So what damage has occured to you N54 engine through using cotton gauge type filters?

pbondar

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May 30, 2020
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By now there have been many filtration tests that show that compared to full flow paper filters in a proper airbox that almost all (if not all) gauge type filters (K+N etc) let a large amount of fine particulate matter through the filters.

The question is: how much damage is this extra injested particulate matter doing to the engine and which parts?

I assume piston rings would suffer?

I assume changing your oil more often to remove particulate matter may help?

Maybe the heat of combustion destroys /renders ineffective particulate matter?

Maybe those particles don't do any damage?

I'm very keen to to hand onto my stock airbox and full flow paper filters but wonder how much loss of go I'll suffer once I go above the current MHD stage 2+ at 400 bhp crank onto the the TTE500 turbos to be fitted in the winter?

A brief test of no filter /airbox lid showed we moved from 400 bhp to 407 bhp.

All this on an E89 35is..

Comments pls?
 

Asmo

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Aug 23, 2020
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I had issues with collapsing inlets when using stock airbox on a friends car I was tuning.
 

NoGuru

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You need the extra airflow of the cones if you are going higher then 400or so HP.

I don't think you need to worry about filter particulates. I think you might get 190K miles instead of 200K as an example. Unless you are in a harsh environment like all dirt roads, then I would stick to stock airbox.
 
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iminhell1

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Jun 17, 2018
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The key to filtration is pressure drop.
Try catching a 100mph baseball. Odds are you'll want a glove.
Slow that baseball down to a reasonable speed and you can bare hand it.
Filtration is no different. All that surface area is to slow the incoming air, or put another way to grab air from the largest area possible.
So even with cones, you try to fit the largest ones you can. Bigger will filter better.
 

Torgus

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Nov 6, 2016
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Three ways to increase flow through a filter that I am aware of:

1) increase suction
2) increase filter area
3) decrease filter's PPM filtering ability to allow more particulates threw

Most cone style filters are a combo of 2 & 3 AFAIK.

Most cone filters do not filter out particulates as good as O&M from my reading/research.
 

TheObjectivist

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Three ways to increase flow through a filter that I am aware of:

1) increase suction
2) increase filter area
3) decrease filter's PPM filtering ability to allow more particulates threw

Most cone style filters are a combo of 2 & 3 AFAIK.

Most cone filters do not filter out particulates as good as O&M from my reading/research.

In your research, did you come to a conclusion as to which is the best compromise?

If so, do you have thoughts on which type is preferred for stock and tuned powers levels?
 

Torgus

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My vote is the largest filter you can fit is usually the best solution. Largest filtering area + they take a very long time it get dirty. Lots of surface area takes a long time to get contaminated. A filer has to be REALLY dirty to hurt performance. Like a lot worse than most people think.

On an N54 stock style twins this means moving from the stock drop in filter to dual cone filters. Alternative you could run the front turbo with a large cone filter and the rear turbo can use the factory air box or aftermarket box. Now the rear turbo has 2x if not more filter area, if you use a stock style filter(same size filter 1 less turbo drawing air through it), and you can put as large a cone filter on the front turbo as you want. Or huge cone filters on each. People make tiny and them make HUGE aftermarket cone filters.

Filters are cheap, I change & clean mine often. I have a spare so I put a clean one on and take off the dirty one, clean and reoil it(I have a single turbo, 1 filter). Just buy a spare set of DCI and have 1 ready to go at all times. Don't expect filters to pick up WHP or WTQ. If a filter makes it easier for the engine to breath it is usually because it does not do as good a job filtering as the stock media. You can't clean an oil a filter and put it back in the same day in most cases. Better to let it dry overnight or longer. Granted we don't have MAFs so less to be concerned about oil covering the MAF and fouling it. I would still wait a while. Also, don't over oil the filter after cleaning it!
 
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