Steve Baur
Former Editor, Modified Mustangs & Fords
November 1, 2009
Installation of the Tru-X requires cutting of the factory H-pipe, but keeps the stock catalytic converters intact.

Induction Junction
If the exhaust system is where people make their first changes, then the second place must be the cold-air kit. For this part, Summit Racing sent us BBK Performance's Power-Plus Cold-Air Induction System (PN BBK-1736), which retails for $289.99. From the cast aluminum induction elbow to the high-flow conical air filter, the BBK piece is quite nice, and very wallet-friendly too. Installation was a snap, and the car was up and running.

As the GT turned the dyno rollers, we realized that the air/fuel ratio was much leaner than stock-a testament to the increased airflow provided by the cold-air kit. It was lean enough, in fact, that Gonyon made the call to flash the computer and add a safe amount of fuel to compensate for the added air. While we had a hand-held tuner that fit our budget theme and that we intended to make such adjustments with, it wouldn't work properly and we later discovered that the item was discontinued. Summit Racing supplied us with a replacement, but we had to test that at a later date.

BBK Performance's cold-air kit for the '05-'09 Mustangs is a very popular bolt-on, and its performance showed why.

To remedy the situation while we were on the dyno, Gonyon employed HP Tuners software to reflash the Spanish Oak processor computer and add the necessary fuel to compensate for the increased airflow of the BBK cold-air kit. It's a basic tune-up that is very similar to what many hand-held tuners supply, and it worked great. Power output jumped to 270.54 hp and torque increased to 286.28 lb-ft. That's a gain of 15.6 hp and 25.4 lb-ft of torque.

Pulley Your Weight
Underdrive pulleys worked quite well on the early 5.0L Mustangs, and they've been proven to add a few ponies to the later Mustangs as well. Roush Performance's Underdrive Pulley System (PN RSP-401433) from Summit Racing proved to be a great performer, especially given its meager $220.95 price tag. Though not required, removing the electric fan does simplify the installation of the pulleys by allowing much needed access for tools and hands.

With the installation of the pulleys complete, it was back on the Dynojet rollers where we saw the '06 GT's power and torque increase yet again. Horsepower moved up yet again by 6 hp to 276.57 and torque readily improved by nearly 8 lb-ft to 294.02.

Underdrive pulleys seem to work on just about every Mustang, and ours was no exception. This package from Roush saves weight and increased power too.

Throttle Up
BBK's Power-Plus throttle body (PN BBK-1763) was next on our list of budget-friendly modifications and comes in easily under budget at $299.99 through Summit Racing. The BBK throttle body for our '06 Mustang features twin 62mm bores for more airflow, and the bodies are cast from high-quality 356 aluminum alloy, and then machined on state-of-the-art CNC machining centers to ensure a perfect fit. Other features include double-sealed bearings, O-ringed throttle shafts, and precision die-stamped linkages

When installing any aftermarket throttle body that uses Ford's drive-by-wire setup, it's important to follow the installation instructions to make sure you preload the clockspring in the throttle control unit. The clockspring works as a throttle return spring and if it's not reinstalled correctly, the car may not run correctly and your check engine light may begin to log some trouble codes.

That being said, the Hurricane Performance crew had our BBK piece installed in no time and throttle operation was flawless. The 4.6L Three-Valve apparently liked the extra airflow, as power rose once more from 276.57 hp to 283.50 hp, and torque improved as well, building up from 294.02 to a stout 300.63 lb-ft of twist.