Photo 1/10 | 500hp Power Stroke Part 4 1997 Ford F 350 On Dyno | 500hp Ford Power Stroke Part 4
Photo 2/10 | 500hp Power Stroke Part 4 1997 Ford F 350 On Dyno | 500hp Ford Power Stroke Part 4
Photo 3/10 | 500hp Power Stroke Part 4 ts Performance Six Position Chip | Taking advantage of Gearhead Automotive’s lifetime free reburn policy, we sent in our TS Performance six-position chip for a different tuning arrangement—one that called for a new performance setting capable of getting us to 500 hp. We also retained our previous performance setting (good for 436 rwhp, Aug. ’11) as a position on the chip so we could see—all else being equal—what the higher-flowing turbo system and intercooler gained us.
Photo 4/10 | 500hp Power Stroke Part 4 borgwarner S300sx3 Turbo | Armed with the 7.3L engine’s flow data, some sophomore compressor map knowledge, and BorgWarner’s catalog, we sat down, crunched the numbers, and decided on a turbo. Knowing peak horsepower would be made at roughly 3,000 rpm and that we’d probably see 40 pounds of boost, Fleece Performance’s Billet 66/73 version of BorgWarner’s S300SX3 caught our eye. It offered the widest compressor map available for our application: At peak boost, we’d be out of the overspeed zone, and at low rpm and low boost, we’d avoid the surge line. This is ideal when sizing a turbo for daily driven, street use. The S366 charger features a billet-aluminum, 66mm compressor wheel (inducer), a 73mm turbine wheel (exducer), and a 0.91 A/R non-wastegated turbine housing.
Photo 5/10 | 500hp Power Stroke Part 4 pro Comp Boost Gauge | In order to keep an eye on the turbo’s drive pressure while on the dyno, we picked up this 100-psi mechanical boost gauge from Auto Meter. We also opted to run its 1⁄8-inch NPT (male and female) pressure snubber to keep the pointer movement on the gauge from fluttering. In a perfect world, seeing a 1:1 ratio of drive pressure to boost pressure is ideal, but street-sized turbos can live just fine at 1.5:1.
Photo 6/10 | 500hp Power Stroke Part 4 exhaust Backpressure Sensor Port | Not wanting to drill an extra hole in the exhaust manifold (only to plug it later), the guys at Randall’s had the perfect solution. They recommended we utilize the exhaust backpressure sensor line behind the high-pressure oil reservoir. With the snubber installed first (arrow), followed by coiled 1⁄8-inch copper line (to dissipate exhaust gas heat), an adapter, and plastic 1⁄8-inch line, we snaked the gauge into the cab of the truck.
Photo 7/10 | 500hp Power Stroke Part 4 fuel Pressure Regulator | With new, more aggressive PCM tuning, we were skeptical of our electric Super Duty lift pump’s ability to maintain 65 psi of fuel supply pressure at wide-open throttle. To know for sure, we hooked a 100-psi, mechanical fuel pressure gauge up to the regulator. We then taped the gauge to the windshield so we could monitor fuel pressure from inside the truck.
Photo 8/10 | 500hp Power Stroke Part 4 walbro Lift Pump Installed | After our first full-power attempt to hit 500 hp fell short (493 hp), we found ourselves glad we’d brought the Walbro unit and installed it. The only thing required to make it work with the rest of our CPR electric fuel system was a different inlet fitting: one with male 1⁄8-inch NPT on one end, and a 3⁄8-inch barb on the other.
Photo 9/10 | 500hp Power Stroke Part 4 overboost Annihilator | Surprisingly, we had to add a mechanical boost fooler to our list of upgrades. On our first few dyno pulls, the truck bucked around 2,600 rpm when under load. With Ford’s IDS (integrated diagnostic system) hooked up via the OBDII port, we were able to log a run. There, we noticed the frequency-based MAP signal began to oscillate once actual boost started to take off (readings varied from 7 psi to 45 psi). This Overboost Annihilator from Strictly Diesel (shown) is a common add-on for Super Duty 7.3L owners (’99 to ’03), in which defueling typically takes place once the MAP sensor (which is voltage-based) sees roughly 24 psi of boost. On ’94 1/2 to ’97 models, it seems to be the MAP sensor itself that causes the problem (not the PCM). Essentially a regulator that intercepts the MAP line, Strictly Diesel’s boost fooler only allows the PCM to see a maximum of 22 psi.
Photo 10/10 | 500hp Power Stroke Part 4 walbro Lift Pump | Planning ahead, we brought this Walbro GSL392 aftermarket lift pump with us. The high-pressure inline pump is popular with the 7.3L community for its affordability, reliability, and simplicity. It’s a direct bolt-in replacement for a factory ’99 to ’03 pump and can easily support 500hp applications.