Dear group;
I am of the opinion that hi-flow air filters don't actually do all that much to increase overall performance and the damage they are likely to cause from increased engine wear doesn't justify the added expense of these new hi-tech wonders. IMVHO, there is a MUCH simpler method of determining when an air filter replacement is necessary and it consists of nothing complicated than a stock Toyota vacuum differential switch a couple of vacuum lines, 2 wires and an idiot light. These switches are found on the oil bath air filters of the Toyota FJ-70 2F series engines. This is how they work:
The switch is a simple setup in which two vacuum hoses are connected to it. One of the hoses is connected to a nipple which measures air entering the carburetor before it passes thru the air filter and the second hose is attached to a nipple that is measuring the air after it has passed thru the filter and is on it's way to the carbs' throat. As long as the vacuum differential remains within 3hg of each other, the idiot light on the dash remains off, but once 3hg of vacuum has been attained, the switch activates and completes the electrical circuit and the bulb illuminates, informing the driver that the filter needs to be serviced or replaced. This is a very simply, fool-proof and cheap way of telling when the air filter is clogged and is no loner doing it's job.
Your friend;
LAMAR