OK, I have done the search and reading of the posts but am not clear on some points.

Why would I need a filter that flows 320 cfm when a 110 cu" engine can onlyflow about 200 cfm @ 6200 rpm and a 88 only flows about 158 cfm @ 6200? Wouldn't the SE filter be fine on a 88? I have seen filters for $250.00 and some for alot less, what is the difference other than $$$?

 

damn good question! were are the experts on this one

 

That's like asking why you need a 110" motor in your bike, or need a 6spd transmission. Unless you are racing, you don't really need it. It's more a want.

Personally, I think the SE Air Cleaner is just find for what I have now, and what I plan to upgrade (if I ever actually do).

 

I was thinkin the same thing. The RK is gunna be 88 cu" till it breaks or needs a rebuild.

 

Ain't no expert on air filters, but ah DO have about 30 years experience on water filters, an' ah've got a sneakin' suspicion that the same principles apply.....

Filters are rated at "zero load" and ideal conditions - for a water filter, that means what it'll flow when NEW, with ZERO particulate load and at about 85 degrees (F). Warm water has a lower viscosity than cold, and filtered water will flow better that non-filtered because there's nothing for the filter to have to trap. If I take that same filter, rated at say 5 gpm and sell it to a customer needing to filter 5 gpm, he's likely to call me back in a few weeks ready to use that filter on ME. General rule of thumb on water filters is that I want 4x the desired flow as stated by the customer.

An air filter is gonna lose flow as soon as ya start the engine - and ambient air temperature WILL have an impact on the flow rates as well, since cooler air is more dense than warm air.


HTH....

 

The Zippers filter I installed in place of the SE A/C did make a very noticable difference in the bike. No dyno results but (butt) dyno was positive. Seems throttle response seems more immediate. Do this test, for all that disbelieve--remove the A/C and take a short spin.

 

The SE or Ness Stage 1 would be fine for an 88 and will out-flow the stock rig by a large margin.
The proof is in the fact that we MUST add fuel to get the mixture right after such an install.
The only reason you would "need" a larger filter than these would be if you rode in very dusty conditions and needed the added capacity.
We used to race a sportsman dirt modified racecar with a 14x6" K&N filter on top of a 500cfm 2bbl carb and 355cid chevy.
At the end of the night,you could almost tell there was an air cleaner on top of the engine,there was probably a quarter inch of dirt packed around the
whole assembly. When I would remove the filter to clean it,the carb would look new,and the car ran all night the same from clean to dirty.
I guess that would be a good reason to over-capacity the intake flow.
I don't think many of us will run at 6200 rpms for very long,so I would think more would be overkill.
I like the K&N type filters mostly for the increased filtering efficiency (and flow) over stock.
The stock filter will flow more "dirt" than the aftermarket filters,and that was the biggest seller for me.
Less dirt in = longer oil and engine life over time.
Mick

 

because,too much is still not enough.

 

maybe it's not the amount of flow,but how ez the flow passes by filter?

 

It's a combination of a number of things, includin' how many bends/turns the air has to make prior to enterin' the carb/engine. Every turn/imperfection creates additional "delta p" (pressure drop), which in turn requires the engine to work harder to draw the air into itself. That's one of the reasons that forced air systems can so dramatically improve engine performance (within reasonable bounds).