Muscle Mustangs & Fast FordsHow To Engine
From Grandma Grocery Getter to Hell Raiser
A Hellion turbo system turns a stock 5-liter Mustang into a fire-breathing street beast.
Just saying the word turbo conjures up thoughts of big power and great performance. One look at today's heads-up Mustang drag racing scene confirms those feelings. In the past, however, putting a turbo setup on your street-oriented Mustang was complicated and could become overly expensive.
But as turbos have become more mainstream, several companies have stepped up to offer bolt-on kits for 5-liter and 4.6-liter engines, taking the special fabrication and custom piping out of your hands. Transforming complicated fabrication into an easy-to-install kit puts these systems at a bit higher price than most centrifugal superchargers, but the results are awesome and definitely outweigh the extra cost. One of the new players in the market is Hellion Power Systems, started by noted Mustang drag racer John Urist.
We went to Hellion headquarters in New Mexico to get the scoop on the company's new lineup of turbo systems for Mustangs, and to cover the installation of the standard 5-liter Hellion kit. The parts list is quite long; 73 components are listed in the instructions. Despite that vast number, though, the installation was straightforward and can be completed in a day.
A Turbonetics 62mm turbo unit comes standard along with the large air-to-air intercooler (which was specifically designed for the kit). Hellion offers several turbo upgrades as well as other options like catalytic converters, a turbo blanket, and so on. We suggest you check the Web site (www.hellionpowersystems.com) for each upgrade and associated cost. Another great feature of this system is that Hellion has all the parts in stock, ready to ship. The staff will get your kit out within 24 hours of the downpayment.
Dropping a turbo kit on your Mustang will provide a serious step up in performance. Our test vehicle was a stock '92 Mustang--right down to the air filter. In this trim, it turned the rollers on Speed Dream's chassis dyno to the tune of 190 rwhp and 275 rwtq. With the Hellion kit installed and producing a rather conservative 9 psi of boost, the '92 LX kicked out an impressive 392.4 rwhp and a maximum rear wheel torque reading of 487.1 lb-ft. This was accomplished with a stock computer and manual tuning of fuel pressure and timing.
To help the car idle properly, we simply rotated the MAF sensor. Urist stated that turning the housing in a blow-through application changes how the meter reads the incoming air. Sure enough, he was correct; rotating the meter toward the outer fender made the engine idle leaner, while rotating it inward toward the engine caused the computer to richen the idle mixture. We saw it firsthand with the air/fuel ratio meter on Speed Dreams' dyno. It's all about how the air hits the sample tube.
Through trial and error on the chassis dyno, we found the optimum fuel pressure to be 32 psi with the vacuum line disconnected. Timing was set at a mild 23 total degrees. After repeated attempts to better the power output with different adjustments, we found those to be optimum on our Stang. The drop-top registered an air/fuel ratio of about 11.6:1 through most of its best dyno performance.
Like true boost junkies, we just had to see what our little test Stang could do with more boost. So Urist disconnected the vacuum line to the wastegate, essentially jumping the boost pressure to its max. It was like pulling the pin on a grenade--we knew it would blow, but how long could it last? Unfortunately, we didn't even get a full chassis dyno run from the car before she kicked the head gaskets. The boost gauge swept--almost instantly--to a whopping 18 psi of boost and then--boom! Speed Dreams' super-clean chassis dyno room was covered with an antifreeze/water mix. The 91 octane was definitely the source of the detonation, thanks to the high boost.
In hindsight, pushing out the head gaskets was a blessing in disguise. Dwayne James of Hellion had a set of brand-new AFR 185 heads and a TFS Street Heat intake manifold sitting at home. The free-flowing cylinder heads went on the stock short-block and were sealed with a set of Cometic head gaskets. Improving the induction jumped the power output from 390/494 to an impressive 465 rwhp and a ground-pounding 517 lb-ft of torque, also at the back tires. Urist kept the stock camshaft in place to maintain a mild idle and keep the sedate-looking LX a sleeper.
When compared to the stock engine output, we picked up nearly 200 rwhp and over 200 lb-ft of torque while running a mild 9-psi of boost from Hellion's 5-liter kit. And that was before the head and intake manifold were installed. The myths about turbos are true--they're fun and make awesome power. And we like them even more now since they're readily available and easy to install.