RPM Motorsports’ Russ Wullenwaber

RPM Motorsports’ Russ Wullenwaber dyno tested his 2020 GMC AT4 3500 Duramax last week. The Northern California racecar driver recently traded in his 2017 Banks Derringer-equipped Duramax for a 2020. Shortly after picking up the AT4, Russ ordered a Derringer inline tuner for the new truck in hopes of giving it even more towing power. The truck is a daily driver and hauls Russ’s beautiful 29,500-lb, 46-ft race trailer with his drag race cars inside. It has a lift to load up both cars, living quarters and to add to all that weight… a Smart car tags along behind it.

Russ has two race cars: a blue Nova with a 598-cubic-inch nitrous motor, and a black Duramax LBZ diesel-powered Nova. That one was tri-turboed with three S475 turbos on it. Unfortunately, the diesel-powered Nova has been out of commission for a while due to a mishap that saw Russ putting it over the wall at a Sacramento track just after the quarter-mile at around 130 mph. “It did three wheelies on us: about a 100 ft out, about 500 ft out and another one at about 1,000-ft out. At the last wheelie, it went left on me, I pulled the chute, then swung right and over the wall!” Russ is fine, and after quite a while the black Nova is just about race-ready again. “We’re going to run the first with a very large ProCharger and nitrous, then we may run a super turbo configuration.”

Russ received his Banks Derringer tuner with iDash at the beginning of the week and installed it almost immediately. He strapped the AT4 to the Dyno at Zmod Motorsports in Rancho Cordova, CA. He wanted to see how close the numbers were to Banks advertised numbers before hitting the track to see what the ET/MPH improvement was overstock. Seeing that a dyno is a tool, and knowing that numbers differ from dyno to dyno, he’d compare his bone stock HP pull to the Derringer level 6 pull. And, he’d stick with uncorrected numbers. Whatever the truck made at the altitude is what it made. “We wanted to get legitimate numbers,” Russ explained, “and at first we were getting numbers on runs that wouldn’t repeat… until the truck was warmed up. Then we were able to do multiple runs where they all pretty much matched each other.” At the end of many runs Russ’ 2020 Duramax L5P picked up a consistent 89-hp, 8-hp more than advertised. “The Derringer took literally 30 minutes to install,” says Russ. “It was actually even easier to install on this one than on my 2017 and went on in a snap. All in all, great product, great quality, real-world advertised numbers, and zero smoke.”

So, what’s next for Russ and his testing? “Prior to this truck I took my 2017 out to the strip and ran it multiple times with the Derringer in stock all the way to level 6, and we go some great results. I’m going to take this new truck and do the same, and I’ll share with you guts what it does.”

We’re looking forward to your results, Russ!