John Hedenberg
February 1, 2004

Step By Step

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0402mm_01z Ford_Focus_ZX5 Rear_Side_Drag

We went to the pros at Granatelli Motor Sports in Oxnard, California for our replacement meter and went with its 70mm unit, designed for the '00-02 Focus. It is calibrated for the factory 19-lb fuel injectors and can be used with or without the factory air box and filter arrangement. We chose to scrap the stock and restrictive air box for an open-element filter included with the meter.
0402mm_03z Ford_Focus_ZX5 Underhood_Airbox
The stock air box is not designed with optimum airflow in mind and can be extremely restrictive at higher rpm due to a series of baffles in the lower portion of the box, which are there to help quiet the incoming air stream at higher rpm.
The OEM filter is made from paper and lays flat in the top portion of the air box making it inferior to performance.
0402mm_05z Ford_Focus_ZX5 Underhood_Cone_Filter
For the first modification, we slapped on an open element (cone style) air filter to see if the factory 58mm meter could benefit from a better breathing filter. With just a filter swap, we gained 3.2 hp and 3 lbs-ft of torque.
0402mm_06z Ford_Focus_ZX5 Underhood_Connecting_MAF
Next we removed the factory mass airflow sensor. Crazy Horse Industries owner Chris Winter removed the electric plug from the top of the sensor before loosening the clamp on the factory inlet tube.
0402mm_07z Ford_Focus_ZX5 Underhood_Intake_Hose
After loosening the hose clamp on the tube, the mass airflow sensor can be lifted out from its position.

For some time now, we have been hinting to you Focus enthusiasts that our very own Internet project machine, "The Red Hot Chili Pepper," will be receiving a dynamite and extremely necessary turbo kit from Precision Turbo and Engine. We actually have the kit on hand and will be tackling the install next month (October, '03) but for now, we'll take the easy route to performance by upgrading the factory mass airflow sensor with a 70mm unit from Granatelli Motor Sports in Oxnard, California. This simple mod should give us a few extra ponies and will become a welcome addition when the turbo is finally strapped under the hood.

When we first received the Infra-Red 5-door, we blasted it with a host of bolt-on goodies. A Focus Central 65mm throttle body improved our intake flow and a Focus Central equal length, 1 5/8-inch shorty header with a full 2 1/4-inch, mandrel bent stainless steel exhaust system from Magnaflow dramatically improved the exhaust tone.

As for looks, the original rim/tire combo was tossed in favor of a set of trick Konig Blatant Opal dubs, which roll on high performance Nitto NT450 18-inch tires. We also have a 75hp nitrous kit from Nitrous Express residing under the factory hood, which dipped us into the 14-second zone at over 90 mph.

One component we never thought of trying out, however, was a simple mass airflow sensor upgrade. Along with lower (numerically higher) rear end gears and maybe an aftermarket short-throw shifter, a larger mass airflow sensor is usually one of the first items most Mustang owners embark on but we, sadly, never took that into consideration with our Focus.

With the small-in-size 2.0-liter ZETEC engine under the hood, you can bet your bottom dollar that more airflow is what this mill needs and we hope that a larger mass airflow sensor will become beneficial in the quest for more power. The factory mass airflow sensor on the Focus measures in at a minute 58mm while the Granatelli Motor Sports unit is noticeably larger at 70mm. The meter also comes with its very own open element, cone style air filter, improving the overall flow and breathing of the engine and helping to add horsepower.

"We sell a wide range of larger mass airflow sensors for all types of vehicles and offer a 70mm unit for the '00-02 Focus," explained Dennis Sorensen of Granatelli Motor Sports. "The sensor is a duplicate of the unit found on a 4.0L Ford Ranger truck but is calibrated for use on the Focus. It retails for $367 and should add a fair amount of power to a normally aspirated engine combination. With a power adder you may see even more."

In order to find out what type of gain we would see we stormed over to Crazy Horse Industries in South Amboy, New Jersey and began with a generous engine cool down before making a few base runs on the in-ground Dynojet. With the stock air box, filter and meter aboard we mustered a best of horsepower figure of 97.0 and 102 lbs-ft of torque. Not bad but not mind-bending either.

We were down in horsepower slightly from past dyno pulls but the weather was extremely humid, which may have caused a slight fluctuation in our readings. Nevertheless, we had our base numbers but before jumping into the Granatelli meter we tried slapping on an open element air filter to the factory Ford meter.

The stock air box is rather restrictive and not designed with optimum performance and airflow in mind. It has baffles in it designed to keep the incoming air charge entering the intake tube as quiet as possible and the factory air filter is made from low quality paper and not very effective to high air speed. To our surprise the open element air filter raised the bar to 100.2 horsepower and 105 lbs-ft of torque. We are well aware of the benefits of a non-restrictive air filter but were still surprised with the 3.2 hp and were eager to strap on the larger meter to see what might become of it.

After removing the OEM meter we connected the open element air filter to the Granatelli unit and after another lengthy cool down we spun the dyno rollers once again. With the new meter and high performance filter we rounded out the day with 101.3 horsepower and 108.2 lbs-ft of torque at the front wheels. The meter/filter combo was worth a solid 4.3 hp and 6.2 lbs-ft of torque, which is approximately what we were expecting.

Next month we promise to finally install our turbo kit and hope to dip into the high 13-second zone without hitting our 75-hp nitrous kit. We'll then bite our lip before attempting to run both power adders in an attempt to bust into the low 13s. Will our in-house Focus become a low 13-second player or just another on-track casualty? We'll find out next month.