Imperial Home Page -> Imperials by Year -> 1990 -> Modifications -> Cold Air Intake
One of the cheapest, and biggest HP per buck modifications for the 3.3/3.8L engine is the use of a cool air intake and the air box elimination. This modification can be viewed as worth while for the performance minded Imperial owner, or anyone who just wants better gas mileage.
The stock intake uses a highly restrictive air box, and gets the air for the engine from behind the front driver's side headlights. This stock method is restrictive, which hurts gas mileage, and sucks in warm or hot air, which is bad for the engine. The simple fix is just using a cone K&N filter and setting up a cheap system which gets air from outside of the engine bay.
To do this, one must unclamp the large hose which goes from the air box to the throttle body. Then the hose must be removed from the air box. The air box must then be opened, and all filters inside must be removed. Next, the air box unbolts. Then one simply removes the crankcase vent hose, and the air box assembly can be removed.
Next, a crankcase vent filter must be put over the hole on the crankcase where the crank case vent hose was located. Then a cone air filter can simply be clamped over the end of the large intake hose which went from the throttle body to the air box.
The air filter can be kept sitting between the relay box and the battery, or if cooler air is wanted, one can simply run large tubing/hoses from under the bumper up over the transmission to the air filter. Going down the road would cause air to enter the large hose/tube and the cool external air will then follow the tube to outside the air filter. The engine would then such the cool air into the intake manifold via the air filter and the throttle body.
Total cost is about $50 max. The result is better acceleration, better gas mileage, and sometimes as much as 12 HP more then with the stock setup.
The Mopar enthusiasts with the 3.0L V6 use this same modification all the time, and instructions with pictures for it can be found on many (most) of the web sites on the 3.0L V6 models.
Here is an example of this set up below.
As seen in the picture, a crankcase filter is positioned where the crank vent hose came from (see left side of picture). The air filter, in this case a cone filter located where the battery sat, can be positioned anywhere where it will fit and where the tubing/hoses for it will go. To add cool air to this setup, just run air ducting from under the bumper up to the air filter.