At my last chassis dyno run I found that I was losing nearly 30 HP due to my restrictive air filter. I was/am running the 21" x 10" x 1.8" oval K&N filter. No more room is left to run a taller filter either. I called K&N customer service and got them to pass me off to engineering. In talking with the tech I found that my existing filter is rated at 575 CFM before it starts restricting and causing a significant loss of horsepower. That's not nearly enough to feed my twin 750 Quick Fuel carbs on my KC Pond 482. The tech ran the engine numbers saying I needed around 900 CFM or so.
K&N has a very good site for selecting filters by size and seeing the engineering data WRT flow ratings. I found a 9" x 6" BWM 1000 motorcycle filter rated rated @ 372 CFM. That was my target physical size, perfect for nestling between the top of the 2 carbs in/on the filter lid. The combination of the 2 filters should yield +/- 950 CFM.
The filter is only 1" tall and after I mill the rectangular hole for it in the lid It will sit in the lid with 1/4" up on top and only about .6" protruding down into the air stream. That should provide me with the internal, non-restrictive internal flow I need. The interference fit should hold the filter in well.
Here's a few pics of the filter and it's install location. I ordered another lid from Barry_R so I'll have a non-modified lid for car shows etc. I plan on finishing the mod and hitting the chassis dyno for some before 'n after horsepower readings.
Results to follow...
