Fastest 50: The Grand Canyon State’s Fastest Diesel Powered Machine

We set out to find the fastest diesel-powered machines in the country. We put a feeler out there searching for the fastest ever and the results are in. Now, we have already run into some controversy with the last state, but the update is pending. If you’re the fastest in your state, by all means, let us know. We will be happy to make an update. Now, let’s get to it. Which truck is the fastest in Arizona?

Well, like it or not, it’s another Cummins-powered Ram coined “The Warden”. The Warden is a build between two friends, Mark Rau and Fred Swanson, who’re co-owners together in their respected shop, FSR Diesel. FSR Diesel is an Arizona-based diesel performance shop specializing in all levels of the Dodge Ram 47RE, 48RE(RH) and 68RFE transmission. If you’re even remotely close to Phoenix, Arizona, or if you’re looking to just purchase your next transmission, be sure and check the guys at FSR Diesel out.

Although we’re looking for the fastest eighth-mile times, these guys originally built this truck hoping to bury it into the 8-second range in the quarter-mile. As a matter of fact, this was the first diesel truck in Arizona to break into the 8’s with an 8.97 pass at 158.8 MPH. Their goal was an eight-second pass and they conquered.

The Warden

The FSR Diesel-backed Ram was born in 2004 and was equipped with a standard cab long bed platform. Although it may look normal from the outside, this 3/4-ton Ram is nearly as modified as possible. It does look normal, but up close, you can tell something screams racecar. The 8.50-certified roll cage through the cab, the Lexan windows, and the fat drag tires on all four corners put off a fast vibe.

We spoke with Rau, Co-Owner of FSR Diesel, and pilot of The Warden, and he tells us that this truck was originally built for the Super Street class for the National Hot Rod Diesel Association events. With the, better known as the NHRDA, being no more, this gave the FSR-guys a reason to lighten the truck up. The Super Street class had a 6,000-pound minimum, therefore, it was heavy.

Thanks to The Brand Smith Co., "The Warden" is looking flashier than ever with this custom vinyl wrap.

With a truck this serious, you would think they would have gone to possibly aftermarket axles and adjustable suspension, but that isn’t the case. “After we have cut and trimmed The Warden down, we’re hoping to have it at a 5,000-pound race weight with me in it,” said Rau. “We haven’t yet tried different axles or back half. We want to see what we can do with factory axles and leaf springs.”

With that being said, there is more weight to be lost and even more elapsed time in the tank. The Warden’s best pass to date is 5.812 seconds at 128.3 MPH at 5,980 pounds. It does, in fact, require a ton of horsepower to make that much weight move that fast. In an attempt to lighten the load and hopefully not be so rough on parts and the fact that they don’t have a weight rule anymore, they have plenty more weight to trim.

“We have dynoed the engine and we’re happy with the results,” said Rau. “At Marlett Engines And Dyno in Indiana, our engine turned over 2,122 horsepower and 2,768 lb-ft of torque.” While these numbers tower over most, this was done with only #2 diesel fuel only. No assistance with nitrous oxide, but Rau tells us, they are spraying quite a bit these days.

With those kinds of numbers, you have to have good products on board. In fact, Rau credits a lot of his sponsors on board for helping get the truck where it is today. Done Right Diesel Performance, Dynomite Diesel Products, Diesel Performance Converters, and of course, FSR Diesel Inc.

So, what’s under the hood? The Warden homes a D & J Precision Machine deck plate Cummins powerplant with their beautiful billet timing case. All of the custom tuning that equalizes this power is credited to Ben Shadday at Done Right Diesel Performance, and the 2006 ECM is plumbed with a standalone harness.

With this timing case, it operates the twin gear driven CP3 high-pressure pumps.

For fuel, Rau relies on a pair of gear-driven S&S Diesel Motorsport 12-MM CP3 pumps, a PureFlow AirDog 260 4G lift pump, and a set of Dynomite Diesel Products Super Mental fuel injectors from their good friend Lenny Reed. With enough fuel for 2,000-plus horsepower, you need the matching air.

For air, this Cummins is plumbed with a pair of compound turbos consisting of an S483 and a 102-MM Garrett GT55. Supercooling this air is due to an HSP Diesel-built Air-to-Water Intercooler setup and works flawlessly.

Like I said earlier, FSR Diesel is known for transmissions. In fact, they wanted to prove their product. What better way to test your product then strapping it to the back of a 2,000 horsepower Cummins engine? The Warden uses a Stage 4 FSR Custom Trans equipped with reverse manual cope four-speed valve body and a Diesel Performance Converters quad disk torque converter.

Yes, it is cool to say you’re the fastest locally and it is even cooler to say you’re the fastest in your entire state. But, it simply isn’t enough for team FSR Diesel. In fact, Rau tells us they have had future plans for the truck and they are happening as we speak. Losing the steel hood, fenders, and bedsides, they are going to a full fiberglass body. They have that 5,000-pound goal in mind and with their power, that Arizona record is no longer safe.

As you can see, there is plenty of weight to be lost. What will be next for The Warden?

If you’re serious about going fast, maybe you should chat with Rau and his crew. We can’t wait to see what The Warden has in the tank in the very near future and look forward to updating Arizona’s fastest diesel time. If you think you’re the fastest in your state, let us know. We’ll be glad to run the numbers. For the latest in diesel motorsports, stay tuned to Diesel Army.

About the author

Artie Maupin

Artie Maupin is from Southeast Missouri and has an extreme passion for anything diesel. He loves drag racing of all kinds, as well as sled pulling competitions.
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