Hopefully the below link works. Donaldson seems to have the most info online about their filter specs. Basically you can get the filtration of the bhaf with more airflow with a bigger filter, BHAF is used because it is the perfect size and hooks right to the stock hose.

http://www.donaldson.com/en/engine/s...ary/000622.pdf

I measured the space I had, picked a filter with appropriate flow, figured out a way to route the new intake tubing, cross-referenced the donaldson p/n, bought the filter, went shopping here for tubing, charge air cooler Hose, contant torque clamps. My project has been short on funds but will be together soon:
http://airflo.com/aboutUs.html
http://intakehoses.com/


Of course it'd be much easier to buy a afe

 

Of course it can flow enough to feed twins. It will just be SUPER restrictive doing so.

Filters are rated in terms of CFM (flow rate) at a given rate of restriction, usually a pressure drop figure in inches of water (8", 10" or so).

But you have to be careful as to what the "pressure drop" spec actually means. If it means that flowbench was set at a certain pressure drop, and the filter allowed a given amount of flow, then the LOWER the pressure drop the better. In other words, 200CFM @4" would be MORE restrictive than 200CFM @ 2". (i.e., it took less pressure drop to get 200cfm). This is usually the convention, from what I understand.

But there's another way to look at it. Rather than seeing flow caused by a pressure drop, some see the "restriction" as being caused by the flow. For example, I might get only 4" restriction when I try to stuff 200cfm through one filter, but I might get 8" restriction when I try to stuff that same 200cfm through another.

Adding even MORE confusion is that some people think that restrictiveness (the inches of water" is a measure of how well a filter filters. The higher the number, the better it captures dirt.

Anyway, let me illustrate how the confusion leads people to opposite conclusions:

We have two filters:

1. one flows 500CFM @10" water
2. one flows 500CFM @6" water

Which filter flows more air with less restriction?? Some would say the first does, because when the filters moves the same amount of air in spite of higher "restriction" and we can assume that when the filter is cleaner (and restriction drops to 8" or so), then the filter flows even MORE than the 500cfm.

Others would say that the SECOND filter flows more, because it only takes 6" pressure drop to induce 500CFM. By comparison, the first filter needs more pressure differential to allow the same amount of flow, hence the first is more restrictive and the SECOND is better flowing.

Who is correct??

 

The short answer is that a BHAF is not a good choice for twins. It's just not a high-flow filter.

Better than stock, yes--- but not nearly up to what twins (even small ones) need.

 

thank you very much thats kinda what i been thinking