Ever wondered what goes into making high performance diesel engines? We sat down with our very own Steve O'Neal, a true veteran in the diesel performance world, for an in depth conversation that covers everything from the adrenaline rush of being at the race track, to the details of designing a turbo. This isn't your normal “tech talk”, it's a behind the scenes look at the passion, innovation, and hard work that goes into making performance parts that power record breaking (and insanely fast) diesel engines. 

Steve's Journey with Stainless Diesel

Let’s start at the beginning… Steve's history with Stainless Diesel is an interesting story. He officially became an employee in 2021, but his relationship with the Stainless Diesel dates back to nearly a decade... from running around with us at the track and even being part of the pit crew while Johnny competed in Pro Street. Before coming on board as an “official” employee. Steve ran his own shop for over a decade, heavily utilizing Stainless Diesel products and contributing his knowledge to our research and development program. Having a chassis dyno of his own allowed Steve to perform crucial R&D on some of Stainless Diesel's newer products.

The Unforgettable 2020 Race Season

The conversation quickly turned to the legendary 2020 race season, a year Steve remembers fondly. "That was a year, dude. We had the time of our lives," he said. Our team built meaningful relationships and had a truck that was absolutely dominating. All of this combined with the team’s energy really made 2020 a special time for Steve. One race really stands out to him in particular. While at a race in Florida, the crew spent the day having fun instead of working. Between grabbing ice cream and floating around the lazy river, they were having a blast. Yet, despite “goofing off” all day, the truck was ready and ultimately performed flawlessly. The hard work had paid off and was obvious to everyone at the track. We were having great success on and off the track. 

Steve also admits to bringing a unique vibe to our team… including smack talking and getting people fired up. If you know Steve, I am sure this doesn't surprise you though.

Innovating Under Pressure

The race truck was a beautiful example of engineering, often pushed to its limits. During a Virginia race event, the team encountered transmission issues and other design failures. Steve vividly recalled changing the nitrous setup. At that time nobody was using that much nitrous in diesels.  We pushed the components to the breaking point. The truck's computer system was incredibly complex, which basically required an engineering degree just to understand.  Johnny's goal was to use more horsepower than we have to and leverage traction control. However, it was going to take four years to even figure that out. We came up with a solution… It was VERY ugly looking, but it worked well! Interestingly enough the more we abused the truck, the better it performed. 

From Race Track to Daily Driver: Evolution of Stainless Diesel

Stainless Diesel has evolved significantly from our early racing days. While R&D for race turbos remains crucial, the company now heavily invests in products for daily drivers. A challenge Steve embraced. 

The experiences we gained from the race track contributed to our R&D program. Our tech department at Stainless Diesel is highly skilled at guiding customers through various different issues, many of which we have experienced first hand with our own race truck. Those experiences have allowed us to be able to give knowledgeable technical support and ultimately solutions. 

The team at Stainless Diesel has also grown, with key players like Nick (known for his glorious head of hair, Ben Junior  and Eric, who has been doing fab work for many years. This dynamic team is constantly changing and evolving.

The Truth About Boost Gauges

Steve strongly suggests anyone running a performance turbo to invest in an accurate boost gauge. He warns against relying solely on OBD2 monitors. A monitor might show 35 pounds of boost, but the turbo could actually be making more than that  without you seeing it.

For accurate readings, Steve recommends a standalone transducer, like those made by Edge, which can read up to 100 PSI. These integrate easily and provide raw, un-capped data, unlike most OBD2 displays.

Turbocharger 101: Understanding the Basics

For those new to the turbo world, Steve provides a clear breakdown of basic terminology:

• Blue Side/Cold Side (Compressor): This is where fresh air is taken and compressed. It has an inducer (small side where air enters) and an exducer (big side where air exits).

• Hot Side/Exhaust Side (Turbine): This is driven by exhaust gases. It has an inducer (big side where exhaust enters) and an exducer (small side where exhaust exits).

Both wheels are connected by the same shaft. Exhaust energy spins the turbine, which in turn spins the compressor, creating boost.

Oil Feed, Drain, and the Bucket Analogy

Proper oiling is crucial for turbo longevity. For journal bearing turbos, Steve recommends a -6 oil line. The drain is equally, if not more, important. You can definitely overfeed it but you can’t over drain it.

He used this analogy to explain: "If I was pouring two gallons in at a time, but I could only take a gallon out... eventually the bucket's gonna overflow". This overflow leads to oil leaks from the front or rear of the turbo. He mentions that while a -10 drain hose might sound large, the internal diameter of the fittings can be as small as 0.400 inches, far smaller than the 7/8-inch ID of older factory drains. A minimum of 0.625 inches ID is recommended for drains.

Nine Blade vs. Ten Blade: The Turbo Debate

A popular topic on social media, the choice between a nine blade and ten blade turbo always sparks a lively debate. Steve explained that there are a lot of advantages and disadvantages to both options. What works for one setup might not for another.  

VGT: Old Tech, New Tricks?

VGT (Variable Geometry Turbo) might seem like cutting edge technology, but Steve considers it old technology at this point, as the first light duty diesel VGT emerged over 20 years ago.

The purpose of VGT is to dynamically change the surface area of the housing. This allows the turbo to act like a small housing at low RPM for better "tip in" and drivability, then open up to a large housing at higher RPM, letting the engine breathe and make power.. This transition from small housing to a big housing gives daily drivers both low end responsiveness and top-end horsepower.

The Drawbacks of Variable Turbos

Despite their benefits, VGTs have their downsides too. They are subject to carbon buildup and their moving components cannot be oiled or lubed. Steve noted that an old six liter VGT turbo would seize if left sitting due to rust on the veins and unison ring. Many enthusiasts chose fixed vane turbos to avoid these issues, but Steve found that going back to variable turbos after extensive testing yielded impressive results. His own six liter Excursion, with a 6674 T483 variable turbo, made 650 horsepower and 40 pounds of boost without a tune change, and no longer drives like a turd (Steve’s word choice).  

Steve's insights highlight the fascinating blend of engineering, experience, and a bit of personality that defines the world of diesel performance. From the meticulous R&D at Stainless Diesel to the practical advice on boost gauges and turbo components, we hope this blog offers valuable knowledge for both seasoned enthusiasts and curious newcomers.