2008 Turbocharged 6.7L Cummins Engine - Engine Builder Magazine

2008 Turbocharged 6.7L Cummins Engine

Bought on Craigslist with 120,000 miles on it, CGT Diesel revamped a 2008 4-door short bed Dodge 3500 and its 6.7L Cummins engine to the tune of 900 horsepower. Find out what went into the diesel build.

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Searching Craigslist for a truck, Jack Gulbrandsen came across a second Gen Dodge for $5,000. As a senior in high school looking to have fun and modify it, he took the plunge into owning a diesel.

“This thing was beat up and haggard, but it had a 5.9L Cummins and I knew that’s what I wanted based on everything I had seen on social media and in magazines,” Gulbrandsen says. “As a 17 or 18-year-old kid, you don’t have a ton of money to pay someone to work on it. The thing had issues all over the place, so I just slowly started tinkering with it on my own. I didn’t know what the hell I was doing at first, but I got to the point where I was able to fix things pretty well.”

Jack’s passion for diesel trucks grew, and along with a few buddies, they went looking for somewhere to practice their new hobby.

“My buddies and I didn’t have a shop, but my friend’s dad owns a construction company and he had a shop for storage,” Gulbrandsen says. “It would be a school night and we’d be at the shop till 5:00am trying to figure out how to put a Bank’s big head wastegate on my truck to make 2-lbs. more of boost so we could go test it and see how fast it was. We were doing that stuff on and off for about a year. Pretty much every dime I made I put back into that truck.”

The true point of no return for Jack’s plunge into the diesel industry was deciding to enter his Dodge into a local sled pull event.

“I had my second Gen Dodge with the Bank’s wastegate and a smarty on it,” he says. “I had manual swapped it and the sled pulls were in town. I went down there and entered into the stock class and I pulled 278’. I remember after being in the seat doing that, it was over for me. I loved it.”

Jack and his buddies eventually got to a point where their friends and acquaintances with diesel pickups started asking them to do work on their trucks too.

“We kind of took off doing that stuff, but my buddy’s dad finally kicked us out of his shop, so we moved to a 500 sq.-ft. shop and formed CGT Diesel,” Gulbrandsen says. “Originally it was three of us – our last names are Christiansen, Gulbrandsen and Taylor. However, Christiansen got hired on with Cal Fire, so he left the shop. Then, my buddy Garrett Taylor, who is a really good fabricator, started his own fabrication shop, so it just ended up being me.

“I stayed in the 500 sq.-ft. shop for a little more than a year, which was pretty small, so I took the chance on renting a 6,200 sq.-ft. shop right down the road and we took off from there.”

CGT Diesel was started in March 2017 and moved to its current 6,200 sq.-ft. location in Ukiah, CA in the fall of 2018. Today, the shop has four full-time employees, including Jack, and does work on all three of the big diesel platforms, but Cummins work reigns supreme.

6.7L Cummins

“We have plenty of Fords and Chevys that come in, but we really specialize in the Dodge stuff,” he says. “If you see our parking lot and our customer base, it definitely shows. I’d say probably 75% of the stuff we work on is Dodge Cummins stuff. It’s what we like to do. It’s our niche and people see that.”

The shop does general maintenance and repair work, transmission work and high-performance jobs on occasion. Lately, the shop has even done work for a few fleet accounts, but general repair is CGT’s bread and butter. Any machine work CGT has to do gets sent out locally to Redwood Auto Machine.

While the original three members of CGT Diesel have gone their separate ways over the four years the shop has been in business, Jack has kept things going, and it means more now than ever after his friend Garrett Taylor passed away in 2020 due to an accident.

“People always ask me why I don’t change the name, but I’m keeping that name and keeping that memory alive and trying to make him proud,” Gulbrandsen says. “He was my best friend, so I’m striving to make this effort worth it and show him that we’re still rolling.”

One great example of the shop’s capabilities is a 2008 4-door short bed Dodge 3500 single wheel with a 6.7L Cummins under the hood. Jack built this truck up for use around the shop.

“We found this thing up in Oregon on Craigslist,” he says. “It had 120,000 miles on it, a clean title and all that stuff. It was $20,000. A buddy and I flew up there and drove it all the way back. It was bone stock when I got it.”

As you can expect, it didn’t stay stock for too long. Jack reached out to his buddy Adam Aquino at AA Motorworks and bought a 48RE core and went to town.

“It’s got a Suncoast triple disc, a Sonnax input shaft, a TCS intermediate, a TCS 29 spline output, GPZ clutches throughout, a PCS 2800 standalone controller, and a PCS valve body,” he says. “We went with a deep pan. I put a massive trans cooler where the spare tire is and ran all AN lines and I got some built trans tunes for it. The thing was just a blast to drive.”

However, the VGT turbo eventually broke and the truck was just a dog everywhere Jack went. He decided to use a T4 Steed Speed with an Infinite Performance 468 83/90 turbo with a Fleece second Gen swap kit, as well as a number of other upgrades.

“I’m running a Dynomite Diesel Products 12mm stroker injection pump,” he says. “I have DDP Super Mental 250% over injectors. I’ve got a FASS 290 and an Allied Diesel tank sump with return. I’m running a Fleece filter delete kit with a regulator. We’re running an S&S rail pressure sensor and relief valve, so we can run up to 30,000 psi rail.

“As far as valvetrain goes, it’s ARP head studs, Manton valve springs and pushrods, Manton corrected oiling trunnions, and Manton billet valve bridges. It’s running a Colt Stage 4 camshaft with their tappets. The pistons are just cut and coated OEM Cummins pistons. It’s using a stock crank. We haven’t really touched the bottom end and that’s kind of why I’m sticking with a single turbo for now. It’s going to spit out a rod if I do the compounds I’m thinking of.”

CGT Diesel also fabricated all the intercooler piping themselves, and it’s got a Turbosmart blowoff valve and wastegate set up on it.

“In addition, I have TIG-welded chromoly control arms, a transmission cross-member and an upper radiator pipe all from Adam Aquino,” he says. “We also relocated all the batteries to the toolbox in the bed, so all of the engine bay is cleaned up and we wired the whole truck with heavy-gauge wire. That cleaned it up a lot.”

The truck is lowered and sits on 22˝x12˝ American Force Jades. Jack says he’s hoping for high-800 to low-900 horsepower and around 1,300-1,400 ft.-lbs. of torque out of the 6.7L Cummins engine.

“I’m planning to use this as a daily driver,” he says. “I spec’d the turbo a little smaller so I can still tow my trailers around and do whatever I need to do. I’m sure we’ll hit the track with it a bit and see what it can do, but I just wanted a fun all-around truck.”

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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