A6qwDenver

I know this may be opening pandora's box....but has anyone done a cone filter conersion on a 2.8l 12v? Results?

Audiboy

JustDave, jussnb, Scott, Bryan - I think all the 12V A4 regulars have done a conversion

I have something in my picture poster but it's not quite a straight cone only conversion. But it shows you that you can use the stock box with a cone inside.

Depending on which cone you use, you get 5% or better efficiency of air flow at 300CFM's. That translates to more hp at high rpms.

JWG

A cone filter has the benefit of higher flow. However, most people choose to sacrifice air density because the cone filter (no matter how well you try to avoid it) will suck in hot air from the engine compartment, unless you relocate the battery and drill through the firewall.

I choose to retain the air box and panel filter, because BMW's 4.0 l V8 that makes 300 hp uses exactly the same size panel filter. So, the panel filter will more than adequately feed our 200-something hp engines.

The problem simply results from the length and size of the air way which causes the engine to work very hard to suck in air.

I elected to solve the problem by getting a high flow K&N panel filter and modifying the air inlet over the air condensor/radiator with an aluminum home-made ram-air-style extension. I get slight boost at speed; it really helps the engine breathe by forcing the air through the winding, form shifting, and constrictive passages before the air box. Thus, the engine only has to suck the air from the air box which has a fairly straight, even passage to the plenum. The benefit? The air comes from the outside, so it remains a "cold air intake", increasing the air density; thus, the amount of air available for combustion.