Justin Fivella
April 6, 2013

Boost Mode
Last but not least was a Vortech V-3 Si self-lubricated supercharger kit. This giant snail is capable of 1,150 cfm, 22 psi, and 750 hp. The high-output kit comes pullied for 10 psi and is packed with everything needed to build boost, like a fuel management unit (FMU) and T-Rex external fuel pump.

The installation was easy, save for the tall valve covers that necessitated Rankin Performance fabricate a new throttle linkage. This also meant the supplied intake connectors didn't work, so silicone 90-degree elbows from Turbo Hoses and a little more fab work from Rankin Performance had us sitting pretty.

Since we opted for 42-lb/hr injectors the supplied Vortech FMU was deemed unnecessary, but those running smaller sprayers should stick with it. Instead, the BBK adjustable fuel-pressure regulator (FPR) was boost referenced at a 1:1 ratio, so we kicked up the base pressure and let the FPR take care of the rest.

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Dyno Approved
We paid a visit to BRG Racing in Pacheco, California for dyno time and tune tweaking from KC Cager and Chris Doig.

In stock form, our 272,000-mile SSP stick coupe laid down 226 hp and 270 lb-ft to the tires on its Mustang dyno. Torque production was stout, but the show was over above 4,500 rpm—it was out of breath.

The combo performed admirably as it churned out 313 hp and 340 lb-ft for total gains of 87 hp and 70 lb-ft over the baseline. The boost motor made huge torque from 3,300 rpm to redline where it never dipped below 300 lb-ft. A proper NA motor would have a bigger cam and more compression, but our low-comp boost motor still had a pancake-flat torque curve from 4,500 rpm to redline.

Finally, the moment we'd been waiting for, the boosted pulls. Armed with nothing more than a timing light, the MSD BTM, and the BBK FPR, Chris Doig of BRG Racing tweaked our little boost coupe to the tune of 422 hp and 419 lbft at the tires on 91-octane pump gas with 10 degress of base timing. The gains over the NA 347 combo were 109 hp and 79 lb-ft with total gains over the baseline ringing in at 196 hp and 148 lb-ft. The AFR was a fat 10.8:1, but without being able to read the timing properly, it was a safe bet for our track outing the very next day.

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Track Tested
Equipped with worn Lakewood shocks, Eibach Drag springs, 3.73 gears, stock axles, a weathered differential, and a crusty T5 that prevented hard launches and powershifting, our baseline run produced a best of 13.79 at 101 mph. There was little drama, as we simply ousted the clutch, matted the gas, and shifted at 5,500 rpm.

With the boost-friendly motor running in naturally aspirated form, we again hit the track and came away with a best of 12.71 at 109 mph for a total drop of 1 second and 8 mph.

We returned to Sacramento Raceway for the third time with the Vortech V-3 Si strapped on and ready for boost. With the worn-out T5 and stock axles ready to blow, we avoided hard launches and power shifting. Instead, we rolled off the line and put it to the wood. As for the shifts, we lifted for fear of scattering the T5's guts all over the track.

The result? A slow first eighth followed by a big backend surge. In just 11.99 seconds at 121 mph, the boards flashed and the little coupe was crossing the stripe. Boost rolls in around 3,000 rpm and by 4,000 rpm it's getting serious. In fact, the worn-out differential had the one tire spinning on the 2-3 shift even with the ET radials aired down.

Truthfully, there was a lot more left in the combo with a prepped drivetrain and a better tune. What initially felt like a complete project was unknowingly just getting started.

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