It’s really no secret that a clean and complete burn during the combustion process is the ticket to improved performance and on-track consistency. Over the years, racing fuel companies have invested considerably into the development of blends of fuels that deliver such an ideal burn in the cylinders of high performance racing engines, and racers are the benefactors of this research. Among those has been Renegade Racing Fuels, a Kentucky-based brand that has quickly established itself in the drag racing marketplace; Renegade’s engineers have taken a scientific philosophy to how they approach the development and testing of their range of fuels, known as Quantum Phase Technology.
“Our Quantum Phase Technology was founded through the study of quantum physics,” Renegades’s Ron Finney explains. “Quantum mechanics informs us that there are certain properties or particles in a material that can’t be known exactly. In large quantities, general principles apply and kind of match up with general theory on physics, but when we start really drilling down into the quantum world, to the atomic level, we start finding things that don’t always react predictably and other outcomes can be known. We use this thought-process to say, racing fuels came from taking avgas and xylene and toluene and mixing all the common stuff and it kind of developed from there, so we took a look at it and said if we’re going to be a market leader, we had to do something else if we were going to arrive at a different outcome. We took a look at the processes and worked to create a better outcome than what is currently on the market — bucking conventional theory, if you will.”
The result for Renegade has been a lineup of cool and clean-burning fuels that’s proven to be consistent on the racetrack, where it really matters.
Everyone thinks higher octane fuel burns slower, but it doesn’t. With a racing engine, you’re turning it faster, and that means the piston is there at top-dead-center for less time, so the last thing you would do is slow down the burn rate of the fuel — you have to accelerate it. – Ron Finney
“When you go back to the age-old ways of tuning, guys say to throw fuel at it until the exhaust turns black, and then back it off until it lightens up and gets that light gray color. Our fuels are going to burn to the point that they don’t burn, so we tell racers not to try to apply that same approach and turn the plug black, because our fuel is going to burn, it’s going to burn, it’s going to burn to the point that it doesn’t burn. At that point you’ve thrown so much fuel at it that you’re going to drown the plug,” Finney explains.
Renegade notes that its fuels generally don’t blacken the ports, instead leaving more of a gray residue — this is the optimal place to be, because signs of black matter on the ports and plugs are proof-positive you’ve put too much fuel to the cylinder; the black residue a result of unburnt fuel during combustion. Finney provides a unique analogy to illustrate this.
“If you’ve ever seen a house that’s half burnt, what does the wood look like?” Finney asks. “It’s charred black. Now, consider a campfire; you have a fire and you wake up the next morning, it’s totally burnt out, what color is the ash? It’s a white or a light grey, and that’s because everything is gone. That’s complete combustion, and it doesn’t matter if you’re burning wood or you’re burning fuel. If you have a light grey exhaust, that’s proving that you’re burning all of the fuel, you’re not throwing half of it unburnt out of the port.”
According to Finney, this combination of both a cooler and cleaner burn is what results in greater consistency, which is huge for bracket racers in particular, but likewise beneficial to heads-up competitors who require consistency and repeatability in their tune-up.
Renegade’s blends are designed with the intent of producing a fuel that responds to the combustion pressures and temperatures, will fully combust, and do it quickly enough to keep up with the high-rpm demands of a racing engine. In a high-speed engine, you have to accelerate the burn rate of the fuel, rather than slow it down. Finney notes this concept as it relates to octane rating is a common misconception.
“Everyone thinks higher octane fuel burns slower, but it doesn’t. With a racing engine, you’re turning it faster, and that means the piston is there at top-dead-center for less time, so the last thing you would do is slow down the burn rate of the fuel — you have to accelerate it. But it has to be a precise acceleration to match the engine. That’s why there are so many different blends of fuel: to match the cylinder pressures, the engine rpm, and so on. We want to match the burn rate to the application.”
Burn rate, as the name implies, is the rate at which the fuel burns. Again, we don’t want a slow-burning fuel in a race engine. Maximum cylinder pressure occurs at around 20 degrees after top-dead-center and beyond this point, additional fuel will not result in increased cylinder pressure. As Renegade eloquently puts it: If fuels burn too slow or too late they will make great fire shows out of the pipes, but won’t be fast on the track. The fuel needs to burn in the combustion chamber to create the hot expanding gas to push the piston down and drive the crankshaft.
Our fuels are going to burn to the point that they don’t burn, so we tell racers not to try to apply that same approach and turn the plug black, because our fuel is going to burn, it’s going to burn, it’s going to burn to the point that it doesn’t burn. At that point you’ve thrown so much fuel at it that you’re going to drown the plug. – Ron Finney
Octane, meanwhile, is simply a fuel’s resistance to detonation — Renegade notes that engine knock is the result of fuel molecules breaking apart and detonating before the flame front in the combustion chamber reaches them. From this, an engine will both fail to produce peak power, and could perhaps be damaged by the shockwaves from this detonation. The octane ratings you’re familiar with at gas pumps and on fuel cans are referred to as the anti-knock index and calculated on a formula of R+M/2 (or Research Octane + Motor Octane/2 = Pump Octane)
Finney relays that, to some extent, you can think of octane and burn rate in the same context, but burn rate largely stands alone in the company’s approach to engineering a fuel that meets the desire for a fast, clean burn.
A common mistake that racers make is in how they analyze and tune their machines, and a lack of consistency often falls on the fuel — in other words, at what point does the fuel take over from the racers’ mis-tuning? A great balance of racers tend to run on the rich side — they like to see dark on the plug, but Finney points out that such racers don’t know how to read a plug. But a plug should be clean.
“When a racer has tuned to the rich side, the car is going to be lazy in the heat because it can’t burn all of the fuel because of the moisture in the air. And then at night when it cools down the car suddenly picks up several numbers. So they’re constantly chasing the weather.”
Oxygenated fuels carry a wider tuning window and can somewhat curtail this, but Finney adds, “if you have a good consistent fuel that you can tune to the engine to, you can achieve nearly the same consistency with a non-oxygenated fuel.”
Finney closes by stating, “a fuel has to burn, and it can’t explode, and that’s the difference. Imagine nitromethane — you pour it on the ground and throw a match in it, it won’t light. But if you hit it with a hammer, it’ll explode and blow your head off. How it reacts to the cylinder pressure and temperatures is getting that fuel to burn and burn quickly without it just becoming dynamite. So our approach is all about finding that edge and staying right there on it.”