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FAQ'sCloud Car Transmission Problems Cloud Car Performance Intake Cloud Car Performance Ignition Misc.Car InformationThe Society of Automotive Engineers Car EnthusiastsCar Parts Vendors |
Cloud Car Performance Intake FAQ
The below list represents a collection of commonly asked questions concerning the induction system. While meant specifically for enthusiasts who drive the Chrysler Sebring Convertible, Chrysler Cirrus, Dodge Stratus, and/or Plymouth Breeze, the concepts presented here can be applied to any vehicle. If you have any further questions about induction, please feel free to e-mail me, and I'll answer, and maybe even put the question into this list. What is the K&N drop-in filter part number for my ride? The part number for the drop-in replacement K&N FilterCharger element is 33-2067. Why mess with the induction system at all? The stock factory induction is very restrictive to airflow. This means that the engine draws in less air than it theoretically can, which results in the engine not being able to produce as much power and torque as it theoretically could. The chief restrictions in the induction system are the stock air filter housing, and the rubber piping that connects the housing to the throttle body. The factory equipment was designed to give quiet engine intake noise while sacrificing as little performance as practical, as determined by the perceived customer base for cloud cars. Performance gains are realized by replacing the factory equipment with a higher-flowing aftermarket setup. For example, a cloud car with the 2.5L Mitsubishi V-6 will realize a 5 HP increase at the wheels (with a 7 ft-lbf torque increase) from installing a high-performance aftermarket induction tube. Also, if it were possible to actually stuff more air into the engine than would otherwise be possible with natural aspiration (which means that the engine alone draws in air), a significant performance increase can be realized. This is the theory behind turbocharging, supercharging, and nitrous oxide injection systems. Why not simply take the stock tube and filter assembly off and let the engine directly breathe? This is a bad idea for sustained driving periods, because the engine would breathe in dust particles that would collect in the engine oil. Eventually, the abrasive action these particles induce would cause excessive piston ring wear, excessive valve guide wear, and excessive hydraulic lifter wear. The engine would have to be rebuilt or replaced, at great cost. For temporary situations, it really depends on what driving style is to be expected with induction equipment removal. While it is a good idea at all times to keep some form of air filtration installed to the engine, short drag-racing style excursions would benefit slightly from letting the engine breathe directly as opposed to racing with a performance induction tube installed. What constitutes a high-performance induction tube? A high performance induction tube would ideally consist of a high-flow air filter connected to a tube with as few restrictions as possible, with bends and fittings considered as restrictions. Such a tube would ideally be situated so as to draw in air from the outside of the vehicle, as opposed to the engine compartment, so as to draw in cooler air than what's inside the engine compartment. This is because, roughly speaking, a 10 °F rise in inlet air temperature corresponds to a 1 HP drop in engine output. Finally, the tube itself would be made out of a thermally insulating material, such as carbon fiber or plastic, rather than metal. Would an aftermarket induction tube be noisier than stock? Yes, if a performance tube is installed in place of the stock equipment. The stock induction equipment was designed to limit engine noise at the expense of performance. The noise level will increase somewhat, but is really not bad at all for our cloud cars. What's the idea behind turbocharging? A turbocharger is a device that utilizes engine exhaust to drive a turbine at high speed. This turbine then drives an impeller that compresses air and sends this compressed air to the engine. Turbocharging is often employed where space considerations and/or mounting considerations dictate that a supercharger would be next to impossible to install. Turbochargers are also utilized when it is desired to easily maintain the air pressure before the throttle body at a fixed pressure regardless of engine load or elevation. Turbochargers typically include a wastegate to control the amount of exhaust driving the turbine, which in turn controls the amount of boost that the turbocharger can provide. This is in comparison to complicated and failure-prone methods that must be employed to make supercharger boost control achievable. What's the idea behind supercharging? A supercharger, in the common usage of the word, refers to a device that draws its power directly from the engine to compress air for combustion. The term "supercharging" can actually apply to any method that increases the air content going into the engine, as with turbocharging and nitrous oxide injection. Superchargers generally come in two types:
Positive displacement superchargers utilize some mechanism to physically move air from outside and then displace it from the pumping mechanism to the engine. The advantage of this design is that it pumps air immediately. However, if there is no way to relieve discharge air pressure, the supercharger can actually cause the engine to destroy itself from overpressurization. Impeller superchargers utilize a high-speed impeller to suck air into the engine. Impellers are more reliable than positive displacement superchargers in that there is less danger of overpressurization. However, impeller superchargers tend to heat up the intake charge more than positive displacement chargers.
What's the idea behind nitrous oxide injection? Nitrous oxide injection actually serves two roles. The primary role for nitrous is to add more oxygen to the combustion chamber than is normally possible. If more oxygen were present, more fuel could then be added for complete combustion, resulting in a performance increase. Nitrous is composed of N2O molecules, which break apart into N2 and O2 gas at temperatures above 500 °F, such as the pre-ignition temperature of a compressed charge in a combustion chamber. It is this decomposition that gives the extra oxygen necessary for the performance increase. The secondary role of nitrous is that as it is added, it evaporates in the intake charge, and causes the intake charge to drop in temperature. The temperature drop causes the intake air density to rise, allowing more air to be drawn into the combustion chamber. What are some drawbacks to the above-mentioned forced induction methods? Drawbacks of forced induction systems include having to retard ignition timing and installing complex methods of extra fuel delivery. Both of these drawbacks deal with the engine's tendancy to quickly destroy itself from over-lean fuel-air mixtures that result in very high combustion chamber temperatures and high-pressure shock waves from detonation. Also, with turbo/supercharging, the physical act of compressing air increases the air temperature going into the engine due to real-world inefficiency of both compression systems. Intercoolers will drop this air temperature once compression has occurred, at the expense of lowering the pressure of the compressed air. This is usually factored in when the turbo- or supercharging system is designed for a particular vehicle. Both turbochargers and superchargers also require some form of lubrication or cooling to cool off the bearings in these devices. Lack of sufficient lubrication/cooling will cause greatly shortened turbo/supercharger life expectancy. Supercharger systems typically cannot control the amount of boost pressure as well as turbocharger systems, and supercharger boost control tends to become more complicated (and easier to break) than turbocharger system boost control. |
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This page last updated 20 April 2010. |