I went down the boosted filter rabbit hole yesterday and here is what I found.
I have a Vortech T trim and a Spectre 9732 10 inch long, 4 inch flange filter now. I am looking for a better DRY filter that will make all the possible boost on my centri.

Searching here, YB and diesel forums I found the better filters to be R2C and AFE.

Forcefed86 has written:
""KN conical filters flow 68-72 CFM per sq./ft. at .5" w.g.
Spectre filters flow 170-180 CFM per sq./ft. at .5" w.g.

Both cause problems on big demand diesel engines.

R2C Black air filters flow 480-495 CFM per sq./ft. at .5" w.g.""

R2c is out of business as far as I can tell but some suppliers still carry the R2C 10537 filter comparable to the Spectre I have now. Kartek in Cali if interested.
https://www.kartek.com/parts/r2c-off...9-14-tall.html

So the diesel guys are looking for it all. Amazing filtering and flow. Someone found Donaldson nanotechnology filters used on heavy equipment to be the ticket.
Amsoil filters use this technology now and it seems to be the real deal.

https://www.amsoil.com/products/ea_f..._and_Specs.pdf

https://www.amsoil.com/shop/by-produ...ction-filters/

Diesel guys talking about it here:
https://www.turbodieselregister.com/...r-bhaf.129738/
Page 13 starts to talk about it.

The particulars are found here.

https://www.cumminsforum.com/forum/a...-pictures.html

The first page has pics. The comparable to my Spectre is the 4090 which flows 1000cfm at 16 " water restriction. The above competition from FF86 is rated at 5 " water.
Post 44 has flow charts and the 4090 flows about 500cfm @ 5" if my mouse skills are any where near accurate.

I am going to try and get the 4091 to fit and never have to deal with filters again.

Hopefully this saves someone a few hours of time down the road when researching filters or maybe I am just wasting my time and money for no gains. I am looking for max boost, filtering and ease of cleaning.

 

Let us know how it works out. How much power are you looking to make? I had a big (5" inlet, 9" long) AFE diesel filter on my S480. While I don't think it was much of a restriction on around 850whp, it was starting to collapse on itself which worried me.

 

355 LT1 here. Maybe 600 at the tire? Who knows. I did some measuring and the bigger 4091 isn't going to fit. The 4090 is the exact same as the Spectre I have now and will go with that. I don't think most Amsoil dealers will have it in stock so will order off the main website.

 

Stuck in the rabbit hole. Just found this on bob is the oil guy: ""We do not have the test information for each individual filter. We performed ISO test 5011 with SAE coarse dust. The test was performed on EAAU4090. As far as the results we found that at 350 CFM the restriction was 2.2 inches of H2O, at 500 CFM the restriction is 4.7 inches of H2O, and at 800 CFM the restriction is 11.5 inches of H2O. Since the filters all use the same media the results will be comparable. There will be slight variations based on size of the filter.""
So it looks like the 4090 flows more then 500cfm at 5" of water.

 

So do you think this would be a better choice for my whipple 2.9 then the 9 in K&N?

I read somewhere it flows 650 cfm?

 

I do. I have not found anything better so far other then no filter for best flow and a carpet for best filtration.
From what I have seen screw type blowers are sensitive to intake restrictions.

 

Well... this sucks....

Why OEM Filters Are Best

Dammit, going to need big MF'rs to feed mine

 

Thanks for sharing. More info the better. Two things I got from (quickly) going over that. It looks to me to be a test of filtration and dust capture and OEM is excellent. It doesn't look like a test of flow capabilities. Secondly the test was done in 2004. It looks to me that Amsoil switched to the Donaldson type nanotechnology around 2006-2007 and before that had foam filters which were known to be crap. I've had a 10 inch K&N in teh past and it showed signs of collapse but still managed to make good power.

 

Yes I am sure some have upped their game since 2004, what I got from the article was that nobody in the aftermarket has a vested interest in keeping our modified babies going for 100,000 miles, so they will just sell on cfm or BS that they flow better than stock. Filtration is important when engine life is to be considered, and clearly K & N (despite a lot of marketing to the contrary) plainly did NOT test well at all. This pisses me off because I bought into the hype and have 2 large K & N conical filters feeding my twin turbo LS3 that are filthy due to being rear mounted and sucking up dust and **** from behind the rear wheels.... I now hate to think what crap they have allowed into my engine and now need to completely rethink how I both place and filter the car without restriction. If I need to mount 2 x semi truck nano tech filters I'll do it when I rebuild as I want the built motor to last. Anything over 5-10 micron damages engines (causes premature wear) and you cannot see anything that small. Not happy to find my faith in my K & N's appears to be misplaced.

Big thank you for your effort on this subject as it made me relook at it and discover my fk up

As for cfm ratings - I think if you want max engine protection the answer is clear - go for an OEM filter that can flow the cfm you need e.g. 2 x OEM LS3 filters would flow an easy 900hp, 1 x a C7 ZR1 filter can obviously flow 755hp so 2 would be fine for up to 1500hp. I don't think there would be much power to be gained by reducing restriction as long as the cfm capability matches the engine needs at WOT.. Therefore I think engine protection becomes the most important thing. I cringe when I see turbos drawing in clear air.... that's a guaranteed limited engine life, not an issue on dedicated drag cars that need a rebuild every season anyway I suppose, but still that setup is only one **** suck away from disaster at any time.

 

Where your turbos are...you have the room.

As for K&N's sucking in.....I really doubt it is anything to do with a perceived restriction. It just seems that most K&N's go like that over time, even on very low powered applications.

But when you have plenty of room, there is no real concern anyway. Just get or make a housing for some big OEM filters and you'll have good flow and filtration forever.

 

My thoughts exactly Stevie. I could fit 2 Scania 730hp filters in my trunk lol, but still need room for a suitcase and bags around the meth tank and cage mounts. The K & N's flow good, but I don't want dirt in my engine. Going to block off the rear fender vents (where most dust gets in) by installing dust covers and oil coolers over the openings, then use NAPA ducts in rear side windows (lexan) to direct clean cold air onto filters. That'll clean the air. May run 2 x C7 ZR1 filters or get Ac Delco to spec some conical ones of suitable filtration and cfm

 

Just a FYI - R2C is still in business. I just called them today to see if that was the case. The person answered and stated that they were down for approximately 3 weeks in order to move from one town to another and get everything up and going, but they are in business:

http://www.r2cperformance.com
R2C'S NEW PHONE NUMBERS: 224-778-5454 & 224-778-5457 - Mundelein, IL

 

How about these filters?
http://www.r2cperformance.com/black-...l-filters.aspx

 

R2C filters are great. I don't have any hard data but I switched from a k&n to a giant r2c and the turbo became much more responsive. I had to lower the duty cycle on the boost controller about 10% to get the same boost with the new filter as I was with the k&n.


Sorry for the giant picture...

 

LOL engine master already did a test on filters and turbos and there was no difference in power through all the filters

 

When all the filters were the biggest they could find...that's no surprise either.

They need to test **** for problem builds...ie small filters as many are restricted for space for a huge filter.

 

CFM is one thing, getting clean air in is another. Most filters that flow well also let **** into the engine so to me size is irrelevant if the air is not clean enough. We need quality filtration if we want long engine life and quality filtration is not typically possible in a compact filter element. OEM paper elements filter very well, but need to be very large to flow the cfm required in big power motors

 

Not really. Look at a lot of OEM stuff these days, even cars making 3, 400hp etc, and some of their filters are tiny. Some of the Subaru ones are very small