With the H&S Black Maxx tuner set on the hottest position, the factory ball-bearing Garrett turbo now makes 32 psi of boost on the street. On the rollers at Randall’s Performance & Accessory, we were only able to squeak 30 psi out of the truck on its SuperFlow load-cell dyno. With the H&S Black Maxx tuner set on the hottest position, the factory ball-bearing Garret The time has come to get more aggressive with our ’11 Super Duty’s performance. So far, we’ve added power to the 6.7L Power Stroke while retaining the diesel particulate filter (DPF), selective catalytic reduction (SCR), and exhaust gas recirculation (EGR) systems. Now, we’re removing all three in order to pave the way for more performance. After getting our hands on one of H&S Performance’s Black Maxx tuners over the winter, we conducted some street and dyno testing. With a freer-flowing exhaust thrown into the mix, an uncorrupted intake tract, and more rear wheel horsepower, we’re formulating our next power-adding attack. Stay tuned, because in the following months the horsepower level will only be climbing. On the dyno, the Super Duty laid down 875 lb-ft at just 1,900 rpm, and torque didn’t fall below 800 lb-ft at the wheels until 2,700 rpm (which explains why the truck pulls so hard on the street). Our horsepower curve shows a different story, however. Notice the dip in our power curve at 2,800 rpm? This is because rail pressure dropped from 29,000 psi to 22,800 psi and recovered once the truck pulled through the load the dyno had placed on it. According to H&S, the drop in rail pressure we saw may not occur on every truck. In addition, H&S has stated that some tuning changes should prevent this problem from occurring on any trucks in the future. *All results are shown using the Society of Automotive Engineer’s (SAE) correction factor. All dyno pulls were made in Fifth gear, and with traction control off. All tests started at 52 mph and ended at 95 mph. A EGT Probe B Catalytic Converter C DEF Doser Valve D DPF E pressure Sensor Since the H&S tuning can disable the SCR and DPF regeneration process, we removed the factory exhaust system—all 140 pounds of it. As you can see here, we’ve labeled all the key components in the OE system: four EGT sensors, a diesel exhaust fluid (DEF) doser valve, and an oxygen sensor after the diesel particulate filter. A EGT Probe B Catalytic Converter C DEF Doser Valve D DPF E pressure Sensor Since the H&S We replaced the factory exhaust system with this 4-inch, downpipe-back system from Street Diesel Performance. The kit bolted right up to the 4-inch factory downpipe, and this particular system retained the factory tailpipe. We replaced the factory exhaust system with this 4-inch, downpipe-back system from Street The Black Maxx allows you to select your power level on the fly and monitors all engine vitals such as boost, exhaust gas temperature, engine speed, throttle position, coolant temperature, and more. The Black Maxx is available with both the DPF and DPF-delete tuning and retails for roughly $1,200. The Black Maxx allows you to select your power level on the fly and monitors all engine vi Our 6.7L is breathing even easier (and cleaner) now, thanks to H&S Performance’s $149 EGR delete kit. The kit comes with block-off plates that allowed us to remove the dual EGR coolers, the coolant lines running to the cooler, and the manifold up-pipes. We also installed a pyrometer in the manifold up-pipe block-off plate for accurate exhaust gas temperature readings. Our 6.7L is breathing even easier (and cleaner) now, thanks to H&S Performance’s $149 EGR The dual EGR cooler on Ford’s 6.7L Power Stroke is massive. Stripping it off the engine not only exposed the passenger-side valve cover, it also took 25 pounds off the truck’s curb weight. The dual EGR cooler on Ford’s 6.7L Power Stroke is massive. Stripping it off the engine no With summer coming, we decided to upgrade the Super Duty’s looks a little as well. When our ’11 isn’t on the dyno or at the dragstrip, it will be sitting on these 22x11-inch Fuel Hostage wheels from MHT Luxury Alloys. A set of 325/55R22 Nitto Trail Grapplers give the F-350 a tough, go-anywhere look. With summer coming, we decided to upgrade the Super Duty’s looks a little as well. When ou SOURCES Nitto Tire 6021 Katella Avenue Suite 250 Cypress CA 90630 877-565-8448 www.nittotire.com Randall's Performance and Accessory RR 1 Box 134 Gladstone IL 61437 309-627-2500 www.randallsperf.com H&S Performance 4012 S. River Road St. George UT 84790 888-628-1730 www.hsperformance.com Stree Diesel Performance 860-250-6082 MHT Luxury Wheels 12300 Industry Street Garden Grove CA 92841 800-493-7891 www.mhtwheels.com By Mike McGlothlin Enjoyed this Post? Subscribe to our RSS Feed, or use your favorite social media to recommend us to friends and colleagues!