The Benefits Of Diesel Power Know Few Bounds
There are few things whose purposes are as different as a Marine-issue Hummer and a Nordic ski boat. One is for land-based operations; the other is for water-based fun. But as different as they are, these two examples do have some things in common: they are both powered by Duramax engines from Pacific Performance Engineering.
We’ll tour these two offbeat examples one at a time. First, the beast, then we’ll take a look at the beauty.
Produced by AM General and known officially as the “High Mobility Multipurpose Wheeled Vehicle” (HMMWV), this vehicle is known far and wide simply as the “Humvee.” A prime example of your tax dollars in action, the Humvee was designed in the early 1980s as a replacement for what had essentially been offshoots of the iconic World War II Jeep. What was ultimately delivered was a Jeep on steroids.
The Humvee was designed to get our troops over rough ground quickly and safely. The wide, and therefore, stable stance combines with a long-travel suspension system that still keeps the center of gravity low; all combine to make the Humvee a killer off-road vehicle. And we mean that in all senses of the word.
At least that part of the equation was a good idea. The power train? Not so much.
We can’t think of a good reason why all the Humvees weren’t equipped with diesel engines, but while some came with the 6.2 L diesel engine, some early models had a 400ci gas engine. If there was ever a vehicle that screamed out for hard-digging, turbocharged diesel power, it’s the Hummer.
This 1987 Humvee started out as a United States Marine Corps issue rig that PPE boss Joe Komaromi bought at auction. He has transplanted many Duramax engines into vehicles that were never meant to have diesel power, so this was his chance to put one of his hardcore Duramax engines into a vehicle he felt was a perfect match for it.
Whereas the original diesel-engined Humvees produced barely adequate horsepower, the 6.6L engine that Komaromi added to his would be in the 600-hp range with 1,280 lb/ft of torque.
Using a 2007 block, Komaromi bored it .20 over, balanced it and then installed a PPE crank, Carrillo rods and PPE pistons. On top, a set of PPE Stage II heads, which have been ported, polished and equipped with dual springs and titanium retainers, are held in place with ARP head studs. A special PPE camshaft is also used. The final tally comes to a 15.5:1 compression ratio.
Adding the combustibles are 60-over, eight-hole PPE-modified Bosch Motorsports injectors that are fed with a PPE lift pump. The pressure coming from the Garrett GT4094R turbocharger is cooled with a PPE intercooler before entering the engine, but it’s first cleaned with a custom, 5-inch PPE air intake system/cleaner that utilizes the stock air intake duct.
Providing the brain for this beast is a PPE Hot + 2 E.T. programmer, while PPE manifolds and up pipes route the spent fuel through the turbo and out by way of a custom exhaust system. Off-road is no place to be short of power, whether horse or electrical, so a pair of 120amp alternators gives much-needed redundancy.
Raw power is great, but getting that power to the ground is just as important, so a six-speed PPE Stage 5 Allison transmission was chosen. It features a PPE billet locking 1700rpm stall converter and is cooled with a quartet of PPE electric fans that blow over the tranny cooler.
A custom driveshaft with 1410 billet universal joints connects the transfer case to the axle housings. A Detroit Locker is in the rear, while an E-locker can be found in front. The gear ratio at both ends is 2.53.
Also at both ends is a set of hard-anodized H2 wheels that have been wrapped with dirt-worthy BFGoodrich Baja T/A rubber.
Komaromi was all about leaving the Humvee’s exterior and interior pretty much the way he got it, but there were a few things that needed to be changed. Gone is the stock gauge cluster, and in its place is one from a GMC 2500HD diesel truck. PPE turbo boost pressure, EGT and fuel rail pressure gauges were added, as well. Also used were the electronic push-button 4×4 switches from the truck, while the PPE “Hot Rod” wiring system works with the stock system to connect all the electrical dots, including the ECU.
Komaromi even made sure that the air conditioning and cruise control were operational. After all, there’s roughing it, and then there’s just being ridiculous about it. Joe likes the finer things in life (but then, who doesn’t?).
This Humvee is an example of American know-how and American strength. The vehicle itself was designed literally for the rigors of war, and the Duramax engine that PPE has installed into it is capable of truly unleashing the potential of the AM General design.
This beast is what you want to be in if the fur starts flying, and speed and brute strength may mean the difference between winning the day or not.
There are few things nicer than cruising the Colorado River in an open boat (when it isn’t 120 degrees, that is). But while many ocean-going vessels are diesel-powered, the same can’t be said for freshwater boats that are fewer than 25 feet long.
That was why Gary Posey called PPE and talked Komaromi into the idea of installing a Duramax into his 21-foot Nordic. Posey—who has had PPE install a Duramax into his own Humvee (a yellow one) and is aware of Komaromi’s classic Chevy pickup and other swap projects that PPE has done—loved the way the Duramax worked in his Humvee.
So why not his boat? It didn’t take too much convincing to get Komaromi to agree to take on the project.
Using a 2004 LBZ Duramax as his starting point, Komaromi ported the heads and held them down with a set of ARP head studs. A Garrett DCX4508 water-cooled turbo sits on a custom stainless steel turbo pedestal, which is also water-cooled and provides 50 pounds of boost pressure.
With all that water rushing by, Komaromi decided to use it to cool the intercooler, so he made one out of super nickel stainless steel and equipped it with twin zinc anodes to work with the water. The result is that the air entering the engine is a mere 80 degrees. The water that is used in cooling the various pieces exits out the wicked-looking exhaust pipe.
Measuring out to 5 inches, the stainless steel “stinger” system gets hot, but the entire engine/exhaust package is Coast Guard-legal, since no piece gets hotter than the legal limit of 400 degrees.
But here is where it gets weird: The setup uses a transmission, too. Yep, Komaromi designed a special adaptor to mate the PPE stage 5 Allison transmission to the Inco stern drive. Weirder still, there’s no torque converter, but there is a straight-through coupling of the engine to the tranny to the stern drive. This works because the action of the water against the five-bladed, 30-pitch prop acts like the converter. Using the transmission and the torque of the diesel engine allows that the stern drive is actually 1.15 overdriven, while a standard stern drive system uses a 1.15 under drive. The steering is power-assisted with dual rams for total control.
All of this means that the Nordic has a top speed of more than 100 mph at 3,800 rpm, but Posey says the Nordic can cruise comfortably at 60 mph—a speed that more suits his retired, laid-back lifestyle. And thanks to the 7 mpg the boat now gets, compared to the 2 or 3 it used to get, it can also do that cruising for a considerably longer period than a standard boat. That fuel is contained in a 50-gallon belly tank.
The rest of the boat is as it came from Nordic, except for a few additions to the dash that few other boats can boast: turbo boost pressure, RGT temp gauges and the PPE monitor.
Upon testing, Komaromi found that the diesel’s grunt and the transmission’s gear ratios put the boat up on plane quicker than anything he’s ever experienced. He says that the power that the engine produces pushes the boat to scary speeds, and the extra mpg gives the Nordic the legs to go on long trips without worrying about fuel. The setup really puts the pleasure in pleasure boating.
As a retired UPS executive, Posey now kicks it in his river-side home, but when he wants to elicit stares and countless questions, all he has to do it take the water in his beautiful—and one of a kind—Nordic.
This is in the December issue of Diesel World.