Cold Air Intake: Theory & Practice
A cold air intake is a device for supplying cold air to an internal combustion engine for increasing its power.
Consists of :
1. Filter zero resistance.
2. Air tube.
Used on both atmospheric and turbo engines.
A standard intake system most often has great resistance to the air flow. The paper filter and the manufacturer’s desire to reduce the noise are to blame. In addition, the air intake is usually made from the hot power bay (the engine section). All this reduces the engine power.
Cold air intake system difference
Basic principles of building a cold intake:
- Air intake from the coldest places..
- Putting the filter at the maximum distance from the engine
- Smooth intake tube - not corrugated to avoid creating air flow resistance.
- If possible, the shortest and remote from the hot parts of the engine tube from the filter to the intake manifold.
- Use of heat-resistant materials.
Advantages of the cold air intake system:
- Increased engine power - a few “horses” and more torque. For auto, the increase is smaller, for turbo - significantly more.
- Reducing a chance to get detonation.
- In hot weather, the engine doesn’t get slow.
- According to MechanicFAQ, sometimes improvement in the engine response to pressing the gas pedal and reducing fuel consumption is detected.
Disadvantages of the cold air intake system:
- Typical zero resistance filter noise (some people like it though).
- In extreme installation cases and vehicle exploitation, there’s a hydraulic impact risk.
By method and location of the filter |
1. The open filter in position with or without a thermal screen.
+ Design and installation simplicity.
- The air is not that cold (the system heats up like the stock one).
- The filter clogs pretty fast.
2. The closed filter with a regular place.
+ The system heats less due to the closed filter.
+ The filter stays clean for quite a while.
- More complex design and installation.
3. The closed filter at the maximum gap from the engine.
+ The system heats up much less because of the closed filter and its removal from the engine.
+ The filter stays clean for quite a while.
- Complicated design and installation - usually full custom, sometimes requiring a change in the layout of the engine compartment, like transferring the battery or technical fluids.
4. The filter nearest to the street.
- Under the wheel’s wing.
- Instead of the headlamp.
- In the bumper.
+ Very cold air.
- Big hydraulic impact risk.
- Complicated design and installation - you’ve got to pull the tube through half the engine scratching your own car.
- The filter clogs fast.
According to the location of the air intake
Considering the location of the air intake at the location of the filter in the engine. The air intake from the space under the hood variations are not considered due to the high temperature of the air.
1. From the headlamp.
+ Very cold air.
- Headlamp scratches are unavoidable.
- Quite a complicated structure.
- Filter clogs fast.
- Hydraulic impact risk.
2. From the bumper.
+ Very cold air.
- Bumper scratches are unavoidable.
- Quite a complicated structure.
- Filter clogs fast.
- Hydraulic impact risk.
3. From under the wing.
+ Very cold air.
+ Filter stays clean for quite a while.
- Quite a complicated structure.
- Minimum hydraulic impact risk.
Simple rules of the cold inlet installation process
Smooth insides of the intake pipes (no corrugation is necessary).The most direct and shortest tube to the collector.The zero resistance filter.
The advantages of the cold air intake include not only an increase in engine power but also lower chances of getting a detonation. In some cases, responsiveness to the gas pedal may improve and fuel consumption will decrease by a couple of percents.
Of course, there are drawbacks. This is the typical noise from the inlet along with hydraulic impact risk. The fact is that often the cold inlet is placed in the bumper and there is a small chance of water getting in there. Although the danger is rather contrived, to get a hydraulic impact you have to completely lower the end of the intake pipe into the water, otherwise, the engine simply will not create enough vacuum to suck it in.
Conclusion
In the simplest version of the cold inlet, the standard air filter housing is replaced with a short plastic or metal pipe with the zero resistance filter at the end. The growth of "horses" depends on how tightly the motor was clamped by a standard filter. In any case, such a system often involves placing the filter under the hood, and you should at least make heat shields and try moving the filter to the front, cooler part of the engine block.
A greater increase in power can be obtained by placing the air intake in the wheel arch, the bumper, or behind the grill (but in front of the radiator). A ventilation slot option in the hood and the filter (in a headlamp’s place) is also possible.
Green tuners rarely pay due attention to proper cold inlet management. It seems sufficient just putting the zero resistance filter on the standard corrugation or cutting around the “pot” on the carburator. Sometimes you can even see the filter hanging above the exhaust manifold. With such a scenario, after a couple of minutes of active driving, the intake air temperature rises to the obscene. Power falls, the car can’t deal with it. Those who consider the cold inlet insignificant should not be engaged in tuning at all.
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