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Compound Turbo LML Duramax

Diesel of the Week

Eric Merchant’s Compound Turbo LML Duramax

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When it comes to the 2022 Ultimate Callout Challenge, you have to give credit where credit is due. Of course, we’re talking about the competition’s new rule that competitors were allowed to compete with two trucks. Despite that rule change, a few diesel shops decided to keep it old school. In fact, five competitors opted to put together single trucks that survived all three of the weekend’s events – drag racing, a dyno pull and sled pulling. Of those, Chris Patterson saw the best overall finish of the group with a fourth place.


Eric Merchant was another single-truck competitor, and although he placed towards the bottom of the competition, his LML Duramax-powered GMC earned him a second-place finish in the sled pull on the final day of the event.

Merchant has spent nearly 30 years in the automotive industry, with the last 18 being dedicated specifically to the diesel market. He first began doing brake and alignment work in a small shop in 1993, which then led to a 10-year career at a GM dealership where he progressively rose the ranks. In the early 2000s, he bought a Duramax truck and quickly became known as a diesel guy.

Merchant Automotive was founded in 2004 and built from the ground up. Now, 18 years later, it’s the largest Duramax parts supplier, manufacturer, and service center in the world. All the while, Merchant has been fine tuning his competition truck he bought in 2002 nicknamed “Ol Blue.”

“We don’t really have the hardware to compete with the guys at the top level, and that’s okay,” Merchant admitted. “We just haven’t put the same level of commitment into as them and we’re usually just sled pulling all summer.”

Nonetheless, Merchant’s Duramax is pretty impressive and certainly nothing to sneeze at. The engine is built around an LML block, with LBZ-based heads, an internally balanced Callies crankshaft, Wagler rods, Diamond pistons, and a Wagler alternate-fire camshaft. The fuel system is full S&S.

“We’ve got 350% injectors and there’s two 14mm pumps,” he says. “On the control side we have a Bosch Motorsport ECU. We’re still running the Allison transmission with it and that has it’s own challenges, and it’s probably more headache than it’s worth. But the PCS controller seems to help that quite a bit.”

As for the turbo setup, Merchant has run the same setup for the last few years and has seen success despite using “old” hardware. A 104mm atmospheric turbo compresses and force-feeds the air into a smaller BorgWarner 76XSE on the manifold side.

“It’s nothing exotic and they’re heavy wheels, but they’ve been keeping alive for years,” he says.

Without nitrous, Merchant says that truck has produced around 1,800-hp on an engine dyno, but currently sits around 1,500-1,600 hp with the current setup. Unfortunately, on dyno day, Merchant sheered all of the engine’s converter bolts and wasn’t able to make a full pass. The result was 1,270.8 hp.

The team with Eric at UCC worked to get the truck ready for the sled pull, where they expect to shine, and shine they did! Merchant was able to perform up to his standards on Sunday’s sled pull event, where he earned himself a second-place finish with a pull of 297 ft.

Diesel of the Week is sponsored by AMSOIL. If you have an engine you’d like to highlight in this series, please email Engine Builder Editor Greg Jones at [email protected]

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