Duramax Beast Mode

When Willie Lewis first started tinkering with his 2008 Duramax LMM it was just another diesel truck pounding the dirt roads of Texas. When you work on diesel machinery in the oil fields, it’s pretty much a prerequisite that you drive a diesel truck. He had already put together a 2005 Dodge Ram with the very popular 5.9L Cummins, which cranked out a pavement-shredding 750 rear wheel horsepower.
It wasn’t long before he noticed almost everyone in North Texas was driving a modified Cummins. Willie isn’t the kind of guy that follows a crowd, so he got the urge to break away from the mold and try something different. His LMM was the answer and he hadn’t seen anyone else building them up in his part of the world.

All In

With his knowledge of how a diesel engine ticks, he wasn’t afraid to dive into a brand new truck and start making the modifications he knew would produce the performance he was after. Like every diesel enthusiast, Willie’s addiction started with a simple intake tuner and exhaust.
If you talk to anyone in this industry they can vouch for Willie. Diesel performance is an addiction and some of us have to attend monthly meetings. The first time you mash on the throttle and feel the torque trying to suck your eyeballs through the back of your skull, yeah that addiction never goes away.
The problem is, you bolt a couple thousand dollars worth of parts under the hood and it feels great. However, after a couple of months you get used to it. The only way you can get that fix again is to spend some more cash and improve on what you already have.

Constant Need

Willie is no different in this department. Those initial bolt-on parts only seemed to satisfy for a while, but once he got used to the power he needed to feel that rush again. What better way to get what he wanted, than to bolt-on some compound turbos and bigger injectors?
With the new parts installed, it was only a matter of time before the stock internals began showing their distaste for the increased power. Willie knew the only way to solve this was to equip the factory block with a fresh set of Carrillo Rods and a shiny new stack of cast Mahle pistons. With the engine completely built, it was ready to handle any beating he wanted to throw at it.
The factory transmission was never going to live under these strenuous power levels and Willie took a whack at building it himself. He had built the engine himself with help from Kotzur Racing Engines in San Antonio, Texas, who did all of his machine work, so he figured the transmission should be easy. In retrospect he probably should have called Dimitri sooner. After destroying what he had built himself, he was offered a helpful hand by Dimitri Millard who used his extensive knowledge of the Allison transmission and a pile of parts from Sun Coast Transmission to make sure Willie’s transmission could handle what he was fixin’ to throw at it.

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The Big One

One thing led to another and he ended up attending the Super Bowl of Diesel Performance. He never would have thought it was possible, but his lovely fiancé had sent in the voting form without telling him. A couple of months later he got an email saying he and his truck had made the cut.
Arriving in Arvada, Colo., he met up with Tony Rizzi from Lead Foot Diesel Performance who was the only other Duramax owner in the competition. They hit it off right away knowing birds of a feather flock together. After a week of competing in the mile high club they had become close friends. Willie promised Tony that when he was ready to take the truck to the next level he would be the only one working on it.
It was almost a year later when that menacing itch started gnawing at the back of his mind again. Willie needed more, and he needed it now. A quick call to Tony’s cell phone rapidly evolved into an elaborate plan, which meant Willie would be driving the truck 938 miles to the Lead Foot Diesel Performance’s Race shop in Georgia, where Tony works his magic.

Getting Serious

The modified VGT turbo in the valley and the Borg Warner low pressure charger were swapped out for a Garrett 4202 in the middle of the engine and a Garrett GT5533R hanging off to the side. After a couple of years of bolting different parts on and taking them off and pulling the engine in and out, the wiring harness was a mess.
The first thing Tony had to do was yank the entire engine harness out of the front of the truck to get the little butt connectors and un-used factory sensors eliminated. With the wiring harness cleaned up, the truck’s engine bay was starting to look more like a show truck than a competition built torque monster. Now he had bigger fish to fry: those two massive turbos needed a home under the hood instead of in boxes in the back of the truck.
After a couple weeks of mock-up, ordering numerous clamps, flanges, piles of 304 stainless tubing and a pair of massive external gates from TiAL, Tony’s creation was beginning to take shape. His vast knowledge of how to use waste gates to reduce cylinder pressures and better drive the low pressure charger is the reason Willie decided to employ Tony for the job in the first place. The LFDP fabricator wouldn’t give us all of his secrets, but he explained enough that we know he is on to something here.

Finishing Touches

Once Tony had the turbos and waste gates all piped in the way he liked it, the tubing was sent out for a brilliant coat of electric blue powder. There was some work that needed to be done on the fuel system though and with the turbo kit out of his way, this was the perfect time to tackle a few smaller projects.
The fuel side of this build includes a set of Twin CP3s fed by two Air Dog 200-gallon-per-hour lift pumps. All of that fuel is then fed into a set of 100 percent over stock Exergy Injectors. The entire laundry list of aftermarket goodies is fine-tuned and controlled by custom EFILive tunes from Nick at Duramax Tuner. After many hours of data logging and driving, the tunes were to the point Tony felt comfortable letting the truck make its long trek back to North Texas from Georgia.

Clean Impression

Willie booked a plane ticket and arrived at the Lead Foot Diesel Performance headquarters to see what his hard-earned dollars had gotten him.
When Tony popped the hood, Willie couldn’t believe how clean everything had turned out; the piping flowed gracefully through the engine bay and the previous clutter from the wiring harness was gone. The truck ran so smooth you could barely tell it was running. He hopped aboard and drove around with Tony, while discussing everything that had been done to the truck and what needed to be done with the tuning once the truck was back in Texas. Elevation changes have a lot to do with how a truck is tuned—especially on a Duramax engine where the mass air flow sensor has a lot to do with the fuel timing tables. Once the truck left Georgia at sea level and got back to Willie’s home town, it would have to be tuned a little different.

Getting Her Home

Willie headed out on the 900-plus-mile drive home and took extra care to hand-calculate the fuel mileage. He called LFDP after he made it home and reported a 19.5 average for the trip. Not bad for a truck making close to 1200 horsepower at the rear tires! Be on the lookout for Willie’s truck at a sled pull near you this summer.