https://dodgeforum.com/m_269793/tm.htm

basicly keep in mind that as filtration increases flow is decreased and vise versa as flow increases filtration is decreased. The ultimate would be 0 ppm of dirt or dust and still have 100% flow. We all know that this is not going to happen. think of it like putting on a dust mask or a respirator, you breathe better without the mask ie. higher flow but more dust your breathing in, now if you put the mask on and filter the dust out breathing takes a bit more effort. the reason a k&n filter seems to add power is because it allows the engine to breathe a little easier. to much dust and dirt particles get inside of an engine and act like fine sand paper. Look at all the problems the military has been having with their engines in the desert in iraq the dust is actually choking the motors out. I know that it is a bit of an extreme example but gives examples of the effects dust can have.

 

Among the people who study
bore wall wear
valve seat wear
and piston ring wear
there seems to be a conclusion
that there is no 'acceptable' level of dirt particles.

The more dirt particles that get by,
the faster the increase in wear of those areas.
This would indicate you should buy the best % trapped filter.

But even an engine drawing in perfectly clean air,
would still have wear - most of it from carbon particles.

If you could 'magically' turn those carbon particles from
'amorphous' to graphite form
you could turn a wear enemy to a wear reducing friend.
{please send me $1000 when you get your patent}

Keep in mind that large industrial engines with piston speeds
near the 'best economy' speeds of 1200 feet per minute
and high quality air filters and oil
can exceed 25,000 hours of operation
which is in excess of 1,000,000 miles in a vehicle.

I personally know two people who have driven vehicles with engines
that went more than 1,000,000 miles - my brother with a Cat 3406
and a friend with the Renault diesel in a Mack Midliner.

 

Thanks Hank. as always, your a wealth of technical knowledge. I love reading your posts.

 

Some diesel owners who don't like K&N are using BHAF filters. WIX, NAPA and others make this style of filter. 4" inlet diameter.

 

Sweet. I think my FIPK tube is 4 inch. I'll have to look into one of those.

 

Here is another angle to look at. Filter A is 3 percent more efficient than Filter B at removing dirt but it is 4 percent less efficient in airflow. We get stuck at comparing the same size filters. If you restested the same brand filters that have 10% more surface area, would Filter A then have equal or better airflow than the smaller Filter B? Let's assume that it does. Then the engine would be drawing the same amount of dirty air through the filters, but you would still end up with less dirt in the engine from Filter A.

To summarize, I think you are better off installing a larger filter that has a better filtering ability.

I think some people do upgrade their intakes and put on larger filters, but then think that WOW!, if I put on this really big high flow filter I can get even more power out of the engine! There is going to be a threshold where increasing filter size will not increase airflow. This is where you want to be, then go with the filter that provides the best filtration. Of course this theory doesn't work if the filter size is too large that you can't fit it into the engine compartment.

One other thought. Where is the best location for the filter? Immediately above the intake or at the front of the truck? My preference is above the intake for the following reasons: The closer you are to the source of the vacuum, the more air you can draw through the filter. The tubes and elbows provide friction losses that will reduce airflow at the filter. I accept the challenge that the distance is so short that friction losses are negligable and this may be a mute point. The biggest reason though is again filtration. Any joints in the tubing can leak, resulting in unfiltered air getting into the engine. I have read stories about guys pulling off their aftermarket CAI and finding rust in the metal tube. That is scary.

I've been researching and thinking about a CAI for my truck, but haven't decided on the best setup. Based on my commentary above, I'm leaning towards going real cheap and installing a a piece of tubing from the stock filter housing and routing it to the front of the truck. The more expensive option would be to purchase a round filter and sealed housing that sets on top of the throttle body with tubing going to the front. I've seen some photos of this style setup and I like it.

 

That's some good points. I do agree that there is a point were you have maxed out the amount of air that the TB and in the end the intake will take in. I have read others who reported actually loosing low end torque when they upsized their filter too much, it's all about tradeoffs I guess.

I used to have an Airaid cold air intake setup, it had the metal tube. After only 5 months of use, I removed it to replace it with my K&N FIPK, and noticed rust in the tube. I am fairly positive that it is not from leaks or outside air getting into the tube unfilter, I beleive it was simply condensation that formed and rusted the tube. Either way, that is another reason I would never use a CAI that has a metal tube. They look cool, but rust that is on the intake side of the filter is very bad.

Though I agree with you about air flow and filter distance, I like my filter up front by the grill so it is pulling in cooler air. I believe that the filter size I have is letting in as much air as is needed Placing the air source immediatly above the intake might give me additional air, but if I can get that by just putting a bigger filter down by the grill, and get the same amount of air up by the intake, except cooler, that that is the way I prefer. I think one of the best setups would be a shaker type, or hood scoop type (forward or cowl induction). You would still get the benefit of cooler air rather then engine compartment air, but it would also be coming in very close to the intake, so flow would be less restricted and air would be abundant.

 

the buttdyno is all the graphs and readings and data that i need...

 

I knew you could lose low end by oversizing the exhaust, I hadn't read that about increasing the size of the filter. That's interesting.

As long as you are pulling the cold air from the front of the truck, I'm not sure that having the filter up front is an advantage, other than you can go with a larger filter. I've wondered about Dodge pulling the air from the fender. Guess how air gets up into the fender well? Due to the inner fender skirt, it has to go between the wheel and the exhaust manifold. I just took a look at my truck and realized that.

I agree that a hood scoop would be the way to go. Plus you are pulling the air from a higher location. HankL mentioned about truck engines going a million miles before an overhaul. Where do they get their air, from a high location. The intake on some rigs is in line with the bottom of the front winshield. This would be about at the top of the cab of our pickup trucks. I wonder if the air is cleaner at this location? I realize that fine dust can easily travel to this height, but is there less of it? Just thinking, and getting off topic.

 

No, that is why I wanted to start this topic. I wanted more indepth discussion of air filters and air intake then the usual "which CAI should I buy and oh, by the way, what is a CAI".

I misunderstood what you said earlier. Yes, I agree, filter location is probably better closer to the intake as long as the air you are pulling into that filter is not also coming from that location. Outside air I beleive is much better then under hood air. Another advantage of having the filter very close to the intake is you eliminate the risk of accidentally pulling in outside air in the event you get a crack or some other compromise along the length of tube between the filter and the intake.

RM_Indy has a good setup I think. http://www.rm-indy.com/mods.htm
He has a round air filter located directly on top of the air intake, with twin tubes coming from the front grill. Very similar to a setup I had once on a 3rd Gen Z-28 Camaro. It was a 5.0 305 HO with a Dual Snorkel Intake (I attached some pics of what this intake looked like). Air gets pulled in from a nice cool location, but is filter directly above the intake. Only problem I have with RM_Indys set-up (no offense RM_Indy, because we all know how bad *** your truck is and I have nothing but respect for your rig and the work you have done to it) is that the snorkel tubes kinda look cheesy since they are essentially dryer ducting that can be purchased at Home Depot. If there was a better looking tubing, that would look even more awesome.

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