Supercharged Diesels: A New Twist On An Old Trick

• May 29, 2022
• Story By
  Mike McGlothlin

It should’ve been a sign of things to come when Wagler Competition Products brought its “shop truck” to the 2017 Ultimate Callout Challenge. The engine, which appeared to be climbing out of the Chevrolet Silverado’s engine bay, was both supercharged and flaunting two turbochargers. Not much time passed before the turbos disappeared and only the blower remained in this particular engine program. A few years later, something similar happened 2,000 miles away in Azusa, California, where Banks Power embarked on a captivating screw-blown, nitrous-huffing, diesel-powered Chevy C20 project intended to tear up the street.

No, they’re not screamin’ Jimmy Detroits. They’re modern age Duramax diesels with screw blowers feeding them—and they’re changing the way many think about high performance oil burners. Instant boost right off idle, huge boost up top and stupid fast engine speed (for a diesel) are just a few of the highlights. And think Top Fuel Dragster-like decibels when you catch one in person… From the trend-setting “Screwed Coupe” to Wagler’s 4-second eighth-mile rail to a Pro Mod Corvette that’s yet to debut and Banks’ high-profile street terror, something new is brewing in the diesel world—and it’s showing tremendous potential.

The Screwed Coupe: A Sign Of Things To Come

One of the first indications that a blown Duramax trend was on the horizon came from a company named Wagler Competition Products. The Odon, Indiana place of business has been offering aftermarket support for GM’s 6.6L diesel V-8 since 2011 and it’s the go-to place for performance cylinder heads, connecting rods, camshafts and complete engine builds. Most saw this ’37 Chevy Coupe for the first time at the 2017 SEMA Show, where it was quickly discovered that the hulking PSI screw blower was the only source of forced induction. Under the blower sat a DX500L Duramax engine, an all-aluminum Wagler creation sporting some of the strongest and most avant-garde parts in the industry.

Screw-Blown Rail

Boasting a massive, custom-built PSI blower, the folks at Wagler put this dragster into circulation in 2020. Literally blasting onto the racing scene, it immediately went low 4’s in the eighth-mile. Within a few short months the rail—which had made a best pass of 4.23 at 166 mph—was already within striking distance of the quickest diesel vehicles in existence. Breakneck, 1.07-second 60-foots were also being pulled off. Unfortunately, before any of the issues that were holding the dragster back could be ironed out a chain reaction of undesirable events landed it in a mangled mess at the end of the track.

It’s A Diesel, We Promise!

Nestled within the Wagler rail’s chassis sat a 385 ci Duramax. Eight high-flow S&S Diesel Motorsport injectors protruded through the billet valve covers and a pair of S&S CP3’s maintained rail pressure. Then there was the dominant PSI blower up top. Driven to the tune of producing between 40 and 75 psi of boost, a blower requires different needs than a turbocharger living in the same environment. To keep the supercharger running cool, a 50/50 mixture of water-methanol was used, and was distributed courtesy of four Billet Atomizer injectors. To ensure intake temps remained in check (along with the added benefit of providing extra ponies), nitrous oxide was employed. A Motec ECM controlled both the engine and the water-methanol system, while a Coan Engineering Powerglide transmission sent power to the dragster’s rear end.

The Loudest Dyno Cell In Diesel

But just because the rail was wrecked it didn’t mean Wagler had given up on the blown Duramax platform. On the contrary, the blown Duramax arrangement piqued enough interest that another heavy hitter in the diesel racing world wants to give the combination a try. More on that below. Right now, there is likely a supercharged, water-methanol cooled and nitrous-fed Duramax bolted to the Wagler’s engine dyno. There, in one of the loudest rooms in diesel, they are likely finding even more horsepower to play with.

7,500 RPM!

It’ll be engine number 2 for the vehicle it gets dropped into, but the second time should be a charm. The car? How about a C7 Corvette body sitting on a Jerry Bickel chassis—and a curb weight less than 2,700 pounds! Wagler will supply the power plant, a billet-aluminum DX series Duramax assembled with top-quality ARP fasteners, fueled by S&S and tuned by Hardway Performance by way of a Motec ECM. And although it’s not pictured above, the exotic Duramax will be topped off with a massive PSI blower. During engine dyno testing, it’s rumored that the all-billet V-8 turned an insane 7,500 rpm. When it’s finally unveiled at the track, look for the team behind it to shoot for 3-second eighth-miles.

Banks’ Blown L5P (Available As A Crate Engine…)

As a rolling advertisement for its new line of L5P Duramax crate engine packages, Banks Power decided to build a supercharged and nitrous-fed custom ’66 Chevy C20 tire-melter to get everyone’s attention. A Roadster Shop chassis, custom 9-inch Strange rear-end, Ridetech air-ride and an over-the-top tilt-bed system all play second fiddle to the ultimate piece of eye candy lurking under the truck’s Patina’d hood: the R866SC Duramax. Unlike Banks’ other variations of L5P crate options, which feature twin-turbocharging or turbocharging and supercharging combined, this baby packs a single Whipple supercharger.

Billet Whipple

At the heart of the R866SC Duramax engine package is this twin-screw blower from Whipple. Specifically, Banks worked with Whipple to make the company’s 3.8L Gen V supercharger work on the Duramax application. The Whipple is driven via a fluid-filled race viscous damper developed in-house at Banks and utilizes a 12-rib belt rather than a Cog style one. An engine-coupled air-to-water intercooler keeps intake temps on ice (and enjoys its own coolant circuit) and a unique NOS nitrous system adds an extra hit of horsepower. The engine takes its cues from a Motec ECM.

A One-Of-A-Kind, Classic Diesel Repower

With a few tweaks in the Motec software and the nitrous bottles warmed up, anywhere from 700 hp to 1,200 hp is said to be on the table for LokJaw. And if we know anything about superchargers, it’s that with instant boost you get instant torque—so needless to say the Nitto Invo ultra high performance tires have their work cut out for them. On the street, Banks’ ’66 C20 will be a handful, to say the least. And not unlike the other blown Duramax V-8’s in this piece, its exhaust note will provide a commanding presence no matter the setting.