Spicer’s air filter study

[cit1991]

I’ve seen a bunch of posts on aftermarket air filters. I found a new site hosting the original Spicer air filter study done for the duramaxes. It was an important posting back in the day, so I thought I’d re-share here.  Spicer was a duramax enthusiast who tested a bunch of aftermarket filters on a proper SAE test rig where the time was donated by another diesel enthusiast. 

 

TLDR: stick with AC Delco if you don’t want dirt in your engine.

 

http://www.billswebspace.com/AirFilterTest.htm

 

[1SLOW1500]

No just No....

[TRKLGND]

9 minutes ago, 1SLOW1500 said:

No just No....

No what?  If you disagree with the test results please share your reasoning.

[1SLOW1500]

The study is majorly off. what factory air box and truck is this in, oh it isn't. they strap it to a bench and blow 350cfm at it. Makes he wonder why any manufacture spends time and money with a air box. Then there is the debris is that the size that makes it in the air box or is that just the size they picked. At what size debris is it a issue with the engine or maf or anything? I mean most people don't think catch cans are needed or that oil and water in the intake manifold and on valves matters at all. But we are worried about  2.5 microns. Why? How about the performance test of airflow? I mean there is always a level on compromise. We need air and not dirt but how much and to what extent. 

If it was as easy as this Flow vs debris there wouldn't be billions in aftermarket product. Also have you ever seen and read up on High performance heads and seen there price. Even porting heads is a black art. A hose can flow fast or flow a lot. The balance per the need is the goal. Velocity vs. mass. 

People remove there turbo car air box or even filter at the track and see boost increase at lower rpms. Also the flat vs. cone vs larger cone filter. NO wait large cone with end cap also built in filter.... yes that is the most surface space .No screen for the win. 

But if we keep this to just stock trucks all the same and running a factory airbox in the factory location all that matters is what the need of the motor and the acceptable amount of debris is. then the final question at what cost of higher debris intake do I get more power? 3% is like splitting hairs with a axe. and again it is one second of a 10minute issue and also only works if all other variables are the same.  

The new truck need a recal. after a intake or filter change but again I bet more than 90% of people just bolt it up and drive. 

I was in a truck with a factory ac delco in the box. Truck had bumper and wheel well liner damage. Guy ran it through a few inches of water. Water shot straight into the box threw the filter and sent the piston out the side of the block. Same day we drove the buggy and my 4 wheeler into same pond no issues. those had K&N with prescreens as all sand buggies,bikes,truck,4wheels do no issues.

[TRKLGND]

It's called a "controlled environment".  You cannot have a fair test outside of a controlled environment.  It's actual science.  No black art.  
I agree that in everything there is a level of compromise needed.  What are the smallest particles we should be concerned with?  Not sure I have seen that data, with scientific evidence to back it up.  Gut feelings and guesses don't count. 

In a completely stock setup a performance filter will increase HP and TQ very slightly.  I have included a link as a reference.  Spoiler, it was about a 3% increase for the vehicle tested.  That doesn't mean it will be +3% for every vehicle.  Just this one.  YMMV!  Again, without knowing the particle size we should be concerned with, I have no idea if the 3% is worth the possibility of increased wear.

Further, a stock filter (clean) on a stock vehicle can flow more air than the engine can use.  Do the math.  Filter flow rates are published info and your displacement x RPM tells you how many CFM of air you need.  

 

[Black02Silverado]

16 hours ago, cit1991 said:

I’ve seen a bunch of posts on aftermarket air filters. I found a new site hosting the original Spicer air filter study done for the duramaxes. It was an important posting back in the day, so I thought I’d re-share here.  Spicer was a duramax enthusiast who tested a bunch of aftermarket filters on a proper SAE test rig where the time was donated by another diesel enthusiast. 

 

TLDR: stick with AC Delco if you don’t want dirt in your engine.

 

http://www.billswebspace.com/AirFilterTest.htm

 

This was done back in 2004 so it is outdated.  Technology has changed since then on filters in general.  Maybe someday when I win the Powerball or Megamillions I can actually do an independent study on current filters.    Problem is I need to play the lottery to win it.  LOL

[DirtyMarcus]

Yep, this testing is 15 years old.  ISO has changed their testing standards back in 2014 and filtration material for performance filter has improved dramatically.  This test is far outdated and should not even be considered valid data in 2019. 

 

 

[TRKLGND]

Would love to see new tests run.  Would also like to know what the smallest particles that we should be concerned with are.

Would be nice if someone with an ANSI.ORG membership could share the new standard info.  They want $185 for the PDF.