Stealth performance air cleaner

Is there a way to feed a hungry engine when you NEED the airflow delivered by high flow air cleaner, BUT you want to keep the stock looks and fuctionality?

Can you really have your cake and eat it?

Yep   

I've been doing flow testing on various intake components to see what's what, with some interesting results. The stock air cleaner became a problem above 3000 RPM and was choking the non-stock engine.
First test was the usual paper element in a chrome air cleaner stuck on the carb. Engine now revs cleanly to 5000rpm, but there is no directional transition for the air; it comes in the sides of the housing, then crashes into all the other air molecules being sucked in, then makes a 90 degree turn down the carb and immediately meets the venturi. No room to radius the transition or add a short velocity stack.

Test two was re-installing the OEM style pipe that connects the original air cleaner to the carb. The main purpose of this test was to see if the pipe was a restriction, and also the see if the elbow gave more direction to the flow than when the air cleaner was mounted directly to the carb. The answers were no, it was not a significant restriction, and yes, it did improve the flow direction into the carb. Result of this last item was more low and mid range torque, and better part-throttle response.

Test three was re-installing the original air cleaner, testing, then adding a triangular cutout beneath the neck of the snorkel to increase available airflow. The cutout is hidden and brings the airflow capability of the snorkel to 300% of the original. Results showed that the cutout removed the snorkel restriction, but that the remaining restrictions were internal to the oil bath air cleaner.

In conclusion, the element filter flowed better than the oil bath air cleaner, the hidden cutout sucessfully removed the snorkel restriction, and the stock rubber pipe between the air cleaner and carb helped rather than hurt drivability.

Now I had to choose between letting the engine breathe, or keeping the dead-stock appearance of the original air cleaner, so I chose both by incorporating a performance filter element hidden inside the OEM air cleaner housing. A few photos outlining the job are below, but it should be noted that I did use a fine cutting wheel to slice the bottom of the canister open so it could be tack-welded back on. Making the cut higher up would improve flow, but I did not want to make a second cut that would make it more difficult to undo. I can't think of any reason to go back other than making it a purely show car or muesem piece. The new filter element flows better, filters better, and I keep the OEM damper and the preheater. Best part is that you can't tell unless you take it apart.

What are these? Horsehair biscuits?

Looking up into the housing after biscuit removal.

Same view, but after deep cleaning and installing rubber seal for new filter.

Here is the new element. It has the maximum surface area that will fit inside the stock housing

Same filter upside down with the mounting neck cut off. I used a Dremel, but whatever your method, do not cut off the pink portion. That is bonded to the element. The height of the new filter almost perfectly matches the space inside the original housing.

The remaining rubber can be peeled up and removed. This will be our sealing surface that contacts the new rubber seal inside the housing.

Here is the new filter positioned in the housing. You must install it with the housing upside down to make sure it is centered properly. With the element centered in the housing top, place the housing bottom in position, press down to compress the seal, then latch the spring clamps.

Flip it over and you are ready to install in the car.