1991 Non-Turbo Supra: Use of K&N air filter to boost hp and mpg?
 

My attention is focused on using performance air filters like K&N brand to increase horse power and potentially increase my mpg.

There is the option to swap out the paper filter for a K&N "oiled unit (E-2605-1), but there is also the option to use an adapter kit (57-9005) which also replaces the OEM air box and uses a different filter (RC-2960).

The design looks simple and I was wondering if I could just make an adapter myself and mount a universal cone shaped filter? I saw a clearance Power Adder unit on Clearance at Autozone for $12 and wondered if I could adapt my car to it. Anyone ever make use of universal performance filters?

This kit looks like it allows hot under the hood to be used. I thought it was best to draw cooler air into the engine. The OEM air box draws air forward of the radiator, whereas, the shortened kit (at least from the installation pictures) draws air that is rear of the radiator line.

Anyone with experience with either of these two methods? What were your results?

See FAQs section thread on this subject.

Response to using Air Filter Adapter
 

Before getting your post, I was modifiying a 4-inch Rubber pipe Cap from Home Depot ($3.88) to fit my 4-inch 'closeout' Power Adder air filter, so if that doesn't work, I'll check out the ebay adapters you mentioned.

I'm wondering why the K&N designers didn't suggest something to pull cool air from the outside instead of sucking in hot engine compartment air when using their FIPK (57-9005) kits? It only makes sense to me, but I'll test out my invention and "engineer" something like you mentioned that would help block the low restriction air filter from seeing hot engine compartment air.

Thanks,

Mitchell