After we discovered Sean Porter of ATS Diesel had spent an inordinate amount of time and money on a '99 Ford F-350 called Great White, we were eager to see what he was up to these days. For the second part of his tale, the big fish is similar, but this time it's an '08 F-350 with a twin turbo 6.4L Power Stroke under the hood. We met up with Sean just before the annual ATS Diesels on the Mountain event (featured in our March '09 issue) to see how the new project was progressing.
Obviously, the new 6.4L engine is way more complicated than his 7.3L, but it's cleaner and quieter. And, instead of a single turbo that Ford used on previous Power Strokes, the main component of this system is a smaller, fixed-vane turbo providing constant boost to a bigger variable geometry turbo. The twin-turbo system is designed to provide better throttle response while in motion, but ATS has gone even further with its aftermarket upgrades for the 6.4L.
As on the previous Great White, Sean raided the ATS parts bin for an Aurora 5000 turbo and E-Power programmer. It's critical to have the two working together, since simply pressurizing the cylinders with more boost doesn't do any good without precise fuel and airflow. That's where the E-Power programmer comes in, which requires new software for the newer engine, with fuel maps for as many as 10 different settings. Sean is still playing around with five of them in particular, which increase the power gradually from 60 hp to 120 hp, along with competition and fuel economy settings.
Getting back to the hard parts, the stock high-pressure turbo remained stock for low-end acceleration, but the ATS Aurora 5000 fixed-vane turbo replaced the larger factory unit for even bigger gulps of air. If you look closely at the underhood photos, the engine bay looks fairly stock, except for the AFE intake and some extra sensor lines. That's because he outfitted the factory turbo housing with Aurora's compressor and turbine wheels. Before fitting them inside, he had to machine and chamfer the entire housing diameter about 40 to 60 thousandths, leaving about two thousandths of clearance between the blades and wall.
In contrast to the generic factory unit, the ATS fixed blades on the billet wheels are custom shaped for better efficiency and a bit more pitch. The initial flow of exhaust gas from the manifold has not been changed. Although, since the downpipe is still the stock 4-inch diameter, it connects to a 5-inch exhaust system via an adaptor.
For engineering purposes, Sean mounted six blue-tinted instruments above the rearview mirror. There is a gauge for each turbo to monitor drive pressure, along with a monitor for exhaust backpressure, boost pressure, and exhaust gas temperature. He's being extra careful on the power gains to avoid mistakes made in the past. Why so? The reason is fairly obvious: "It's called money. My theory is I'm gonna drive one of these trucks home in one piece. The new emissions equipment makes it much more of a challenge as well."
A slew of Auto Meter gauges surround the rearview mirror, where EGTs, boost from both turb
Aside from an AFE intake, the engine compartment looks relatively stock. But the low-press
The Gorilla exhaust stacks from ATS route out behind the cab after flowing through one of
Speaking of emissions, the only other mods on the engine itself are ATS Gorilla exhaust stacks with a high-flow diesel particulate filter. Both of those exhaust products are new for ATS, and the latter one is now in final testing. As of this writing, it's said to improve exhaust flow by 30 percent, and doesn't force the truck into regen as often.
It is obvious that diesels are getting more powerful from the factory. On his 6.4L, Sean is already creeping toward the 500hp mark with 1,100 lb-ft of torque. Making the most of the power gains are several ATS upgrades for the drivetrain, including a full-billet 5R110 transmission, a deep pan, Co-Pilot transmission controller, and a Five Star torque converter. The front and rear gear ratios are substantially lower as well-4.56 gears as opposed to 3.73 from the factory.
To take the project to even greater heights, Sean raised the suspension eight inches with a Fabtech lift kit, along with traction bars and a steering stabilizer. But that came with a downside. "The funny thing is that after I lifted the truck, I went to our first NSPA sled pull event and broke the rear pinion, which dropped down into the ring gear and tore it up. I also broke the left front axle hub. This was certainly a testament to the torque and horsepower the new '08 combination was making. That day my first Great White towed the '08 home." Hardly an auspicious start, but it's a good thing he had a backup rig.
After that, Sean took the suspension apart and cryo'd the front and rear axles as well as the pinon and ring gears. Then to add some flash, he painted his suspension ATS purple, and threw on an ATS rear differential cover, along with a set of 20x12 Revolver rims from Rev Wheels. He also painted the fender flares to match the two-tone scheme of the truck.
With all that done, what does the future hold for Sean's Great White Fords? Well, on the older 7.3L Power Stroke, Sean would like to build a common-rail system utilizing Duramax injectors. As for the 6.4L, he wants to make sure the research and development on the high-flow DPF is all sorted out before messing with the injector setup. Once he dives into the internals, he's thinking of developing head studs but won't reveal any detailed plot points until he's opened up the engine and seen what's inside. So stay tuned for Great White, Part III. DP
A set of 38x15.50 Dick Cepek Mud Countrys were mounted on 20x12 Revolver wheels to complem
Sean monitors every aspect of the twin-turbo 6.4L. Here you can see a probe coming off the
Despite being lifted and riding on 38-inch tires, Sean told us that with the engine, and e
Both the front and rear axles were outfitted with ARB Air Lockers, and these switches on t
Here you can see the dual-shock-with-reservoir suspension Sean went with, as well as the s
After breaking the rear pinion, Sean disassembled the front and rear axles and cryo'd them