CarArt
    That's a ton of info! How long does the install take?
  2. It was about a day and a half for the install and then another half day for the dyno tuning. I'd allow a good weekend or more for the install if you are trying to do it yourself.
  3. Nice topic - respect !
  4. eToro
    Now streetmuscleaction.com is one of my fav websites
  5. Jeff - I know this article is a bit dated, but I am looking into twincharging an XLR-V and wanted to know what you thought about the general driveability of this auto once the above mentioned modifications were performed? No additional fuel required? Was the car making the power mentioned in your write-up on pump fuel? Do you know if the car is still on the road? I wonder what kind of intake temperatures they saw and if they ever considered an air to air intercooler. Any thing you can offer up in personal impressions would be helpful.. Thank you sir.
  6. I have a Mercedes SL55 AMG I really would like to have a system like this on my car, is there any way that you can get a system for my Mercedes an how much is the cost, if you can get it for the complete system......Think you.......if not do you know where I can get a dual turbo system for my car I been looking all over for one an can not fine one any where for this SL 55 AMG.

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