Rick Anderson calibrates Abaco...
Rick Anderson calibrates Abaco Performance's new, "97B," DBX mass-air sensor on our '08 Shelby GT500 test 'Stang. Tuning a DBX requires only a USB-equipped laptop PC, and the company's free tuning software (available through its Web site). This new, digital MAF technology allows tuners (using rpm and air/fuel data from a dyno and wideband O2 sensor) to design precise, mass-air-voltage maps for any EFI engine and power-adder combination, regardless of fuel-injector size, horsepower, and other variables that usually are that are precise downloaded directly into the DBX via USB.
Horse Sense: At last count (which was more than a year ago), the Dynojet chassis dyno at Anderson Ford Motorsport had a confirmed 16,700 pulls on it, since the unit was installed in 1995. "All we've had to do was change the brakes and keep it properly greased," says Anderson's dyno master, Rick Anderson. You better believe we did our part in adding to the "pull count" with this project, as we had three different 'Stangs spinning the rollers in the two days we were there.
Most of our projects or product tests usually are done with a specific target audience in mind. Sure, when you consider this targeting from a global perspective, we're all 'Stangbangers, which would lead one to think that a detailed, granular approach should not be necessary. The reality is, however, many of the parts or principles that we cover-with the exception of wheels/tires, or a product-guide of some sort, and even that can sometimes be a stretch-usually are specific to only one late-model-Mustang style (Shelby GT500, S197, New Edge and Fox) at a time, simply due to the fact that there has never really been an enormous amount of high-performance-parts "crossover" between the platforms. The products that aftermarket manufacturers build for one 'Stang, are not always applicable to another.
We admit, to an extent, we have somewhat settled on this weird from of selectivity as being the accepted "norm" for the last 30 years. So, you can imagine how intrigued we were when we heard rumblings about a new, digital mass air meter that can be swapped between any mass-air-equipped, EFI Mustangs (from Fox to S197), regardless of their engine/power-adder composition.
Attaining an optimal air/fuel ratio has become the most-critical task that must be performed after making high-performance upgrades on fuel-injected 'Stang engines. The job is usually accomplished with the help of a chassis dyno (and wideband O2 sensor to monitor air/fuel) and aftermarket tuning software that enables a tuner to make whatever fuel or timing changes that are necessary for making an engine run smoothly and make a much steam as its components will allow, without blowing up or completely melting down.
OEM-style meters use a slot-style...
OEM-style meters use a slot-style sensor to read airflow. The DBX's housing is made of extrusion aluminum (for durability) and holds two criss-crossing blades that are referred to as, "front" and "rear." The sensor on the rear blade filters a lot of the reversion that normally causes mass-air sensors to freak out. Thanks to this filtration, the front sensor is able to understand the true intake-air charge. For problematic applications, such as controlling massive airflow from big superchargers or turbos in blow-through configuration (more than 15 psi of boost), tuners can use Abaco's "advanced" functions in its software to adjust dampening and the noise threshold for the rear sensor. The highest and lowest noise signals are averaged, and then smoothed out through dampening. Abaco offers DBX in three sizes: 85mm, 97mm and a bell-ringed unit called 97B, which flows an additional 200cfm over the standard standard 97mm unit.
As we've detailed in previous tech reports, high-lift/long-duration camshafts, ported cylinder heads, free-flowing manifolds and power adders, make up the majority of bolt-ons being installed on the fuel-injected engines that power most '87 to present 'Stangs. However, in addition to those components, it's fuel injectors of sufficient size and properly calibrated mass-air meters that are really at the center of achieving total success (improving horsepower/torque without sacrificing drivability) with the hop-up parts we install. Missing the mark in this area not only leads to a Pony's bullet being unable to make the power you expect it to, it also pretty much guarantees the engine will be prone to such nuisances as surging, chugging and misfiring, your 'Stang won't be much fun to drive at all.
Over the last three years we've learned firsthand, the importance of having both the right injectors (our switch from 60 lb/hr injectors to 150 lb/hr squirters took our project '86 T-top coupe's blown 350 from 762 ponies and 100-percent duty cycle at 5,500 rpm, to 830 horses at the feet, without coming anywhere near maximum duty cycle), as well as using the right-size mass-air meter for dialing-in a big-horsepower, blow-through-supercharged (mass air positioned after the blower) modular engine (tuning for street driveability proved to be futile with a Lightning-style meter on our '02 GT's ProCharger-boosted, Two-Valve, until we completely reconfigured the inlet system to draw-through, and added a mondo, 110mm MAF/Ford GT sensor combination that is capable of handling more air).
We've seen plenty of Internet discussions (and misconceptions) about mass-air meters and the "calibration" that many enthusiasts believe mass air meters require when fuel-injector upgrades are made. By calibrating a mass-air, the idea is to achieve Zenlike harmony between the meter, the fuel-injectors' advertised flow rate and a 'Stang's processor. With all factors working together, the mass air is able to generate an accurate voltage signal (per the air mass entering the engine) across the engine's rpm range. Missing on that calibration can cause a meter's voltage to max out before airflow does. This annoyance is called "pegging" the meter (at 5 volts), and when it happens, the processor thinks that airflow has ceased, and in turn the powertrain control module stops adding fuel, causing a lean air/fuel ratio that usually causes power suffers greatly, and the engine-damage monster to rear its ugly head-especially with a force-induced application. As we learned with our Two-Valve project 'Stang, when a mass-air sensor is set up in a blow-through induction system, the range is often reduced because of the smaller intercooler pipe size compared to the original mass-air sensor housing.