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Horse Sense:
Simply put, the fuel-management unit in a supercharger kit raises fuel pressure while under boost, providing the engine with needed extra fuel. When we speak of the step-up ratio of the internal disc-i.e., 12:1-we mean the FMU is boosting fuel pressure by 12 psi for every pound of boost. Likewise, an 8:1 disc will raise pressure by 8 psi/pound of boost.
Among the most common questions we're asked at 5.0&SF is, what's the better power-building option for a street-driven Mustang-a supercharger or a series of naturally aspirated (NA) components? It's a legitimate question, but alas, one that doesn't always have a clear-cut answer. For example, in the world of 4.6 modular motors, supercharging enjoys unrivaled popularity due in part to a limited selection of performance engine parts. Not so in the 5.0 world, where decades of development have resulted in a dizzying variety of traditional speed parts. Add the fact that the small-block Ford V-8 is friendly to the driveway wrench bender, and owners of the little small-block have a difficult, albeit pleasant, choice to make.
So how does one decide between the two alternatives? Better yet, let's ask which you might choose first, 'cause the urge for more is almost guaranteed once you've grown accustomed to either option's newfound grunt. In an attempt to help you develop a reasonable plan, we came up with the idea of sampling both a blower and a naturally aspirated option on one of our resident project cars-yours truly's '93 LX.
Before we rolled onto the...
Before we rolled onto the dyno to establish a baseline, we turned to McCarville Ford for its high-quality and price-friendly tune-up kit. Just $99 buys a set of FRPP 9mm ignition wires in the color of your choice, along with a Motorcraft cap and rotor, a fuel filter, a PCV valve, and spark plugs for a variety of stock and aftermarket cylinder heads. There's no question you're getting quality parts here.
This last-year rendition of the Fox-body Mustang has been the subject of several previous install articles, including a Maximum Motorsports suspension and a Ford Racing Performance Parts Cobra brake kit. You might say we've practiced what we preach here, as remedying the weak links of the '79-'93 models has brought us to the point where we're clearly ready for more power. We've established a budget akin to a midlevel supercharger kit-that is to say, a blower that's set up for modest street applications yet still has room to grow. This time around, we tried on Vortech's whisper-quiet SQ kit, which retails for just over $3,000 and includes important extras such as timing retard and added fuel delivery. The SQ is virtually identical to the highly popular S-Trim setup, with the exception being the V-2 SQ head unit, which utilizes a quieter gear design than Vortech's traditional straight-cut cogs.
We'll install the Vortech after establishing a stock baseline, dyno the results, and remove it in preparation for a naturally aspirated buildup of a similar budget. Of course, choosing NA parts is even more complex than sifting through a myriad of blowers, but in the end, a number of our critical components will wear the Edelbrock badge-in large part because we've been wanting to test the company's Performer 5.0 Package. This combination of Edelbrock's Performer intake, aluminum heads (PN 6037), 70mm throttle body, EGR spacer, headers, and camshaft, is billed to produce 300 flywheel horsepower and will result in a subtest of sorts within our larger combination. Dyno runs will be made after each modification to help determine the worth of each individual bolt-on. Finally, once our comparison of the blower and conventional speed pieces is complete, we'll throw the whole shebang together to see how the blower responds to the engine's enhanced breathing.
A couple of points about our test car bear mentioning. The '93's engine is completely stock, with the only power building/supporting accessories being a 190-lph in-tank fuel pump, a K&N air filter, and an X-pipe in the intermediate exhaust position. In what might seem an unusual move, we're doing all this work on an original engine that just turned 100,000 miles. Huh? Well, considering Ford hasn't built a 5.0 pushrod Mustang for some seven years now, think of the large number of enthusiasts driving around with similar mileage under their hoods. Granted, spending a couple grand on a stout short-block would be the wisest approach to take, but since cash doesn't grow on trees, spending the same dough for an immediate speed fix is a temptation with which many are faced. We're opting for the latter, and hoping to have a fair bit of fun while we accumulate the funds for an upgraded bottom end.
 Craig Blood welded in the...  Craig Blood welded in the bung for a wide-band O2 sensor the moment we showed up for dyno runs with the Vortech. Monitoring the air/fuel ratio on a blown motor is critical, and Craig shoots for 12:1 to 12.5:1 in such boosted applications, although he looks for a leaner 12.8:1 to 13.2:1 ratio for naturally aspirated combinations. |  Key differences between Vortech's...  Key differences between Vortech's SQ S-Trim kits and the basic A-Trim include the MSD Boost Timing Master and T-Rex fuel pump. The BTM can be dialed in to retard 0-3 degrees of ignition timing per pound of boost, up to a maximum of15 degrees. |  Wouldn't you know, our Panhard...  Wouldn't you know, our Panhard bar obstructed the area Vortech intended for the T-Rex pump to be mounted. Custom Auto's Scott Hicks took it all in stride, quickly fabbing up a pump bracket and altering the Vortech fuel line for installation in a slightly different location. What could've been a challenge for us in the driveway is all in a day's work for Scott. |