Michael Johnson Associate Editor
October 1, 2002

Horse Sense:
The mass air meters on our beloved Mustangs tell the EEC processor how much air is coming into the engine. They do so by attempting to hold a wire inside the meter at a constant temperature. As air travels over the wire, it requires more voltage to maintain that temperature. The EEC processor then converts that voltage value into an airflow number. A C&L mass air housing allows the use of larger injectors by changing the size of the sampling tube that surrounds the sensor. Naturally, this changes the airflow over the sensor, thus changing the voltage output of the meter and the airflow the EEC sees.

At some point during your Mustang ownership, you probably swapped out a mass air meter, a throttle body, and a fuel-pressure regulator. Most of us started out by swapping these items on our Fox cars and gaining a fairly nice boost in horsepower.

Well, we wanted to see what might be gained by swapping these items on a Four-Valve modular engine. Specifically, we're using Tony Beake's '96 Cobra convertible to test our horsepower-chasing theory. Tony is the owner of Need For Speed in Clearwater, Florida. The company specializes in mail-order Mustang performance parts, but it also does quite a bit of installation work in-house. For the dyno numbers, we scooted over to Tune Tech Automotive Diagnostics in nearby Tarpon Springs, Florida.

So, why would anyone want to swap out their car's mass air meter, throttle body, and regulator? First, they're a cinch to change. Second, all three are relatively inexpensive (except the throttle body in our case). Third, each part is a proven power producer, albeit in small increments. And, fourth-especially on a modular engine-apart from adding a supercharger, turbo, or nitrous, there's not much else you can do powerwise without getting into the intake and heads.

Swapping out these parts is a good step toward realizing your horsepower goal without swapping out too many Benjamins.

The Tale Of The Rollers
After we arrived at Tune Tech, Tony Beake and Steve Loeffler allowed the car to cool down and then made two back-to-back runs. We used the best of these two, which was 253 hp and 260 lb-ft of torque, as our baseline. The horsepower peaked at 5,750 rpm, while our torque number reached its peak at 4,000 and 4,250 rpm. We let the engine cool down and installed the C&L mass air meter package. This time the car made peaks of 261 hp and 265 lb-ft of torque. Letting the engine cool down once again and installing the throttle body resulted in power numbers coming in at 264 hp and 267 lb-ft of torque. With the adjustable fuel-pressure regulator in place, we were unable to get back to those numbers-mostly because we ran out of time and because we ran it several times back-to-back dialing in the fuel pressure. As such, we ended the day at 263 hp and 265 lb-ft of torque.

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