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Little Giant: SDP’s Compound Turbos Make Loads of Power While Lowering EGTs

Boosted Babymax

Brian Lohnes
Oct 12, 2017
Photographers: KJ Jones
Large-displacement I-6 and V-8 engines have dominated the world of diesel performance in North America since the late 1980s. But with the always-changing socio-environmental climate, business economy, and automakers’ move toward globalizing things like engine and chassis platforms, we believe there will be more and more small-displacement turbodiesel engines infiltrating the U.S. market in the coming years.
Smart aftermarket companies recognize this and are developing parts and components to increase both the performance and the working ability of these small-displacement engines. Screamin’ Diesel Performance (SDP) in Port Angeles, Washington, has long established itself as a leading name in Duramax performance through an extensive line of products tailored to the venerable 6.6L platform that has been GM’s diesel calling card for more than a decade now.
With the introduction of the 2.8L Duramax LWN engine in the ’16 Chevrolet Colorado and GMC Canyon, SDP now has products to enhance the power levels of these little engines reliably. Let’s find out how and why SDP decided to take the bull by the horns on this relatively new-to-the-domestic-market engine.
When we caught up with SDP’s owner, Scott Helpenstell, our first question was the most obvious one: After so many years of work with the V-8 Duramax, why go off the reservation with this new engine? “For eight years, we have been doing compounds on fullsize trucks,” Scott says. “This new engine really got me interested in trying something new. We are a Duramax-only shop, and the idea of working with these engines makes sense on that front, plus there are mechanical similarities between the two that we think we can work with.” The biggest similarity is in the fuel system. “These 2.8L engines use a common-rail system that is very close to the setup used on a 6.6L Duramax LP5,” Scott says. “The injection pump is nearly the same, there are Denso injectors, and it is a good platform on which to build a unique, refined package.” Scott ordered a truck as soon as the diesel option became available, and as soon as he got it back to the shop and ran it on the dyno in stock form, work began on developing the compound-turbocharger kit.
Photo 2/22   |   Here’s the rather crowded engine bay in Micah Thomas’ 2.8L Duramax-powered ’16 Chevrolet Colorado. It’s hard to look at this and think there’s a way to add another turbocharger in here!
Unlike their fullsize Chevrolet and GMC brethren, the Colorado and Canyon do not have a lot of extra space in their tightly packed engine bays to easily add a second turbocharger to the engine. Packaging the kit in a professional and clean manner became a primary focus once work got under way. “Initially, this was a big challenge,” Scott says. “Having never seen one of these trucks before, I opened the hood and got my wheels turning on how we were going to make it all work. Where does everything need to go and how do we get it to go there?”
SDP started by eliminating the factory airbox and making the critical decision to relocate the factory coolant tank to the firewall using a tank designed and manufactured in-house. “Doing those things freed up a lot of space to locate the turbocharger and the downpipe. The next step was coming up with a good mounting solution for the turbo itself, and that took some time. We ended up developing a mounting system that uses the exhaust manifold, and it’s very rigid. We came up with some very intricate brackets, and it proved to be one of the biggest challenges of the whole build. We refused to do anything halfway, so we took the time to do it right,” Scott says. Getting oil to the turbo was another large obstacle that was overcome. “What makes it difficult is the fact that there are no ports to tap into on the passenger side of the engine, so we developed a custom banjo fitting to work with the pressure sensor that delivers the oil.”
Increasing an engine’s power output, especially using the stock internals, is an exercise in restraint to some degree. Scott explains, “When we had the first system installed two weeks after getting the truck, we went to work with our tuning partner Aaron Wiebe at All-In Truck Performance. Almost immediately, we saw a jump from 160 hp to 260 hp at the rear wheels.” Aaron uses EFILive tuning software and advanced techniques like monitoring individual cylinder pressure to learn what’s actually going on inside the engine. “Our kits will make a reliable 260 hp,” Scott says. “We believe that is about the limit of the factory connecting rods. For a truck someone is going to use and drive daily, tow with, and so on, this is a 100hp performance increase that changes the whole dynamic of the truck in a positive way.” If a customer wants a more maximum-effort attack, SDP can help, but only if the engine is updated with the custom Carrillo connecting rods made specifically for this specific compound-turbo application. “The reality is that for the long haul, the stock connecting rods do not have the strength to stand up to more boost than the amount our basic system produces,” Scott says.
Photo 3/22   |   Removing the factory air-intake system clarifies the viewpoint significantly. One of the things we noted is the fact that there doesn’t appear to be any good place to actually mount a second turbocharger.
Keeping the original turbocharger (as opposed to simply sticking a bigger turbo on the engine and calling it a day) as part of the package and maintaining the truck’s good manners on the street is paramount. “Some of the ideas we had going in about what would work best proved to be untrue,” Scott says. “We went through various housing and wheel designs, even different frame sizes. Some turbos we believed would work the best had higher drive pressures than we want to see, and that’s how we ended up with the BorgWarner S300 SX-E turbo feeding the factory variable-geometry unit.” That particular turbocharger is the best component for the package. It delivers great driveability and lower EGT under heavy throttle conditions than the single stock turbo. “When you tip into the throttle, there is a little more acceleration than stock. But when you get into the pedal, the difference is dramatic,” Scott says. “The torque comes on very quick, and there is lots more power up top, in the rpm range where the truck would struggle before.” Scott tells us that when testing the truck’s 7,700-pound towing capacity, the additional power makes the difference between a truck that is at maximum effort to keep up and one that is very comfortable with the load.
