Part Two of our old body style Ford build rolls along this month in the form of increased high-pressure oil volume and added airflow. Last time, Flynn’s Shop installed an Irate Diesel Performance OBS fuel system and 238/80 hybrids from Unlimited Diesel Performance on our ’95 F-350 project truck. This time, a Super 66 turbo gets bolted into the valley, an Adrenaline high-pressure oil pump replaces the factory 15-degree unit, and all modifications get tied together via custom tuning. We’ll rely on spot-on PCM calibrations from Gearhead Automotive Performance to keep the turbo alive and the heads anchored to the block.

01 Prior to pulling the high-pressure oil pump, the guys at Flynn’s Shop removed the injection pressure regulator (IPR). Due to the finicky nature of the IPR, it’s good practice to install a new one anytime you change high-pressure oil pumps (some IPRs act up when swapped into a different pump, while others don’t seem to mind). At the very least, new O-rings should be installed on the old IPR. This particular customer opted for the latter, as fresh O-rings are supplied with each Adrenaline high-pressure oil pump DieselSite sells.
02 Finding a mouse or rat’s nest under the high-pressure oil pump is a very common occurrence on 7.3L Power Strokes. Rodents often build homes here (or under the turbo) to escape the elements or avoid predators. The predominant problem with this is that it’s located near the engine wiring harness, which mice and rats are known to snack on and (in many cases) eventually damage.
03 With the high-pressure oil pump mounting bolts (two 10mm bolts), drive gear access cover, and 18mm drive gear bolt removed, the stock pump was pulled out of the front cover. While the factory 15-degree pump would likely support a set of smaller injectors, asking it to maintain injection control pressure (ICP) for a set of 238/80 hybrids was probably out of the question. This is why we opted for DieselSite’s proven Adrenaline HPOP in this build.
04 In addition to the ’94.5-95 7.3L Power Stroke utilizing a different high-pressure oil pump mounting gasket (left) than later models (’96-03, right), early engines also incorporated an antidrain back check ball in the block to aid cold starts. Because of this, the Adrenaline pump we ordered had to be spec’d to work in conjunction with this feature.
05 Thanks to tighter internal tolerances, increased pump efficiency, and each unit being validated on a test bench, DieselSite’s Adrenaline highpressure oil pump flows considerably more oil volume yet retains all the reliability a stock HPOP is known for. The additional high-pressure oil volume the Adrenaline provides allows it to support hybrid injectors as large as 285cc. Needless to say, the Adrenaline will be right at home supplying oil to our 238/80s.
06 Before the Adrenaline was installed, the guys at Flynn’s had to transfer the old fittings onto the new pump. The fittings are ORB (O-ring Boss), meaning the O-ring is the seal, not the threads, so getting the fittings super tight wasn’t necessary (and overtightening can actually damage the threads in the pump). DieselSite supplies two new O-rings with each Adrenaline.
07 After ensuring the drive gear was fully seated on the Adrenaline pump, the drive gear bolt and washer were installed and the bolt was torqued to 95 ft-lb. After that, the two 10mm mounting bolts were installed on the backside and tightened to 18 ft-lb.
08 From there, the access cover for the drive gear was hit with a bead of RTV and reinstalled on the front cover. A pair of 8mm bolts secure the access cover to the front cover.
09 With fresh O-rings on the IPR (supplied courtesy of DieselSite), it was installed prior to installing the Adrenaline. Then the IPR solenoid and nut (which were reused) were installed. We’ll note that a new ICP sensor (PN F6TZ-9F838-A) is also worth considering anytime you’re servicing or replacing the IPR.
10 Because so many 7.3Ls are built on a budget these days, many enthusiasts aiming to stay below the 500hp mark go the most affordable route when it comes to upgrading the turbocharger. In the case of the ’94.5-97 turbo (the Garrett TP38), several aftermarket companies offer a direct bolt-in replacement such as this one from Unlimited Diesel Performance. Called the Super 66, it incorporates a larger compressor wheel, different backplate, and 360-degree thrust bearing into the stock-based charger for improved performance and reliability.
11 The Super 66 gets its name from the use of a 66mm inducer compressor wheel. While the factory turbine wheel is retained from the Garrett TP38, an optional high-flow turbo outlet that gets rid of the EBPV butterfly valve is offered (which we selected) for less restriction in the exhaust stream. The Super 66 retails for $1,225.
12 To eliminate the failure-prone exhaust backpressure valve (EBPV), a blank turbo pedestal from Garrett would replace the stock one. This blank unit is void of the oil passages found in the OEM piece and rules out an inevitable weak link (as the EBPV is known to leak with age).
13 When it came time to install the blank pedestal, the four bolts that thread into the turbo’s center section were zip-tied in place. This is done because the two bolts nearest the firewall can’t be installed once the pedestal is bolted to the block.
