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Project Paw-Paw: Part 12

From a performance standpoint, we wrapped up Paw-Paw’s long journey from bone-stock, 160rwhp retired farmhand to 567rwhp Camaro killer in Part 11. Now it’s time to see if the inconspicuous old Ford is more than simply a 13-second hot-rod. For the purpose of proving the truck is still as versatile and functional as it was the day it left the assembly line, consider this installment the exclamation point of the series. As a result of all our careful parts planning, we have no reservations about hooking Paw-Paw to our 10,000-pound travel trailer and hitting the road—and here’s why:

Throughout the course of the build, we made it a point to select a combination of parts that wouldn’t sacrifice the truck’s ability to tow at the expense of making big power. As for the injectors, we knew Unlimited Diesel Performance’s 350/200 hybrids were big, but we also knew that Gearhead’s spot-on PCM tuning could pull enough fuel out of them to make them tow-friendly. Picking a turbo that could support 600 hp yet still spool well on a 7.3L, Fleece’s billet S468 checked all the boxes. Then, in order to bring the S468 to life sooner, John Wood spec’d a torque converter with a slightly higher stall speed when he beefed up our transmission. Finally, with axle wrap being the last thing we wanted to face with a trailer behind us, One Up Offroad got the call for a set of its industry-leading traction bars.

In our first trip out with the travel trailer in tow, everything we’ve done to the truck seems to work together seamlessly. There’s much more pulling power on tap (obviously), the engine and transmission stay cool, and we see above-average spool up from the S468. You can check out our initial towing impressions below, as well as the last two (tow-related) accessories we’ve added to the truck.

New Electric Trailer Brake Controller

Tekonsha Electric Trailer Brake Controller

In the trailer brake controller game, Tekonsha is a household name. To usher Paw-Paw into the modern age, we scrapped the archaic unit mounted under the dash with Tekonsha’s Prodigy P2. The Prodigy P2 is a self-leveling, proportional trailer brake controller, which means it produces stops that are directly proportional to the tow vehicle’s rate of deceleration. It’s designed to work in conjunction with one to four braking axles, features an easy-to-read digital display and only has 3.6 milliamps worth of draw when not in use.

As Simple as It Gets

Tekonsha Prodigy P2

Thanks to our F-350 leaving the dealer with a factory-installed tow package back in the fall of 1996, wiring up the Prodigy P2 was a plug-and-play affair. To make things easier on folks with vehicles that weren’t factory-prepped to accommodate a brake controller, Tekonsha offers vehicle-specific adapter harnesses that seamlessly tie into the OEM harness under your dash.

Barely Breaking a Sweat

Pyrometer EGT Analog Gauge

Of all the gauges we installed in Part 10 (and the 12+ parameters we can view), the pyrometer is the one we’ll be paying the most attention to while towing. When we initially set out with the 10,000-pound toy hauler behind us, we set the Hydra Chip to tune 1, our Heavy Tow file. With roughly 200hp worth of fuel pulled out of the truck’s bottom line, this tune rarely pushed exhaust gas temperature (EGT) past 1,100 degrees F. Remember, 1,250 degrees is generally considered the “hot” mark for 7.3L mills, so Gearhead obviously nailed it with this tune in terms of engine safety.

Custom-Tailored Tow Tune

Tow Tune Power Stroke Diesel

Looking for a tad more pulling power, we bumped up to our second tow tune (position 4 on the Hydra Chip). Custom-built for our exact combination of parts and this specific trailer, this calibration doesn’t lock the torque converter until third gear and 36 mph (vs. 32 mph in other tunes). Holding the lockup event off until more engine speed is on tap ensures the S468 stays in its happy place during the shift (i.e. no falling under the charger due to a lack of rpm and boost). Tune 4 also brings more fueling into the equation, but not enough to worry us. So far, we haven’t seen EGT crest any higher than 1,200 degrees F in this tune.

Transmission Temp Peaks at 150 Degrees

Transmission Temperature Analog Gauge

Contradictory to what some might’ve expected, running a looser converter along with a big single turbo doesn’t seem to bother the built E4OD automatic, even with our 31-foot wind sail in tow. Thanks to John Wood’s efficient transmission build as well as the addition of a 37-row, stacked plate (5R110-intended) Mishimoto transmission cooler, ATF temp never exceeds 150* F—and it takes a lot of effort to get it there. In fact, the four-speed slushbox spends most of its time operating at 140 degrees or less.

Keeping the Big Single Turbo Happy

AeroForce Technology Interceptor Gauge

Vitals viewable on the AeroForce Technology Interceptor gauge all looked good during our tow test. Obviously, there is always more boost on tap with a 10,000-pound load behind the truck than when it’s empty, but our custom-tailored tow tunes intentionally hold out each gear a little longer to ensure this is the case. The entire combination (namely the looser converter and custom tuning) keeps the S468 charger up on boost at all times.

Mirror Extensions

CP Addict Mirror Extension Kit

We love the idea of retaining Paw-Paw’s smallish factory side-view mirrors, but they leave much to be desired in the way of keeping track of a trailer that’s considerably wider than the truck. Not wanting to abandon the looks of the original mirrors, we did the next best thing: we bought an Extend-A-Mirror kit from CP Addict. Now, each mirror can easily be extended out an additional 5.5 inches and reverse maneuvers are no longer a chore.

Easy Adjustment, Factory Look

Ford Mirror Extensions

The Extend-A-Mirror kit works by relocating the original mirror head to the supplied 8-inch long aluminum extension arms. A two-piece plastic head extender bracket attaches each mirror head to the factory mirror support. The extension arms are locked in place via a bolt with a ribbed-edge plastic knob.

Back to Work

1997 Ford F-350 Towing

Putting Paw-Paw to work with all the newfound power is a totally different experience than it used to be. For one thing, the truck is faster now with a travel trailer behind it than it was empty at the stock power level. Think about that! With all the added fueling made possible by the bigger injectors, high-pressure oil pump, electric fuel system and custom tuning, the engine is very responsive and as a result the old Ford is much more eager to get up to speed. While picking up speed, the transmission’s upshifts are crisp but not overly firm, EGT stays well within check and the truck’s entire setup feels rock-solid and well-rounded.

An All-Purpose Vehicle

Ford Power Stroke Diesel Tow Test

Truly multi-faceted now, Paw-Paw can send a pavement-peeling 1,100 lb-ft of torque to the wheels or be used as a fairly fuel efficient commuter. It also offers us four-wheel drive in winter (and any other time we need it), hauls everything we can fit in the bed and—as is the case in this installment—can even tow anything we want. The best part about all of the above is that nothing has to be physically changed on the truck in order to transition from work to play. Nothing. By simply selecting the appropriate tune on the Hydra Chip, Paw-Paw can become a cool-running, docile tow-rig, a fun daily driver or a 13-second sleeper in less than a second.

Miss the part where we laid down 1,100 lb-ft of torque on the dyno and ran 13’s at the track? Project Paw-Paw’s sleeper status was officially confirmed in Part 11.

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