Many of us still have our stock air filter box in the standard location (in front of the drivers side front wheel well). Some of us have bought cold air intake systems, cut open the bottom of the filter box, or both. Others have different filters, but have them located in the same “hole” in front of the wheel well.
All of these situations have something in common: location. The area in question is about 1.5 cubic feet in volume and has several small openings by which air can flow. For lack of a better term, I will call this area the air well. Unfortunately, these openings are relatively small and most of them suck air from under the hood (air that is already heat soaked). The only passage that leads to fresh outside air is located underneath the bumper.
The problem: when you stomp on the gas, the LT1 will quickly suck air out of the tiny 1.5 cubic foot air well where the filter resides. At 5,000 rpm, the LT1 consumes approximately 8 cubic feet of air per second! As air is depleted from (sucked out of) the air well, a (slight) vacuum is created inside the air well. The vacuum inside the air well causes air to enter the air well from wherever there is an opening into a (larger volume) space. It is important to realize that the smaller the holes in the air well, the less pressure you are going to have. It is the same effect as driving your car to the top of a mountain (where the air pressure is reduced) and running your car. The higher the air pressure at your intake, the more power you will make.
The solution: Any solution that supplies more air to the air well is a positive solution. The LT1 ram air scoop featured here has two purposes: (1) to increase the amount of outside (cooler) air available to the intake, and (2) to use an air scoop to increase the air pressure inside the air well at higher speeds.
The Procedure
1. Cut a piece of aluminum flashing into the shape shown above. I initially bent mine over a 4×4 piece of wood, so as a result, the size of my scoop ended up being 7 1/4 inches long x 3 5/8 inches wide x 3 inches in height. The flashing that I used was thin enough that all the bends that you see in the metal above were done with my bare hands and the corner of a piece of wood. Notice the lips on the sides and back of the scoop. These will go inside the air well later.
2. Cut out a rectangular hole in the bottom of the air well as shown above. When cutting the hole, cut the width of the scoop but do not include the lips on the scoop when making your measurements. Also, cut as close as possible to the outside (farthest from camera) of the car since the filter box is actually sitting directly over the hole in this picture.
3. Now push the scoop up through the hole with the lips (edges) of the scoop inside the air well as shown above. You can now place your hand inside the scoop to hold the scoop tight against the plastic and drill eight very small holes through both plastic and metal (don’t drill through your fingers though). These holes are only to guide the small screws. When tightening the screws, only tighten them a half turn or so past when you feel pressure since the flashing will tear easily if you try to make them tight. They should stay in without a problem. Since the lip of the scoop is on the inside of the air well, the air entering the scoop at high speed will only serve to tighten down, not pull the flashing away from the screws.
4. Now that the scoop is in place, you’ll want to cut off a small section of the front air dam so that air can enter the scoop easily at speed. Notice that the air dam has been cut off not flush with the left side of the scoop, but a little more than an inch past this so that turbulence from air passing by the air dam does not disturb the flow entering the scoop. At this point, I have not done any pressure testing inside the air well as it turned out to be more trouble than I thought, mainly because the air well has no easily accessible openings without removing the filter box. The amount of ram air effect is also unknown at this time. Obviously, the larger the scoop, the more air (and therefore pressure) will be injected. The size of the scoop pictured here is totally arbitrary. Scoops of (significantly) larger size are possible, but note by looking at the picture above that extending the scoop further to the right may require an odder shape due to the shape of the bumper cover.
What about rain?
I always get asked “do you have problems in the rain”. In short, the answer is no! The air filter box is actually quite a bit above the scoop and isn’t attached directly to the scoop so even if you were to drive through water deep enough to get in the scoop, it would have to slosh around in there for a while (meaning you’d have to be driving through the water for some time) before it got up to the level of the air box. As far as just heavy downpours, driving rain, or driving on the freeway with a lot of splash: no problem whatsoever because once again, the actual air filter is not connected to the scoop. I’ve been driving with this mod for about 6 years in all weather without trouble, but as with any “free mod”, do it at your own risk.
Performance gains?
I didn’t really notice any seat-of-the-pants improvement in performance, but the car no longer bogs down after sitting in traffic or hot weather while idling. The purpose of this mod isn’t to give a true ram air effect, rather, it is to open up the area where the filter resides to cool outside air. Sucking cool air from under the car is a lot more efficient than sucking it through the hot engine compartment so I definitely noticed more consistent performance particularly in hot weather.