7.3L Diesel Dyno Day Was a Black-Smoke-Filled Day of Fun


We here at Diesel Army are the newest member of the Power Automedia family. As such, we have been getting a lot of support from our team of automotive performance experts here on staff. So, we figured what better time to convince them that we need to play with our toys, errrr scratch that, we mean – um, give our readers some good hardcore action. After borrowing (ok, stealing would probably be a better word for it) the keys to the shop, we took full advantage and setup the very first Diesel Army “Dyno Day” to be featured in our series of upcoming dyno day events.

In the Power Automedia garage, we recently installed a Dynojet 224xLC chassis dyno. This is a 2,000 horsepower, 200 mph dynojet in-ground dyno.

Dyno-day copy

Photos By Mike Alexander

So, with the shop left to our own devices, we figured we would start out this series with a real world, high-mileage dyno day featuring some local Fords that really get used and driven daily. To sum up that day in three words, we’d have to go with smoke-churning, big, and badass! We captured the day with both photos and video, so make sure to check out all of the mini-feature vids as well as the dyno results on each participant.

Behind the 7.3L Power Stroke

Part and parcel of the greatness of the seven-three was its use of hydraulic electric unit injectors (HEUI), which greatly increased oil pressure and made the truck capable of handling the loads of power at its behest.

  • Bore: 4.11 inches
  • Stroke: 4.18 inches
  • Displacement: 444 cubic inches (7.3L)
  • Injection: Direct Injection (HEUI)
  • Turbo: Single Turbo/non-intercooled

1994-1997 DIT

  • Base Horsepower: 210 hp at 3,000 rpm
  • Base Torque: 425 lb-ft at 2,000 rpm

1999 -2003

  • Horsepower: 235 to 275 hp
  • Torque: Ranged from 500 to 525 lb-ft

Brief History On The 7.3L DIT

After years of success with the 6.9 and later 7.3L indirect injection diesels, Ford and Navistar decided it was time to revisit the design in the early ’90s. The new engine would be the first computer-controlled diesel in the light duty segment. While the displacement would remain the same (7.3L), this was in fact an entirely new engine. Ford probably didn’t even realize at the time that this new and improved 7.3L would become one of their hottest engines and still something highly sought after, even a decade after they discontinued production.

The 7.3L used a unique injector co-developed between Caterpillar and International. The revolutionary injector used hydraulic multiplication to inject fuel in excess of 23,000 psi directly into the cylinder. At the time, most competitors were lucky to see 18,000 psi through an injection pump. To gain the hydraulic advantage, the 7.3s use a High Pressure Oil Pump (HPOP) that is fed by the low pressure oil pump, which increases the pressure up 3,000 plus psi at high demands.

All of the Direct Injection engines were Turbocharged (DIT) and were introduced mid-year in 1994. The original engines were in the last years of the Old Body Style (OBS) trucks from 1994 to 1997. The turbocharged 7.3L engines were non-intercooled (had what we would consider low boost pressure now, but low to mid teens was high boost pressure back then) and were fully computerized. If the camshaft position sensor (CPS) went out, the engine died.

Unlike some later computer-controlled engines from other manufactures, these engines live and die by the computer. Later there was a slight revision of the engine in 1999 when the new Super Duty was introduced (model year 1999, calendar year 1998). The Super Duty’s featured higher boost pressure and were intercooled. These engines were still rock solid and extremely dependable. That’s one of the reasons they are so highly sought after to this day.

Enough Of The Jiber Jaber – Let’s Talk Dyno!

For the high mileage, daily-driven 7.3L-centric dyno day, we wanted a group of true work trucks that get used day in and day out. We cast a net over what is called the Inland Empire in Southern California (an area that is an hour away from the beach and on the other side of the mountains). After getting some great feedback, we narrowed down our picks to six unique individuals with some great trucks. Most are local friends and work at different So Cal diesel shops, including such die-hard diesel organizations as Lewis Built PerformanceAxxis Off Road, and American Diesel.

Brandon Shade’s 2000 Excursion

Quick Look At The Excursion

  • Stage 2 injectors
  • DP tuner
  • 4.88 gears with Detroit Locker diff
  • Fabtech 6-inch lift kit
  • Mileage: 156k
  • Best run: 259 hp, 509 lb-ft of torque

First up, we have Brandon Shade in his 2000 Excursion. This SUV came loaded for bear with a bunch of parts and components: Banks quick-spool housing with a bigger wheel, stage 2 injectors, Airaid intake, and a 4-inch MBRP straight pipe with 5-inch tips.

