In the early '40s, the U.S. government-along with Canada and Great Britain-embarked on a mission to create a new type of weapon. The Manhattan Project was formed to research the splitting of an atom in order to create an explosion that the world had never seen. Atomic energy was neither a new concept nor one that hadn't been researched before the Manhattan Project was started. The Germans had been researching atomic power as an alternative source of energy since the late '30s. It was a race to see who could develop the technology quicker.
Compounding boost is simple. Just have two turbochargers blowing into a supercharger. The result of our testing was 1,188 rwhp and 1,015 rwtq.
Moving forward to today's high-performance Mustang world, the race for speed and more power has brought about a project at Hellion Power Systems (Albuquerque, New Mexico)-developed under the same veil of secrecy as the Manhattan Project in nearby Los Alamos. The company has developed a new kind of turbo system to battle the GM and Mopar contingents as well as further pull away from the sport compacts and outrun the crotch rockets. They kept the project secret in order to develop and perfect the turbo system before the public got a glimpse of it. Once the bugs were worked out, they invited us to witness this new system firsthand.
Hellion's new modular-motor turbo system has a pair of turbochargers that blow into a super-charged '03 Cobra engine-utilizing a concept called compound boost. It's not a new term as, "diesel engines have used turbos on top of super-chargers since the '60s," according to Hellion's John Urist. Over the past six months, he has been collaborating with Dave Austin, head engineer at Turbonetics, on the possibility and effectiveness of this setup. The discussions centered on pres-sure ratios created by compounding stages of compressors and how it relates to performance. Austin has vast knowledge on the topic, and even cited a project in the '80s he worked on with Jim Feuling and Jerry Magnuson that had a turbo huffing into a Roots-type supercharger.
Compound boost is a term that is quite common outside the Mustang world. The typical compound boost setup is to have one turbocharger-usually a large one-blowing into a smaller turbo, much like the latest 6.4L Power Stroke. It helps generate serious low-end torque and still breathes easily upstairs. Another benefit is that it allows high boost pressures without high turbo speeds, keeping the compressors in a more efficient range. Compounding boost in diesel engines has also been accomplished with a turbo blowing into a supercharger. We've also seen it perform on a smaller scale in the sport-compact world. Volkswagen is coming to market with a 1.4-liter engine that will feature a turbo blowing into a supercharger induction system.
Urist took it one step further and has run Hellion's new twin-turbo kit into the blower. It created shocking results that will have even the most hard-core guys asking when is enough, enough? Hellion is set to hit the market with twin-turbo systems for all '96-'04 modular engines, including Two-Valve and Four-Valve combos.
The kit featured here is universal and can be used with a supercharger or without it-the difference will be in the turbocharger sizing to fit different applications. The piping and turbo mounting is universal in all systems and mod-motor applications. For those brave enough and in need of the excess, check out the turbo/ supercharger system. It will not disappoint your appetite for ridiculous power levels. We watched this setup throw out a certifiably insane 1,188 rwhp and an even more impressive 1,015 rwtq-through a stock engine including the factory cast-iron exhaust manifolds.
From the topside, it doesn't look too abnormal, save for the giant MAF sensor and inlet pipe. The return-style fuel system and large fuel injectors are also a dead giveaway that something serious lurks within. | 
Two Turbonetics ball-bearing turbochargers are included in the modular twin-turbo system; sizing depends on the application. For those running the supercharger/turbocharger Hell Raiser kit, a pair of 66mm turbos are included. | 
The turbos mount on either side of the bumper and blow into an air-to-air intercooler. The intercooler is located behind the black heat exchanger that sits under the bumper. One would think the intercooler would have an airflow problem with it behind the heat exchanger, but John Urist says testing proved the cooling capabilities were not affected. |
You can see how the exhaust piping is routed from the stock exhaust manifolds to the turbos and then to the Bassani after-cat exhaust system. | 
Information is important when testing a new combination, and Urist didn't mess around. He had Mike Abdalla wire in a Race Pak datalogger to keep an eye on many different parameters, including two boost gauges to monitor turbo and manifold boost levels. The purple box is the PMS engine-management system. | 
A Maximum Motorsports tubular K-member, A-arms, and coilover struts were installed on this Cobra. An aftermarket K-member is required, and Hellion includes a UPR K-member standard in all kits. Hellion offers Maximum Motorsports' K-member as an option. |