A few months ago, we linked up with Pusher Intakes to see what was coming available on the market that would interest our readers. This included their 2017-and-up Ford Power Stroke Intake Systems that we installed on a local ’17 F-250. The improvements were impressive, but during that conversation, we heard about another upgrade to help this truck breathe better. So, right after we finished the intake system install, we started testing the new compound turbo for ‘17-and-up Power Stroke engines.

With a compound turbo system, an additional turbocharger is added to feed air into the stock turbocharger. The advantages of a compound turbo system include lower exhaust gas temperatures (EGT), quicker spool-up time, reduced turbo lag, and improved efficiency, all of which result in a better driving and towing experience.

When it comes to ordering this kit, you have plenty of options. To start with, you can choose from different size turbochargers and you can choose your powder-coated color based on your tastes. For this kit, we decided to go with an S475 turbo in the Titanium finish.

“I wanted a neutral accent under the hood and the Titanium color looked just right,” said Andrew Clark, the truck’s owner. “Although Pusher offers many different sizes, they recommended the S475 because it complements my current modification list the best. For what I do with the truck, we’re looking for a great towing/everyday driving setup.”

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As expected, the quality of packaging, the design and fabrication of the parts, and the attention to detail of the finish is second to none.

The Compound Turbo: How It’s Done

Excited to start the installation, we headed over to C & B Diesel in Jackson, Missouri where they were kind enough to allow us to use a truck bay for the day. When speaking with Pusher about this system, we learned that the installation process was going to be a little different than anything else on the market for these 6.7-liter-equipped Fords.

“The space constraints under the hoods of these trucks are really tight to easily package a compound turbo system,” stated Jacob Allenbaugh, owner of Pusher Intakes. “That is the reason for the decision to replace the factory passenger-side battery and low-pressure A/C line. We needed to make ample room for the additional turbo and its required piping.”

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We started by safely evacuating the air conditioning system and disconnecting both of the truck’s batteries. Since this truck previously had the Pusher Intake System, we removed the cold air intake and the airbox as well.

After those items were removed, we removed the passenger side battery, battery tray, battery tray support bracket, and the inner fender. Next, we loosened the nut on the air conditioning lines at the evaporator connection on the firewall. The factory low-pressure line will be removed at the firewall and replaced with the one supplied by Pusher.

The disassembly continued with the removal of the cold-side charge tube from both the intercooler and the intake manifold. With these parts removed, Pusher instructed that we now replace that low-pressure air conditioning line with the supplied new one. With the new line, you will need to carefully bend the high-pressure line to match.

Next, we separated the downpipe from the existing exhaust under the truck. When it came time to disconnect the topside of the downpipe, we fought with the factory connection. Pry bars, hammers, and a few choice words later, we finally managed to get the clamp off and finished removing the downpipe.

Using the supplied hose from Pusher, we made the new connection. Once that was done, we modified and rerouted the injector harness on the passenger side of the engine. With all that reconfigured, we were then able to install our compound-turbocharger mount by removing and reusing five existing valve cover bolts and adding one Pusher-supplied bolt. But before we could install our additional turbo under the hood, we made our way under the truck to install Pusher’s oil drain for the new turbo.

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Installing the support bracket (pedestal) for the additional turbo.

Pusher’s mounting location prevents the pooling of the turbo’s return oil through its higher mounting location. The drain fitting’s location is above the normal oil level which allows the oil to freely drain into the pan without obstruction. To make this connection, we had to grind the webbing on the case and mark the location of where we would drill and tap.

Removal of the lower engine oil pan before drilling is a must. You do not want debris from drilling and tapping in the bottom of the pan. Once it was drilled and tapped, we replaced the pan onto the engine. With the adapter installed, we could make the drain tube connection between the pan and the turbo pedestal.

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In the first picture, you can clearly see where we've ground down the webbing of the pan to make room for our hole (left). In the right photo, you can see the hole is drilled and ready to be tapped.

We were finally able to install the additional turbocharger to its new home on the pedestal. We loosely fastened it and made our oil feed connection. We removed the factory pipe coming from the passenger-side cylinder head to the factory turbo, to make for an easy installation of our new intermediate exhaust pipe.

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With the additional turbo mounted, the exhaust plumbing was routed.

With the V-band connections at the factory turbo and the new turbo loosely fastened, we then reinstalled the factory pipe. When all piping was in place, we tightened the remaining connections in the sequence recommended by Pusher. After the intermediate pipe was tight, we then installed the new two-piece downpipe from the turbo to the existing exhaust.

After a quick clearance check of the new exhaust piping, we added a few zip ties to hold some of the wiring harness for extra clearance. Since this turbo system’s placement of the new atmospheric turbo is directly where the factory airbox once was, we took the provided battery tray and battery and attached them to the fender support structure.

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Since the OE battery and battery tray are in the way, a new supplied tray and battery can now be installed.

With the new, smaller battery secure, we made our power and ground connections. The provided battery is smaller in physical size but provides more power than the physically larger battery it is replacing. We then reinstalled the Pusher intake manifold and secured the transmission dipstick.

To connect the factory turbo to the new compound turbo on the cold side charge tube, we used the provided 4-inch to 3-1/2-inch coupler and its 4-inch T-bolt clamp. Since the intermediate charge pipe uses a V-band connection, we installed the rubber O-ring before mating the turbos. Next, we reconnected the intercooler to the intake manifold using the existing hardware.

To finish this project, all that remained was the installation of the 90-degree intake tube, the new air filter, and the reinstallation of the mass-airflow sensor onto the front side of the new turbocharger. After we checked all of our connections, we refilled the coolant system and filled the engine with oil for our first start. Once the truck was running, we checked everywhere for leaks to make sure all was good.

Driving Impressions 

Clark and I both own and have experience driving trucks with compound turbo systems, but we weren’t sure what to expect compared to our Cummins-powered machines. However, we were intrigued by knowing how great the Rams react to more air. In fact, I used Pusher’s Cummins compound turbo system on my truck and I couldn’t be happier.

After the installation, we immediately hit the road to check for leaks and get a feel for how the upgrade performs. Clark’s initial thoughts, after the smile wore off his face, were good ones. “So far, I am beyond happy with how the truck is reacting to its new parts. Just in the first few miles, I can tell that the truck pulls way harder,” he said. “The whistle that the atmospheric turbo makes is music to my ears.”

After a few weeks of driving, Clark has noted nothing but good results, even after several hundred miles of driving. This system exceeded our expectations and Pusher continues to raise the bar. Clark is noticing improved fuel mileage, lower exhaust temperatures, and a better overall driving experience — just as advertised.

If you have a diesel truck and you’re looking to improve its efficiency, look no further than Pusher Intakes. To find out what they offer and what fits your ride, be sure and check out the website here. For more parts reviews, installs, truck features, and event coverage, stay tuned right here at Diesel Army.