Elsewhere, Shade installed a Fabtech 6-inch lift to clear the Procomp 16-inch wheels and 37-inch Xtreme Mud Terrain tire combo. To keep this combination streetable Shade upgraded to a set of 4.88 gears front and rear with a Detroit Locker heavy-duty limited-slip. This combination allows him to cruise at freeway speed at a reasonable rpm, but gives him all the extra torque needed when this bad boy heads off the pavement. To cut down on axle wrap, he installed a set of Lewis Built Performance traction bars.

Other goodies include: cowl induction hood, a 9900 WARN winch, seven PIAA amber lights, a CARR light bar, strobe lights on all four corners, and a cargo rack. Inside, we found it had ISSPRO gauges, and even a police scanner and CB radio.

When it came to the dyno, Shade’s Ford put out some respectable numbers: 258.55hp/509.07 lb-ft of torque on the first run, and 254.5/504.65 on the second.


Ed Hatcher’s Bio Diesel F-250

Quick Look at the F-250

  • Bio diesel fuel system
  • Dyno Trans Super Duty Transmission
  • Detroit Locker rear differential
  • Dana 60 High Steer Kit with Heim joints
  • Mileage: 235k
  • Best run: 221 hp, 410 lb-ft of torque

Next victim was Ed Hatcher, whose ’97 F-250 brought along a different kind of diesel: one with a bio diesel setup. With fuel prices continuing to climb and who knows what the future holds, Hatcher opted to take the fuel issue into his own hands. He upgraded all of his fuel system with a driven diesel fuel kit and fuel bowl delete kit. Then he set up the electronics necessary to switch to regular diesel just before he turns off (keeping his lines from clogging). Now, Hatcher uses homemade batches of diesel using everyday vegetable oil (another reason to love fast food). Hatcher says the only real drawback is that sometimes, while driving it “makes you hungry.”

Hatcher’s ride has a good look to it thanks to the 6-inch lift with 35-inch tires and Moto Metal wheels. On top of everything, the truck is sporting a custom-built roof rack with 3 HIDs up front. On the underside of things, a Dana 60 High Steer Kit with Heim Joints was installed along with a set of rear Lewis Built traction bars.

Under the hood, the 7.3 was being tweeked by a 6-position chip from TS Performance. The power was then being sent through a custom-built Dyno Trans transmission to a Detroit Locker rear diff which then was able to turn our rollers and produced a respectable first run of 220hp/409 lb-ft of torque, and a slightly better second run of 226/426 respectively.

After Hatcher’s runs, we were most assuredly famished (thanks bio-diesel) and had to take a quick break for some grub. We reconvened an hour later, our stomachs settled and thirsts quenched with water and energy drinks to see what the rest of the day would hold.


Chris Lewis’ 1996 F-350

Quick Look At The F-350

  • 2001 F-350 front axle conversion
  • Lewis Built Performance 11-inch Lift kit
  • Riffraff 6637 intake
  • 1-1/4-inch heim joint crossover
  • Mileage: 270k
  • Best run: 152 hp, 307 lb-ft of torque

Chris Lewis’ entry brought us a six wheeled beast. Lewis, being an avid fabricator and owner of Lewis Built, constructed and installed homemade parts like the 5-inch straight axle conversion and 11-inch lift kit. Add to that a set of 37-inch Super Swamper tires, and this was a truck you couldn’t help but admire for all the care, cost, and effort put into it.

With the suspension finally finished, Lewis is planning to overhaul the engine next. He decided to participate to get a good baseline to see where the old girl is nad figure out what bugs to work out first. The truck is currently running a TS Performance 6-position chip as well as a Riffraff 6637 intake.

Lewis’ first run produced 147 hp and 298 lb-ft of torque and the second pull yielded 152 hp and 307 lb-ft. Curious to see what his truck would do without its tuner he removed it, and laid down a mere 78 hp and 173 lb-ft of torque. At 256k this engine still has some life in her, but certainly needs some lovin’. Lewis is pretty sure that he has a couple of injectors out and this pretty much proved it. Fortunately, he is “currently building a bulletproof motor for it,” and will have it back up to snuff in no time.


Brian Hartley’s 2002 Excursion

Quick Look At The Excursion

  • Edge CTS Diesel tuner
  • MBRP 4-inch stainless exhaust
  • S&B cold air intake
  • Stock turbo producing up to 23 lbs. of boost
  • Mileage: 100k
  • Best run: 289 hp, 523 lb-ft of torque

Brian Hartley, Owner of Axxis Off Road, made sure his Excursion was ready to go for the Dyno Day. Big, white, and the “youngest” of the bunch, the SUV came ready for the showdown.

Hartley had his Excursion equipped with an Edge Products Evolution CTS Diesel module to give him the performance he wanted, but more importantly, to monitor the vitals. Under the hood, the only upgrade he did was to install a S&B cold air intake.

