|
Street Class Unlimited Class
DOHC SOHC Ion Updated 1/05 For the most recent list of the fastest five cars click here. |
Intake TemperaturesBy: TitanThere is a lot of hype on the market about cold air intakes and many manufactures have touted the benefits of using them. There are several different kinds of intakes to choose from but most of the intakes that I have seen do not effectively isolate the intake from the heat of the engine compartment. Most cold air intakes simply move the point at which the air is drawn into the engine. Well here's a news flash for the manufactures, as long as the intake pulls air from under the hood it's still going to be hot air. Intakes are traditionally made from three kinds of materials metals, plastics, and polyethylene. All of these materials have different heat capacities i.e. metal holds heat much more readily then plastics or polyethylene, which leads to heat soaking and higher intake air temperatures. So what does one do in order to get the coldest intake temperatures possible? The intake needs to be both isolated and insolated from engine heat. This isolation becomes even more critical with turbo applications and the heat that they produce. The intake should not be made from metal. Hot metal intakes heat up the charge of the incoming air more readily. A ram air effect would help drop heat and add some horsepower. You are virtually guaranteed an air intake charge equivalent to ambient temperature using a ram air type intake. (this is cheap horsepower for you N/A people out there) In an attempt to design a simple experiment that would show under hood air temperatures I purchased a simple indoor/outdoor thermometer and taped it to the under hood fuse box (pic). Unfortunately, I could not collect reliable data to post. I believe that there were basically two factors inhibiting my experiment. The first was that the thermometer was unable to quickly adjust to the temperature changes. Temperature readings seemed to take forever to change on the screen and when they finally did there would be a sudden jump of 4-5 degrees. Secondly, I could not get a reliable "indoor" reading. I was using the outdoor temperature gauge to test under hood temperatures and the indoor gauge to test ambient temperature inside the car. The indoor thermometer would often be incorrect since it was normally sitting in the sun or in the hot cabin, which skewed the readings. Even with all the difficulty I could still make two observations. Sitting at a red light or idling for any amount of time makes the intake temperatures soar 90-100+. · While traveling at highway speeds the intake charge remains close to ambient temperatures. This figure had a lot to do with ambient temperatures i.e. hotter days will create a hotter intake charge. As you can see the jury is still out on this subject. But, if you can effectively isolate the intake from the engine bay temperature, eliminating heat soak, and add some type of a ram air to your car will probably attain more horsepower then most "off the shelf" cold air intakes. |
|
