Added to the interior of the...
Added to the interior of the Fiero were manifold vacuum/boost, oil pressure, and water temperature gauges in addition to a tachometer. Not shown on the floor were exhaust temperature and fuel flow meters.
Smokey's Fiero was also quiet, started quickly and was responsive. A manifold pressure gauge mounted in the car reacted as if it was mechanically tied to the accelerator pedal. As the throttle was depressed, the manifold pressure instantly responded in a proportionate manner. Maximum pressure was intentionally limited to 15 psi. Smokey pointed out that the system would easily produce 30 psi manifold pressure if unlimited, but that much power would probably blow the head gasket or break pistons, rods, or the transaxle in the stock Fiero.
When asked how the stock transaxle was coping with the increased torque and power which incidentally was capable of lighting the tires on the Fiero, Smokey replied, "The expander cycle setup provides such even and controlled combustion that the cylinder pressure curve is more rounded with no spikes so the drivetrain isn't subjected to that impact wrench effect that breaks things. However, if you abuse the power you can break the transaxle."
When queried about internal engine changes, Smokey stated that the only internal change was the camshaft to make maximum utilization of exhaust heat and to provide maximum cylinder scavenging. All else was left stock.
Other benefits include elimination of the fan and reducing the radiator to half the stock size. Heat from the cooling system is used so efficiently in the first stage vapor generator that there's very little heat left to dissipate through the radiator. Smokey claims you can overcool his system, but you can't make it overheat, and that there is absolutely no possibility for carburetor icing.
It is possible to improperly design the Smokey setup and overheat the incoming air/fuel mixture, however. If the mixture (working fluid) is heated above 440 degrees F, detonation can begin to occur and adequate cooling of the valves becomes a problem. Combustion temperatures typically run 100 degrees F higher than in a normally aspirated engine. However, on an engine built to withstand the stress, maximum manifold pressure could be allowed to exceed 15 psi for power outputs in excess of 1.8 hp per cubic inch.
Other points of interest about Smokey's Fiero are that it represents a return to relatively simple engines. There are no computer controls. The carb remains virtually stock. The ignition system, although fitted with an MSD amplifier, is otherwise stock, and the ignition remains stock, too. Because the engine is artificially aspirated, there is virtually no loss of performance at altitudes up to 5,500 feet, and above 5,500 feet, it is still better than a stock normally aspirated engine. The "expander cycle" engine is also not very fussy about fuel quality. All mileage testing was done on EPA-rated fuel, but utilization of low octane fuels or alcohol requires only a minor rebalancing of the intake system in terms of preheating, which is controlled by sizing of orifices in the heat loop. There is also a minimum of emissions equipment.
Most people assume Smokey's system uses a very lean mixture which is not true. A lean-burn system doesn't get the maximum BTU content out of fuel. Lean-burn is a negative to thermal efficiency. Oxidation of gasoline must be at stoichiometric (optimum proportions) to get a full 17,500 BTU from each pound. Lean-burn won't give mileage and it doesn't make power.
Obviously, this breakthrough signals the beginning of a whole new plateau of engine development. As we said in the beginning, many consider this to be the most significant development applicable to the spark-ignited internal combustion engine in this century. Worldwide patents have been applied for and a well financed corporation has been formed to handle the marketing and licensing of the system to the major automotive, truck, aircraft, and equipment manufacturers. It's just possible that in a few short years many new car engines will be fitted with a form of Smokey's system.
So where does that leave the hot rodder? First, it means a return to high-performance engines that you can work on. It also means performance on a relatively poor grade fuel. Small, light, yet powerful engines will mean better handling and braking to match the acceleration potential. On a less happy note, it will probably hasten the emergence of four-cylinder engines and speed the demise of the big-inch engines that used to be required for performance.
In the immediate future, retro-fit kits for the Chrysler-built 2.2-liter and the Pontiac Iron Duke 2.5-liter will be offered through a division of Crane Cams in approximately one year and other retro-fit kits are bound to follow. Someone might even do kits for small V-8s.
And what about the long range future? What we've outlined here is only Smokey's first stage. Smokey is already developing stage five with exotic non metallic components, no cooling, and operating temperatures approaching 4,000 degrees F. Aren't you glad Smokey's one of us-and don't let anybody tell you hot rodding is dead!