KJ Jones
October 15, 2013
Photos By: KJ Jones

Horse Sense: There are several new Mustang parts that meet CARB's strict criteria for receiving Executive Order certification—the board's official blessing (symbolized by a highly coveted number that is placed on a part). This is the story of one CARB-legal system that we think is pretty cool, and it confirms high-performance and the environment really can peacefully coexist!

The United States of America is a great country due to the freedoms its residents are granted by the Constitution. While these and many other rights are important and definitely appreciated by a majority of folks that live here, some of these freedoms are subject to restrictions.

There's no disputing the fact that we all enjoy our right to own, drive, and modify high-performance Mustangs. However, as such freedom goes, street performance mods are at the mercy of each state's government, and the exhaust output of internal combustion engines comes under intense scrutiny by state environmental agencies. In an effort to save our planet, states like California issue stringent regulations on aftermarket parts designed to improve engine airflow. The regs, especially those adopted by the California Air Resources Board, have been the proverbial thorn in the sides of the Golden State's 'Stangbangers and parts vendors.

Kurt’s clean, stock Pony goes by the handle Stealth 5.0, based on its black paint/cockpit/wheels appearance arrangement—a good look indeed, and a perfect platform for Roush Performance’s 2.3-liter smog-legal blower.

Unfortunately, economics drives this wicked catch-22. For manufacturers, CARB compliance carries a hefty cost thanks to the extensive development and testing necessary to gain compliance. Manufacturers quickly admit that it is a difficult balance. When an aftermarket company's costs for CARB compliance are weighed against the market share of California enthusiasts, it's often not a profitable scenario. As such, companies typically choose to not seek CARB approval. Instead they produce performance parts accepted by the 49 other states.

As we all know, a fuel-injected Mustang's engine performance hinges on how efficiently it uses air and fuel. Forcing air into an engine by way of power adders is the widely accepted shortcut to higher performance for late-model 'Stangs. These quick methods are complemented by higher-flowing cylinder heads and exhaust systems. Big fuel pumps and injectors also are incorporated in these systems. CARB typically frowns on such components as they increase the output of hydrocarbons, carbon monoxide, and NOX beyond accepted standards.

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History has shown that CARB-legal products typically fall just a bit short of the 49-state pieces. In a nutshell, while legal bolt-on parts do improve performance over OEM equipment, they still tend to be more restrictive than their non-compliant siblings. As such, its tempting to install 49-state pieces on street-driven Ponies in the Golden State, despite the legal ramifications and vehicle-inspection challenges.

One of the beautiful things about '11-'13 Mustang GTs' vaunted Coyote 5.0 engine is that it makes its impressive, clean power in bone-stock trim. Running clean is the name of the game today, and with a precise PCM calibration, a modified '11-'13 Pony should be just as capable of operating close to CARB's standards. Taking this efficiency into account, engineers at Roush Performance developed a PCM calibration for its '11-'13 Mustang Roushcharger system and submitted it for CARB authorization. Yes, it's the same 2.3-liter Twin Vortices Series kit (PN 421388/Phase 1; $6,099.99) introduced for Coyotes in 2011. However, it's now 100-percent smog legal—a definite boon for 'Stangbangers living in Cali, as well as '11-'13 Mustang owners interested in stepping up to eco-friendly forced induction.

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This is one of those times when we're glad the majority of our tech efforts are conducted in Southern California. It's the most appropriate place for us to install the new Roush blower for a before-and-after smog evaluation. GTR High Performance selected Kurt Schutte's “Stealth 5.0,” an '11 GT for the test. Aside from its clean triple-black interior/exterior layout, Kurt's Pony is stone-bone-stock, and ready for a performance bolt-on that will increase the rear-wheel horses in a hurry.

Ricardo Topete and Eddie Zapata of GTR turned wrenches for this effort, but PCM calibration comes by way of Roush Performance. Yes, that's technically the way it works with the 575hp (crankshaft) Phase 1—and all of Roush's supercharger systems for late-model Mustangs. An overnight shipping package is included with the kit, and a Pony's original ECU is sent to the calibrators at Roush for reflashing.

While highlights of the nuts-and-bolts action are normal for reports like this, it's the dyno and all-important emissions-test results that are critical for this effort. We suggest you follow the information closely, especially if you own a stock '11-up Mustang GT in California—or plan to own one in Cali at some point in the future.

The 2.3-liter Roush supercharger (Roush calls its blowers Roushchargers) is a positive-displacement Eaton TVS featuring two four-lobe rotors that both are twisted 160-degrees. This rotor configuration (as opposed to the three-rotor/60-degree design of other Eatons), along with newly redesigned air inlet and outlet ports, help enhance the supercharger’s volumetric capacity. Greater air volume allows the blower to spin quickly, which creates smooth, efficient airflow for the Coyote engine.

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