Guys, the K&N FIPK is totally different from a drop-in filter. As seen in some of the photos posted above, the surface area of the FIPK is much greater than the rectangular OEM-style filter. In addition, the FIPK installation procedures call for opening up the lower radiator cover a bit (kinda like the space from a door being opened approx. 10 degrees) of cold air in. This setup is good for at least 10 RWHP.

The other thing that I've known forever is that paper filters flow very well when they are clean. But as they trap dirt, the pressure/flow drop can become significant. The hi-po oiled filters don't show nearly as much performance degradation over time.

 

Dave, look at the data in the dust delivered graph in the report. What it shows is that the paper filter has more restriction at the start of the test, but it has a pretty linear response to dust over time. More dust more restriction. The problem with the oiled filter is that it can't hold as much before it becomes overloaded and once it is full it is done filtering. Look at the data, once each filter has trapped 200 grams of dust, they are equal in flow restriction. Once you get higher than that the oiled filter is essentially full and it has a HIGHER restriction that the paper element. This is a direct result of the higher surface area of the paper filter. It can trap more dirt than the oiled filter, and hold on to it better. Once the oiled filter has covered it's surface in trapped dust, it can't trap more dust, the dust just bounces thru. That's why if you use one of these you need to clean it often, because once it gets loaded you have more restriction AND lower filtering effectiveness than a paper filter.

 

I put a Granatelli cold air kit on my 01 tahoe. now i get the deep roar when the throttle body is opened. By eliminating the baffling that quiets the intake roar, the air still has most of it's velocity as it enters the tapered cotton filter, and emits the roar from the filter
The increase in power that I got I think is in the straight tube that feeds the throttle body, and the elimination of heat from temp. saturated intake ducting.
On the tahoe, which is a LM7,(cast iron 5.3 LS1, alum. heads) the architecture is the same as the corvette, except the intake is the "big ugly", you can feel the difference after the kit was installed, but there was two feet of ducting with baffles and a flat 90 degree turn.
On the corvette, it's a gentle 90 and straight in. so there's not going to be as much improvement until you get to 5000 RPM or 5500 RPM . So buying a hipo filter for the C5 is almost worthless unless you keep the engine in the upper RPM ranges.
There may be a lag in the velocity of the air through the original paper filter, but not in the air volume required by the engine through most of the RPM ranges.
There is a book called 101 Projects for Your C4 in which the author figures out the air flow required for a 350 engine, and he was justifying the 600 cfm MAF, in which he came up with a 350 engine at 5000 RPM will need about 540 cfm.
If you look at the filter, MAF, throttle body, and ducting on a C5, you realize that compared to the L98 stuff, This airflow path is already adequate for stock or mildly modified, and unless you have a Z06, 5.7 is still a 350 ci engine.
The exception may still be in trimming the stock filter enclosure to pass more air into the filter, but at risk of ingesting water during a rain storm.
I am sure R&D engineers at chevy spent more than 15 minutes calculating intake air requirements and filter design since the C5 languished for almost 9 years in the wings of the General's engineering and design studios waiting for the proper time to manufacture it due to financial constraints that plagued GM at the time.

 

I'm not saying this didn't happen in the test that was posted, but I went 12,000+ miles (over 2 years) using my Halltech Stinger Warhead filter and even though the cold air side was dirty, the inside of the filter and all passageways right up and through the throttlebody were immaculately clean. Keep in mind that the Warhead filter, like that of the Blackwing filter is synthetic - unlike the K&N, which is made of cotton. The reason I mention this is that some people may infer from that test that only paper filters keep an engine clean, and that just isn't true in my book.

 

From what I've read here in the CF, one of GM's concerns when designing the intake system was noise. They had to compromise there and at the exhaust end of things to satisfy internal requirements (restrictions) of noise levels. Let's consider runflat tires in a similar vein. They satisfy the need of some people who cannot drive without a spare or some other means of ensuring they will not be stuck. Again, however, this decision compromises ultimate handling and performance. I could go on and on, but the point here is that there are many things that influence product design. Slapping on an aftermarket intake and getting 10+ RWHP is a no-brainer as long as the filter does what is expected.

 

So what do you guys think about a Vararam or a Black wing compared to stock filters or K&N filters?
I have an 03 coupe that I will use as a DD for the next 5 years....and I am concerned about longevity of the engine.

 

As with any intake system, always make sure its filter is sealing adequately:

http://forums.corvetteforum.com/show...917&forum_id=1

 

i went back and looked at that thread, and it looks like whoever oiled their filter, over oiled it, and instead of trapping dirt, the oil blew through the duct and oiled everything behind it. over time, the black dirt u can see there is probably ultra fine particles that have built up over time.
The guy with that t/b probably is one of those guys that reads the advertising, and that's what it looks like after 50,000 miles.
Also, i have seen two different guys go out and just spray more oil on the filter cause it "didn't look very wet" so who knows

 

I can say without much doubt that the filter used in that scenario was not a K&N, Halltech, or Blackwing. By the way, here's one of my posts a while back:

In the "Technical Correspondence" section of the latest Road & Track magazine, a reader wrote that he was getting a "Check Engine" light shortly after cleaning and oiling his K&N air filter in his 2000 Nissan Maxima. The dealership found the MAF sensor to be malfunctioning and directed blame at the filter. The reader's question was whether or not this could be true. Tom Wilson of Road & Track responded:

"Excess oil can foul the mass air sensor, and people tend to over-oil K&N filters while servicing them. It's easy to do as it takes time (hours) for the oil to migrate to all parts of the cotton gauze, tempting additional applications of oil.
K&N gives detailed instructions in their filter service kits, and supplies oil in aerosol form to ease oil application. It doesn't take much to service a filter; at the K&N factory the brand-new, never-oiled filters are given a quick bead of oil that in no way covers or comes close to saturating the cotton filter element. Yet by the time the filter is packaged and travels to warehouse and then to retail store, the oil has migrated throughout the filter to form a uniform red color."

Folks, please heed this warning and spray very lightly when oiling your K&N, Halltech, Blackwing, Volant, etc air filter after cleaning and drying it. The health of your MAF sensor depends upon it!

 

FILTERS are like cars everybody's got a favorite.
use what you think is going to work for YOU!
then you can go to your club meeting and browbeat the guy that doesn't have what you have