The 2.8L Duramax compound kit (while formally a compound setup, SDP refers to its turbo systems as “twins”) includes every component, nut, bolt, clamp, and accessory necessary to bolt it to the Duramax-powered ’16-to-present Colorado or Canyon. “If a person is comfortable with removing a transmission or doing work like swapping injectors, they can handle this job,” Scott explains. “I would budget about a weekend’s worth of time to complete the job. Realistically, if someone with some experience with a wrench started this job on a Friday night, they could be driving the truck to work on Monday morning. The only thing that may intimidate some people is drilling and tapping the oil pan for the oil-drain line, but if you take your time and don’t rush the job, it is not overly difficult.”
While we’re not really used to seeing small-displacement turbodiesel engines in trucks here in the U.S., we believe they will be here for a long time. We think it is cool that companies like SDP are creating performance options for the 2.8L Duramax, and this system could very well be the right one for the Baby Duramax in your ’16-to-’17 Chevrolet Colorado or GMC Canyon.
Photo 4/22   |   The stock variable-geometry turbo serves its purpose dutifully under normal conditions, but when the workload gets heavy or thoughts turn to performance, Screamin’ Diesel Performance of Port Angeles, Washington, has created a compound-turbo system to give it some help.
Photo 5/22   |   SDP’s owner Scott Helpenstell relocates coolant lines in the engine bay. Moving lines, the tank, and some items under the hood is key to making this setup work.
Photo 6/22   |   This is the custom-designed banjo fitting that seats beneath the oil-pressure sensor on the block. This banjo fitting is the lynchpin in making sure the turbocharger has a good oil source, as there are no ports on the passenger side of the block.
Photo 7/22   |   SDP fabricates and tests the TIG-welded coolant tanks in-house.
Photo 8/22   |   Scott says there is one part of the installation process that may intimidate some people, and that is drilling the block for the oil-drain line from the turbocharger. As long as the installer does not rush the job, there’s nothing to fear.
Photo 9/22   |   Here’s the finished oil-drain line at the back of the block, complete with a threaded fitting and high-quality braided line.
Photo 10/22   |   SDPs Compound Turbos Kit
Everything one needs to install this system successfully is included:
BorgWarner S300SX-E turbo (with race cover)
CNC-machined flanges TIG-welded to the plumbing
CNC-machined/tapped and laser-cut turbo mount
Powdercoated (any color) cold-side plumbing
Cerakote Glacier–coated hot-side plumbing
Heat wrap
All sensor mounts TIG-welded in place
Oil-feed and drain lines with Vibrant AN fittings
Dry air filter
Custom coolant expansion tank
Stainless steel clamps and high-quality silicone boots
1/8-inch NPT ports for boost-pressure gauge, wastegate lines, injectables, and such
All necessary bolts, nuts, gaskets and clamps.
Photo 11/22   |   The kit ships with a BorgWarner S300SX-E turbocharger. While this one is powdercoated blue, almost any color imaginable can be created for the turbo and tubing.
Photo 12/22   |   Check out the flange thickness on this pipe. Thick flanges are a good indicator of the strength of this system. They ensure even clamping and resistance to flexing and deflecting.
Photo 13/22   |   Scott completes some of the preinstallation work.
Photo 14/22   |   It may not look like much installed, but this bracket is something Scott and the SDP crew are very proud of. Why? In many ways, this turbo-mounting bracket is the most important part of the system, as it is subjected to incredible load and stress from the engine.
Photo 15/22   |   Old hot-rodders used to say, “Chrome don’t make it go.” But in this case, the SDP 2.8L Duramax compound-turbo system looks like a million bucks and it supports significant power.
Photo 16/22   |   Scott attaches the drain line to the bottom of the turbocharger before installing it on the engine. Setups like this include detailed instructions for a good reason.
Photo 17/22   |   Displacing only 2.8L, the little Duramax makes respectable power in bone-stock trim. But, as we get closer to completing the installation, we can’t wait to see what, if any, the improvements are when we’re done.
Photo 18/22   |   With all the major work completed and the kit 90 percent installed, this photo provides you with an idea of how the layout works. We cannot get over how well this system is packaged.
Photo 19/22   |   SDP offers optional equipment such as 40mm Turbosmart wastegates.
Photo 20/22   |   With the compound-turbo system fully installed and the engine cover back on, everything looks great in blue powdercoat. If you’re really sneaky, have it done in black, and some diesel enthusiasts might miss the fact that you’ve bolted another turbo on your little rig’s engine!
Photo 21/22   |   After completing the installation, we took the truck for a drive. What a difference 100 more horses make on the 2.8L Duramax! The truck is like a completely different animal! The driving manners are factory-perfect, the EGT stayed happy the entire time we were cruising, and we’re now completely addicted to the additional power and torque.
Photo 22/22   |   The dyno sheet shows the massive increases in horsepower and torque over stock. It’s important to note that the very impressive numbers we saw (305.12 hp/543.81 lb-ft) are 100 percent valid. The gains are pretty much beyond the threshold of performance the 2.8L Duramax engine’s stock connecting rods can support for any significant amount of time. The 295.34/503.62 was achieved with a 100hp tune. While custom ECM calibrations are optional (and require engines upgraded with Carrillo rods), the base 2.8L Duramax compound-turbo kit is shipped with All-In Truck Performance’s tune that yields about 260 hp, a calibration that’s adequate for daily driving and towing, which safeguards your engine’s internals.

Sources

Screamin' Diesel Performance
360-417-9000
www.sdptwins.com
All-In Truck Performance
432-209-7095
allintrucks.com

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