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Mustang Digital Mass Air Meter - Mass Appeal
Abaco's Dynamic New DBX Simplifies Tuning For Mild Or Wild EFI 'Stangs
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.
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.
Doug Wallace, the man who developed Abaco Performance's new DBX mass-air meters, and our friend (and Abaco dealer) Rick Anderson, disagree with the notion that boosted vehicles need a larger mass air with more airflow metering range, and also feel that calibrating a mass air specifically for injectors is not the proper way to tune a fuel-injected Mustang. The mass-air meter controls fuel injectors. So, if injector flow is the only variable that is addressed with a meter, load scaling in the PCM will undoubtedly be jacked. For a long time, popular belief was that a mass air should be dialed-in through PCM tuning. However, with DBX, the meter's calibrations are the only settings that are changed, using software that is downloaded from the company's Web site, and a database of programs for EEC-IV, EEC-V, and Oak-era (Spanish, Silver, and Black) electronics that have been developed with consideration for an aftermarket air-intake tube of some sort, and any type of injector package you can think of.
"This is a meter that will grow with any application," says Rick. "If you have this meter on your '89 Mustang and then you go and buy a new '09, all you have to do is take the meter off the 5.0 engine and transfer it onto your new car, buy the new harness, plug it in and recalibrate it."
Seems "too easy," doesn't it? Read on through the following photos and captions to learn about our experience with DBX, during your tech editor's late-summer visit to Anderson Ford Motorsport, located deep in the cornfields of Clinton, Illinois.
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"Depending on injector size, a mass air usually operates below 2.5 volts in basic, street-driving conditions. Signals between 2.5 and 5 volts are attributed to wide-open-throttle and really aggressive driving," Rick says. "With today's Mustangs, the PCM's Adaptive Learning doesn't change below 3,000 rpm, but we can change it from 3,000 to WOT using DBX." This is a shot of the DBX software's advanced tuning screen, which is used for reading or modifying base mass air voltage tables (the software contains data for all '89-'09 Mustangs, including Cobras) to suit the needs of your car. Making fuel-trim adjustments-through mass-air voltage alone-with this tool is done in similar fashion to changing audio frequencies with a stereo system's graphic equalizer. The slides below the graph are moved up or down to increase or decrease voltage amounts for a richer or leaner fuel trim. Changes are represented in the "V Out 1" column, which represents the mass air's new voltage output, per number of kilograms-per-hour of airflow.
It's not often that we hit the dyno as hard as we did during our test of the Abaco Performance DBX, and not have our hearts set on making big steam with the Mustang being tested.
But, that's the way it was during our two-day bolt-on/dyno-run marathon, as our focus for this tech effort was to confirm Abaco's claim that a DBX literally could be the stop-all, end-all mass air for any '89-'09 Mustang that has or will receive performance upgrades, and requires tuning that will bring air/fuel ratios into the accepted range for the particular application.
Each 'Stang we tested did show moderate power gains with DBX (Note: The Roush, OEM Mustang GT and OEM Shelby GT500 air intakes also were replaced with Anderson Ford Motorsport Power Pipes, which are considerably larger in diameter and usually yield 15-20 rear-wheel-horsepower gains), but the big deal for this test was the fact that after getting baseline air/fuel data, we were able to manipulate mass-air voltage (with DBX's base calibrations and tuning software) for one meter, install the meter and Power Pipe on completely different cars (supercharged Roush/bone-stock Mustang GT), and for all of the test 'Stangs, dial-in air/fuel ratios that mirrored and/or improved those of the baseline runs for each-all without tuning the PCM!
DBX is easy to use, and all of its support and access to its database can be obtained at no charge, through Abaco's Web site. We won't go so far as to say that the days of sending a mass air off to be calibrated or tuning a hopped-up 5.0 or 4.6 engine with any of the popular software are over, but, based on our experience with Abaco Performance's slick, new meter, old-school EFI tuners may want to think about changing their ways.
As we mentioned earlier in this report, while Abaco Performance's DBX really is applicable to pretty much any late-model Mustang that uses a mass-air sensor, the unit really thrives when it is used to support blow-through turbocharger or supercharger combinations that oftentimes are difficult to tune at lower rpm.
Zach Sarver's '06 GT was one such vehicle. Although upgraded with a stout long block, and power-adder hardware that should have easily put Zach's Pony in the 550 rear-wheel-horsepower zone (HP Performance blow-through 70mm single-turbo system), achieving even 400 horses was a struggle for Anderson Ford's dyno tech Danny Biggs, as the stock meter's limited voltage range caused consistent lean spikes at approximately 4,000 rpm, which forced Danny to prematurely abort every baseline run. "He (Zach) asked me what would I do (to correct the situation) if it was my car?" says Rick Anderson. "I told him that if it was my car, I would cut the inlet tube and install a DBX."
So, while the 'Stang was still strapped on the dyno, Danny reconfigured the turbo system's induction setup to incorporate an 85mm DBX, and proceeded to make another go at tuning. Positive results were instant. With only the base calibration loaded in the DBX, improvements were seen across the board (rpm, horsepower, torque and air/fuel).
Danny then made a copy of the base tune, upon which he made changes to mass-air voltage settings and stored each version of the new calibrations directly in the meter (DBX units are capable of holding 10 different tunes), and in a matter of roughly 40 minutes, Danny steadily improved the Mustang's low-end, and wide-open-throttle performance by simply adding the DBX mass-air to Zach's setup.