500hp Ford Power Stroke Part 4

500Hp Power Stroke Part 4 1997 Ford F 350 On Dyno

The term “dyno-proven” has a nice ring to it, doesn’t it? Dyno testing has a way of determining whether or not certain combinations of parts work, and it allows you to simulate how a truck will perform on the street. For the finale of this series, it was time to face the music with our ’97 F-350, so we strapped it to the rollers at Randall’s Performance. If you recall, we upgraded our 7.3L’s pushrods and valvesprings in preparation for handling more horsepower (May ’12), as well as added the supporting modifications needed to get us there: a new turbo mounting system, turbo, and bigger intercooler (Sept. ’12).

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.

Taking advantage of Gearhead Automotive’s lifetime free reburn policy, we sent in our TS P

In addition to measuring the truck’s horsepower, we kept an eye on a host of other items vital to overall performance. We monitored the new turbo’s drive pressure-to-boost ratio, made sure our high-pressure oil system was still holding strong, and we even pitted a stock Super Duty lift pump against an aftermarket pump. We also discovered that some modified ’94½ to ’97 7.3L engines might, in fact, need boost foolers. Once the wheels stopped turning, the dyno told us the turbo and intercooler upgrades alone (without any PCM tuning changes) provided significant gains. Read on to see how we cracked the 500hp barrier with our 7.3L Power Stroke.

Parts List
Total $247.34

Part:	Vendor:	Details	Price:
Walbro lift pump	Summit Racing	Upgraded (universal) electric lift pump capable of flowing 255 lph, PN GSL392	$112.95
Overboost Annihilator	Strictly Diesel	Boost fooler prevents finicky ’94½ to ’97 MAP sensor from seeing excessive low-rpm boost	$59.95
Drive pressure gauge	Auto Meter	100-psi boost gauge to monitor drive pressure-to-boost ratio, PN 4306	$56.95 (Summit Racing)
Snubber	Auto Meter	Reduces pressure spikes resulting in gauge fluctuation, PN 3279	$17.49 (Summit Racing)

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.
Armed with the 7.3L engine’s flow data, some sophomore compressor map knowledge, and BorgW
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.
In order to keep an eye on the turbo’s drive pressure while on the dyno, we picked up this
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.
Not wanting to drill an extra hole in the exhaust manifold (only to plug it later), the gu

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.
With new, more aggressive PCM tuning, we were skeptical of our electric Super Duty lift pu
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.
After our first full-power attempt to hit 500 hp fell short (493 hp), we found ourselves g
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.
Surprisingly, we had to add a mechanical boost fooler to our list of upgrades. On our firs

500hp 7.3L Recipe
Although we’ve added many parts to our ’97 F-350 over the years, this is the list of modifications we used to break the 500hp mark.

John Wood Automotive Street Performance E4OD transmission
Unlimited Diesel Performance 238/80 hybrid injectors
DieselSite Adrenaline high-pressure oil pump
DieselSite CPR electric fuel system
Walbro lift pump
Irate Diesel Performance T4 turbo system
Fleece Performance S366 turbo
Spearco intercooler
ARP head studs
Comp Cams 910-16 valvesprings
Hamilton Cams pushrods
Gearhead Automotive Performance chip
MBRP 4-inch exhaust
K&N air intake
Total Investment $14,300

Driving Impressions
Obviously, the truck is more fun to drive now than it’s ever been—but not just because of the extra 70 hp on tap. Thanks to the turbo and improved airflow to the engine, it spools faster, responds quicker going down the highway, and pulls harder up top. The best way to describe how responsive the truck feels is by comparing it to when we had Stage 1 injectors and the stock turbo. Of course, it makes twice the power now, is virtually smokeless, and runs much cooler. As we go to press, we’ve seen as much as 43 pounds of boost on the street, so we could easily be making 15 to 25 more hp than what we saw on the dyno.

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.

Planning ahead, we brought this Walbro GSL392 aftermarket lift pump with us. The high-pres

Super Duty Lift Pump Vs. Walbro
Thanks to fuel pressure dropping like a rock with the Super Duty pump still on the truck, our first full-power dyno run yielded 493 hp and 902 lb-ft (remember, limited timing advance at low rpm keeps cylinder pressure at bay in order to help the stock bottom end survive but also leads to a lower torque number). Dropping fuel pressure is a common problem for Super Duty owners running larger injectors.
Fuel Pressure (idle): 65 psi
Fuel Pressure (WOT): 20 psi

In the end, the Walbro pump’s ability to provide consistent fuel pressure made the difference. And after months of planning, we hit our mark: 502 hp at 3,000 rpm. Throughout the dyno pull, fuel pressure didn’t move off of 65 psi. The truck itself seemed more eager to run as well, pulling harder up top (we were still making 470 hp at 3,500 rpm. Check out all the data we collected during our 500hp run below.

Fuel Pressure (idle): 65 psi
Fuel Pressure (WOT): 65 psi
Peak boost pressure: 38 psi
Peak drive pressure: 58 psi
Drive-to-boost ratio: 1.5:1
Injection control pressure: 3,100 psi
IPR duty cycle: 42 percent
Peak EGT: 1,400 degrees
*SuperFlow correction factor
*30 percent load applied
*Third gear (1:1), torque converter locked
*Boost and EGT peak higher on the street

This comparison shows how—without any PCM tuning changes—the S366, Spearco intercooler, and Walbro pump upgrades yielded a 40hp gain over our old setup (modified stock turbo, smaller intercooler, Super Duty lift pump). We think it’s a true testament to how great airflow, improved air-to-air cooling, and consistent fuel pressure make all the difference in the world.

Old Setup
Peak Boost: 35 to 36 psi
Peak EGT: 1,400 degrees

New Setup
Peak Boost: 35 psi
Peak EGT: 1,200 degrees
*Same performance tune

SOURCES
Auto Meter 413 W. Elm Street Sycamore IL 60178 866-248-6356 www.autometer.com	Fleece Performance Engineering 2463N 625W North Salem IN 46165 765-676-5063 www.fleeceperformance.com
Summit Racing PO Box 909 Akron OH 44398 800-320-3030 www.summitracing.com	Randall's Performance and Accessory RR 1 Box 134 Gladstone IL 61437 309-627-2500 www.randallsperf.com
Strictly Diesel 7333 E Butherus Dr Building A-100 Scottsdale AZ 85260 480-922-8769 www.strictlydiesel.com	Gearhead Automotive Performance 979-703-7338 www.gearheadautomotiveperformanc e.com