THE STORY OF A 600 HP, STOCK BOTTOM END 7.3L, PART 2

Turbo, Transmission, And Traction Bars

Just to recap, the beginning of this story dates back more than 10 years and it serves as proof that—with the right combination of parts in the mix—a stock bottom end 7.3L Power Stroke can live, indefinitely, at 600 hp. In Part 1, we highlighted the stronger pushrods and valve springs, the heads being re-anchored to the block via ARP head studs, big fuel introduced in the form of Unlimited Diesel Performance 350/200 hybrid injectors and a competition fuel system from Irate Diesel Performance. High-pressure oil needs were met with the late SRP1.1 and Gearhead Sales tied everything together with PCM calibrating, made available by way of a Power Hungry Performance Hydra chip.

By developing an all-in-one T4 turbo mounting kit, Irate Diesel Performance filled a huge void that existed in the 7.3L aftermarket. The company’s system, released more than a decade ago, made it possible to run virtually any T4 BorgWarner or Garrett turbocharger on a 7.3L Power Stroke—which paved the way for all of the 600, 700 and even 800 hp trucks you see today. Irate’s T4 turbo mounting system comes with a new pedestal, exhaust collector with 304 stainless steel up-pipes, 304 stainless intercooler pipes and intake Y, a two-piece downpipe (3-inch on OBS trucks, 4-inch for Super Duty’s), a stainless air intake tube, oil and drain lines (and fittings), and all installation hardware. Kits start at $2,145.

When you convert a 7.3L to Irate’s T4 mounting system, there are literally dozens of turbo options to choose from. In the 7.3L application—and for horsepower goals in the 600hp range—the S467.7 BorgWarner is a popular choice. Opting to do something slightly different, we reached out to Fleece Performance Engineering, a company with a billet S468 that was supporting north of 800 hp in Duramax applications while still offering great drivability. Its T4 S400 sports a billet 68mm (inducer) compressor wheel, makes use of a 81/87mm turbine, and utilizes a relatively tight .90 A/R exhaust housing. Our thinking was that the 87mm turbine would provide solid high rpm exhaust flow and the .90 housing would offer quick spool up despite the large turbine. It works very well.

Because we were campaigning the original engine in our ’97 F-350 and ’94.5-’97 versions didn’t come intercooled, we had to source an intercooler and then get it installed. After scoring a Spearco unit taken out of a 2000 Super Duty for next to nothing, we had it leak and pressure tested at a local radiator shop. Then it was time to tear into the front-end of the OBS Ford.

Depending on your mechanical skill level, installing an intercooler in an OBS Ford can be an extensive undertaking. For one, the radiator core support has to be cut yet not hacked apart. Our lives were made easy thanks to using a plasma cutter. But first we mocked up and measured precisely where the intercooler pipes were going to route around the radiator (measure twice, cut once right?). Our intercooler install also consisted of repurposing some stainless steel bracketry we had at our disposal in order to securely mount it.

But that was only the beginning. The factory turbo—and in fact the entire OEM turbo arrangement—had to be scrapped in pursuit of adequate airflow. We found what we needed in Irate Diesel Performance’s T4 turbo mounting system. The company’s all-inclusive turbo kit facilitated the use of an S400. And because the build involved a ’97 F-350—a truck that left the factory void of an intercooler—installing an intercooler was part of the extensive turbo system upgrades. Then when it came time to both harness the newfound horsepower and torque, we contacted John Wood Automotive for a billet internal E4OD, along with adding a set of high-quality traction bars from One Up Offroad.

Next time, we’ll show you the truck’s dyno sheet, its 8.00-second eighth-mile timeslips, and its odometer—225,000 miles strong, and counting.

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