Boost Works pioneers the first Kenne Bell Twin Screw-blown S550 with impressive results
By Steve Turner
Photos courtesy of Boost Works
It’s truly amazing how quickly the performance arms race has escalated with each new generation of the Mustang. While the factory continues creating better, yet more complex vehicles for a wide array of customers, there is an audience that demands a much higher level of performance. Thankfully there is a rabid aftermarket to support those desires, and one upstart company—Boost Works of Katy, Texas—stepped up to create the first Kenne Bell-supercharged 2015 Mustang GT a scant three weeks after receiving this car.
Of course being a pioneer means overcoming some obstacles. The Boost Works crew—Travis Burelle, Curt Howell, and Jason Haynes—was in a hurry so they started with the Kenne Bell supercharger designed for the S197 Coyote. This meant they had to tweak a couple things to make it fit, but rest assured a direct-fit Kenne Bell S550 system is on the way. For now, however, Boost Works developed an install kit for the earlier system. It incorporates engine mounts, a machined lower plenum, a 4.5-inch inlet pipe, a heat exchanger with brackets, hoses, an intercooler pump, and machined subframe spacers.
“We knew going into this project that fitment would be a challenge. Kenne Bell was willing to work with us on a prototype, and parts were sent over. The 3.6LC supercharger is a little over 1 inch taller than its 2.8L counterpart. Preliminary measurements indicated that we had a little less room to work with in regard to hood clearance, as the nose of the S550 is a tad shorter than the S197. Firewall clearance was also a concern, but turned out to be less of an issue,” Travis Burelle of Boost Works explained. “It looks as though the 4.2- and 4.7-liter head units will fit with some light massaging. To address the issue, we machined spacers to go between the frame and front subframe. We also machined a set of engine lowering mounts. This allowed us to (just barely) cram this monster under the hood.”
They supported the blower install by upgrading the clutch with one of McLeod Racing’s robust RST twin-disc setups, and opened up the exhaust with some cat-delete pipes. They also added some Delrin bushings to the independent rear. Of course, the most important aspect of the upgrade was getting the PCM to play along with the new supercharger.
“Tuning has proven to be challenging, for many reasons. The car was finished and ready to go two weeks prior to us actually tuning it. We were anxiously waiting for updates from HP Tuners and SCT Performance in order to get the tools needed to tune the car. In the end, it ended up being a combination of both. We used SCT’s logging software to datalog, and HP Tuners software to recalibrate the PCM. Both are still in their infancy, and both are missing parameters, which made the job much tougher,” Travis elaborated. “Ford changed up a few things with the strategy, and there are double the amount of tables in some areas. Luckily, we employ a very skilled calibrator. Armed with a pair of laptops, Jason Haynes (of The Tuning School) went to work on the stubborn S550. After a few long nights (and boxes of cold pizza), we were able to get the car dialed in. Back-to-back 655- and 653-rwhp dyno pulls told us that we were done for now. This was at 11.93psi max boost, at 17 degrees of timing, and a very safe 11:1 A/F ratio.”
You can see the Boost Works Mustang hitting the dyno for tuning and full validation pulls in these videos:
Once the car was tuned, Travis and company had the chance to drive the first Kenne Bell-supercharged S550. As you might expect, the combination was a lot of fun. You can check out some of their South of the Border antics here:
“We love the refinement that the S550 chassis has brought to the table. You can certainly tell that Ford spent a lot of time making sure that the fit and finish was up to par for a globally marketed vehicle. The emphasis on NVH is apparent and the IRS makes the car seem much more sure-footed than the outgoing S197. Doubling the power output has turned this car into a monster, and for the first time in a long time, I think it’s something that I could drive daily without any complaints,” Travis enthused. “The added grunt from the big Twin Screw results in a huge grins, and shredded tires. Nothing is lost in the handling, and the IRS (with its 35-spline axles) seems to be handling the abuse without any fuss. We’ve been big turbo advocates over the years, but these big Twin Screw superchargers have really made us rethink things. As it turns out, you can have your cake and eat it too!”
They also did a few test launches to see how the bushing upgrades to the IRS worked out with the sticky tires, as the next stop for the Boost Works Kenne Bell-boosted S550 is the drag strip.
“When Ford announced that the S550 would lose the solid axle in favor of IRS, everyone was concerned (including us). After looking things over, ordering factory parts for inspection, and finally putting over 650 rwhp through one on sticky tires, we can say that Ford did their homework on this one,” Travis said. “From 35-spline axles, to offset diameter halfshafts (to combat harmonics issues), heat treatment, and beefy CV joints, it didn’t take much on our end to shore up the IRS. We machined a set of differential mount bushings out of Delrin and that’s about it. The car has zero wheel hop on Nitto 555Rs. Even our Hoosier 28×10-inch slicks failed to upset things. We’re very pleased thus far.”
Naturally, they will keep pushing this combo for increased performance. Another part of the plan for the car is to hit the Texas Mile for some top-speed runs to see just how fast a supercharged 2015 Mustang can run.