14 With the pedestal’s respective mounting surface on the block cleaned up, new turbo pedestal O-rings were installed (PN F4TZ-6N653-A and PN F4TZ-6N653-B). With all oil flow to and from the turbo being internal on the 7.3L Power Stroke, the guys at Flynn’s took care to make sure these O-rings were still in place after the pedestal was set on top of them.
15 Once the pedestal was in place at the back of the lifter valley, its four 10mm mounting bolts were tightened. Also notice that a new T4 flange gasket was installed on the exhaust collector at this time (PN F4TZ-6N640-B).
16 Installing or removing a turbo on a 7.3L Power Stroke is never a speedy (or fun) process, but the guys at Flynn’s made relatively quick work of it. Then they reconnected the truck’s existing 3-inch downpipe to the high-flow outlet on the Super 66 charger, followed by installation of the factory intake Y.
17 The job of getting as much air as possible into the new turbo will be handled by a Tymar Performance intake. This intake system comes with an 8½-inch diameter Donaldson filter that flows 280 cfm, can be had for well under $200, and is a favorite in the ’94.5-97 7.3L crowd.
18 To make sure the MAP sensor didn’t trigger the PCM to de-fuel the engine with all of the new power, a Boost Relief Valve+ from DieselSite was installed. Essentially a mechanical boost fooler, it intercepts the MAP line, relieves excess pressure sent toward the MAP sensor, and allows the engine to see full boost without the PCM freaking out. In addition, two boost ports are conveniently integrated into the valve.
19 Turning their attention to the tuning that would make the truck both powerful and reliable, the folks at Flynn’s programmed the Power Hungry Performance Hydra Chip that would piggyback the PCM. To keep the Super 66 turbo from seeing too much boost (45+psi) and the heads from lifting (we didn’t install head studs), conservative tuning files from Gearhead Automotive Performance got the nod. Gearhead is well-known for keeping stock bottom end 7.3Ls alive at high horsepower, so we had them send over a handful of performance tunes designed to keep us in the safe zone.
20 Thanks to the Hydra Chip and its complementary HydraFlash software, mailing your chip to your tuner for a reburn is no longer needed. And beyond that, as many as 15 custom tunes can be programmed onto the Hydra—all of which are available on the fly. With the 238/80s conservatively tuned courtesy of Gearhead Automotive Performance, we were anxious to see how the truck drove and what kind of power it would make on our return trip to the dyno.
21 The last step of the project entailed the installation of pyrometer and boost gauges. With a pair of GS series 2-1/16- inch AutoMeter analog units added to the A-pillar, keeping an eye on EGT (up to 1,600 degrees F) and boost (0-60 psi) was now possible. With the truck being without an intercooler, boost will check in slightly higher (2-5 psi) than it would on an intercooled 7.3L, as will peak EGT.
22 After everything was buttoned up under the hood, the fuel system was primed and the engine was cranked over in 20-second intervals before coming to life (due to the injector and high-pressure oil pump change, air was present in the injection system). Once the Irate Diesel system’s fuel supply pressure was adjusted to 68 psi on the regulator, the guys at Flynn’s checked for fuel, air, and oil leaks, and then took the truck on a test drive.
23 Even though the truck’s previous owner had replaced the factory (dual-mass flywheel) clutch with some type of aftermarket unit, it didn’t take long for the new parts combination to slip it. When you’re in third gear and the clutch has no chance of holding, you know you’re in dire need of an upgrade. With a quick call up to South Bend Clutch, this 3250 dual-disc unit was at our door just two days later. Rated to handle 650 hp and 1,300 lb-ft of torque, it will be more than enough clutch to handle anything the 7.3L dishes out.
24 If you recall from Part 1, the truck made a measly 181 hp and 315 lb-ft in bone stock form. Now, courtesy of the 238/80 hybrids, Adrenaline high-pressure oil pump, electric fuel system, and 66mm turbo all being seamlessly tied together via custom PCM tuning from Gearhead Automotive Performance, the truck sends just under 420 hp and 800 lb-ft to the wheels. After documenting the 240hp gain (over stock) on the dyno graph shown, we also made a run in the truck’s Heavy Tow tune, in which it laid down a smoke-free 289 hp and 558 lb-ft—108 more hp than stock.
25 Back on Tri County Diesel’s mobile Mustang dyno, now set up at Maverick Diesel in Royalton, Illinois, the truck belted out 419 hp and 784 lb-ft of torque. The tuning file responsible for the 419hp number calls for 2.7 milliseconds of pulse width and spins the Super 66 charger up to 45 psi of boost. Just as we’d done before, all tests were performed with the ZF-5 in fourth gear.


Once everything was buttoned up, we took the truck for a test drive and quickly realized the “mystery” aftermarket clutch the previous owner installed had no chance of harnessing the Ford’s newfound power. After overnighting ourselves a dual-disc unit from South Bend Clutch, installing it, and accumulating 500 break-in miles, it was finally time to head back to the dyno to see how much power we’d gained. Trust us, if you’re looking to breathe new life into an aging 7.3L Power Stroke yet keep it rock-solid reliable, this is the 400+hp combination of parts you need. DW









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