It’s 1850 and you are driving a team of oxen, pulling an overloaded Conestoga wagon heading west across the featureless plains on the Oregon Trail. As you clear a rise, you come across a body lying face-down in the dirt with a dozen arrows sticking out of his lifeless body. That, friends, is the definition of a pioneer.
Now dump that Conestoga wagon and replace it with a 1969 Camaro and a pair of modern-day pioneers: Dale Vaznaian and Karl Staggemeier. Their quest still involves dodging technological arrows, but these are the kind fired by the nuances of perfecting the art of running a high-performance, internal-combustion engine on compressed air. They call their company Compressed Air Supercharging (CAS), and the name says it all. HOT ROD first covered this story in the Oct. 2014 issue (“Compressed Air Supercharging”). On the surface, the idea is simple: take 3,300 psi air from a bottle, use a combination of electrical and mechanical components to control the flow of air so that engine intake manifold pressure (boost) can be maintained at target levels. The combination of cold, compressed air makes effortless power while matching big power with outstanding engine reliability.
HOT ROD first covered this story in the Oct. 2014 issue (“Compressed Air Supercharging”).
Our first story tested the practical application of that pioneering theory on a very conservative 355ci, 422hp, normally aspirated small-block Chevy. With compressed air blowing through an Edelbrock Pro-Flow EFI manifold, the CAS system produced 836 hp. If you haven’t read the first part of this story, we would highly recommend you do so. Much of what we cover here will make much more sense with that information cold-compressed in your head.
Beyond the impressive power numbers was the revelation that the engine didn’t appear to need high-octane fuel to make this much power. Our initial test was run on 114-octane Rockett Brand Racing gasoline to be safe, but all track testing has been conducted using 91-octane pump gas with zero tuning or detonation issues. While the initial testing was performed on Westech’s engine dyno, the proof for the CAS system would be to make it perform flawlessly on the dragstrip.
Before we immerse ourselves too deeply in the fun side of a 9-second dragstrip pass, there are some important aspects of this system that need to be detailed. In our first story, the explanation of how this system functions could lead you to believe the CAS system is a power-adder much like a supercharger or nitrous system. According to Staggemeier, “It’s much better to look at this system as a power-replacer, not a power-adder. Think of it as replacing the atmosphere the engine uses rather than adding to it.”
This requires some out-of-the-box thinking, but hang with us. Normal atmosphere at sea level has a given density because air—even as light as it is—has weight. It’s something that physicists call mass. This atmospheric mass of air has a given number of oxygen molecules for every cubic foot of air. It’s those oxygen molecules that support the combustion of the fuel when combusted in the proper air-to-fuel ratio.
Now think about what would happen if we increased the density of the air introduced into the engine. That would be a good thing, right? We still have the same relationship of nitrogen to oxygen as in our normal atmosphere (78 percent nitrogen, 21 percent oxygen, and 1 percent a bunch of other stuff), but by compressing the air, we have increased the density of that oxygen-nitrogen mixture shoved into the cylinders. So the CAS system introduces its own atmosphere on board, feeding a greater charge density into the engine. It cannot be a power-adder because its dedicated atmosphere is creating the effective power rather than adding power to the existing normally aspirated combination.
The key to the added density is the result of not only boost pressure but also the incredibly low temperature of the air. Compressed Air Supercharging has recorded discharge temperatures as low as -850 degrees F. The air absorbs some heat on its way to the engine and does warm slightly as it enters the engine, but it’s still really cold. This incredibly low temperature radically increases the density of the air molecules, packing them closer together. If you consider that power increases 1 percent for every 10 degrees the inlet air temperature is reduced, you can begin to see why the CAS system works so well.
Staggemeier says this first CAS system pushes sufficient air to make between 850 and 900 hp. This means if you have a 250hp four-cylinder engine, adding the CAS system will push that engine to 900 hp. As we’ve already shown in the first story, the 422hp small-block produced 836 hp and would have made close to 900 had the tuning been optimized (that combination was limited by the size of the fuel injectors). This also means that if you were to bolt this same CAS system to a normally aspirated, 700hp big-block Chevy, it would still only make 900 hp. That’s the mass of air being pushed through the engine, regardless of the engine’s displacement.
The partners would prefer to deemphasize this for now, but the standard CAS pressure regulator is configured to support a paired system that would double the flow capacity of the system to support 1,700 to 1,800 hp. Given sufficient demand for a system with this much capacity, they can easily build this much potential power. But that’s in the future. For now, the initial CAS drag-race package will support 900 hp.
The elegance of the CAS system is that the extremely low discharge temperature and a mild 8 psi of pressure pushing the air combines to be extremely gentle on the engine. During initial dyno testing, an oversight led to running the engine at over 15:1 air/fuel ratio for a short period. With a turbocharged engine on gasoline, even the suggestion of a lean air/fuel ratio usually results in significant internal engine damage, and at the very least it destroys the spark plugs. But on the CAS engine, an inspection revealed no damage and not even the suggestion either in the chamber or on the spark plugs that anything negative had even occurred. This can be attributed to the extremely low inlet air temperature that radically reduces the engine’s sensitivity to detonation. Compressed Air Supercharging certainly does not recommend running this system with a lean air/fuel ratio, but if an accidental lean issue occurs, CAS’s experience reveals the engine will likely not suffer damage. You certainly can’t say that with a turbo, supercharged, or nitrous engine.
Once the system was installed in the Camaro, Staggemeier and Vaznaian ventured out to Fontana, California, to the dragstrip during multiple weekends to test the combination and fine-tune the modulation of the amount of air to be delivered on the starting line. This is critical since, much like a nitrous system, few suspensions and tires can handle when they are hit with 700 lb-ft of torque right on the starting line. So a critical portion of the CAS system is aimed at electronically modulating the power at low speeds to help launch the car.
The guys have put dozens of laps on the Camaro in the last few months. The driveline is very basic with a TH400 trans with a 4,200-rpm stall-speed converter (under boost) that feeds back to a 9-inch rearend with 3.70:1 gears and 35-spline axles planting the power through a ladder-bar rear suspension and 32x14-inch-wide Goodyear slicks. The car weighs 3,390 pounds with Staggemeier behind the wheel. The most recent test session delivered an excellent 1.39-second 60-foot time, which means that critical transition phase to full power is working really well. The Camaro’s best time to date with the near-900hp package has been 9.89 seconds at 134 mph on pump gas.
This is important because it’s relatively easy to put an engine on the dyno and run it at maximum rpm, hit it with compressed air, and make power. It’s much more difficult to install this same system on the car and use an electronic controller to manage the introduction of the compressed air into the engine in a fashion that doesn’t overpower the car. As you can see from the power curve we’ve included with this story, 700+ lb-ft of torque at 3,500 rpm would not be the easiest thing to control in terms of starting-line traction. So CAS has created an electronic control algorithm that manages this power down low for the first few seconds when the CAS system goes active. After that launch sequence is completed, the system achieves 100 percent flow, and it will be up to you to figure out how to plant all that power to the ground.
Currently, Vaznaian and Staggemeier have aimed this system at the drag-racing marketplace. The advantage is incredibly reliable power that does not create nearly the stresses induced by other power-adder system types. This system is not for everyone, but if you like the idea of big power from an engine requiring no special fuels, no special spark plugs or custom timing curve, or hassles with blower drives or intricate exhaust plumbing, a CAS system might be the answer. You can have a mild small-block Chevy capable of running high-9-second elapsed times in 1,320 feet—at the push of a button.
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