Giving the truck an imposing appearance not to be reckoned with, Hartley added three-inch lift blocks, Procomp shocks, and Weld wheels with Dura Trac tires.

However, Hartley’s ride wasn’t always tricked out, about two years ago, Hartley and his friends were headed down to Mazatlan to have a good time. Out of nowhere, a semi-truck came roaring from the side and plowed into the SUV and trailer, destroying just about everything.

Rather than collect the insurance and go about their merry way, Hartley and his friends took the time out – about six months worth – to do the bodywork and fabrication. After seeing its pristine appearance, we couldn’t help but admire the resourcefulness and talent the guys put to use on the project.

On the dyno, Hartley did a first run of 289 hp/523 lb-ft of torque. During the second run, he had a boost leak but still managed to turn in a decent number at 264 hp/493 lb-ft. The first run ended up being the best of the day up to that point, but there were still a couple of 7.3s left to put to the test.


Jerry Schuman’s 1997 F-250

Quick Look At The F-250

  • Mostly stock
  • 3-inch Magnaflow exhaust
  • Edge Evolution Tuner
  • Mileage: Highest mileage truck tested at over 356k miles
  • Best run: 239hp, 523 lb-ft of torque

The most spartan of the Power Strokes we had on the dyno, Jerry Schuman’s F-250 rolled into our garage at 356k miles and with hardly an aftermarket part to its name. Nonetheless, it is a true work truck and daily-driver that we were after for this round of testing.

The only upgrades consisted of a 3-inch Magnaflow Cat-Back kit and an Edge Products Evolution tuner. Everything else, says Schuman, was “just tune-up or maintenance.” And with a nice and reliable work truck, we can’t fault the guy for keeping it simple now, can we?

Yet Schuman claims that this truck is nothing to be scoffed at, even though he’s taken lots of flak for keeping it as long as he has. “That truck has towed home every one of my friends at least once, when either they blew up their truck, got in a car accident or got wrecked while off-roading. So the name that has been given to the truck is ‘Old Faithful’ because she has always been ready to roll.” Old Faithful gave it everything she had on the dyno that day, with a best run of 239 hp and 418 lb-ft of torque.

Now that the truck has passed hands to a friend of Schuman’s, its legacy of strength, power, and reliability is ready to live on. Let’s just hope that the new owner understands he doesn’t need any fancy bells and whistles to keep Old Faithful running strong.


Paul Christensen’s 2000 F-350

Quick Look At The F-350

  • 4-inch straight exhaust with 8-inch tip
  • 20-inch BMF wheels
  • 35-inch Toyo M/T tires
  • Over 25 lbs. of boost in 3rd gear
  • Mileage: 256k
  • Best run: 274hp, 467 lb-ft of torque

Last but not least, there was Paul Christensen’s 2000 F-350. This big red rig, rolling on 35-inch Toyo M/Ts and 20-inch BMF wheels, had no problem climbing on to the dyno to see where it stood amongst the pack.

The charger is able to produce 27 lbs. of boost, thanks to the extra fuel supplied by the  TS Performance chip – the same one found on Chris Lewis’ truck – and a cold air intake kit. The F-350 was having fun all day in the sun, whether it was out doing burnouts on the nearby street, or putting up strong numbers on the dyno’s monitor.

On the first run, Christensen ran 274 hp with 467 lb-ft of torque. A second run produced the same numbers, but they were good enough to put the man and his machine in third place overall for the day when measured against the torque numbers of the other participants.

The amount of smoke billowing out of the 8-inch tip was staggering to say the least (especially on stock injectors). Our Group Editor and photographer, Mike Alexander, could attest to that first-hand when it almost completely engulfed him as he was snapping pictures of the day’s festivities.


The End Of Diesel Army’s First Dyno Day – But The Start To The Series

If you were keeping track, here is the order, from highest to lowest according to torque:

  • PCTBrian Hartley’s ’02 Excursion, 523 lb-ft
  • Brandon Shade’s ’00 Excursion, 509 lb-ft
  • Paul Christensen’s ’00 F-350, 466 lb-ft
  • Ed Hatcher’s ’97 F-250, 426 lb-ft
  • Jerry Schuman’s ’97 F-250, 413 lb-ft
  • Chris Lewis’ ’96 F-350, 306 lb-ft

We want to give a special thanks to all the guys who came out for this event. As we mentioned earlier, this is just the first in a long series we plan on doing until management decides we have to start cleaning the soot off the walls. So stay tuned to Diesel Army and check us out on Facebook – come back often to see what other fun tricks we have up our sleeves.

About the author

David Chick

David Chick comes to us ready for adventure. With passions that span clean and fast Corvettes all the way to down and dirty off-road vehicles (just ask him about his dream Jurassic Park Explorer), David's eclectic tastes lend well to his multiple automotive writing passions.
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