Best Induction Kit / Set up

[Bean]

So using that 3.2 figure an area of 4 by 8 inches is enough for the stock engine, that's smaller than an oil filter. The oem filter is considerably larger.

[Project D]

1.6L @ 7500rpm, that's 6000L/min -> ~212cfm @ 100VE
(before someone ask: on a 4 stroke engine you need 720° or 2 revolutions to complete a cycle)
with 3.2cfm/in² you would need an area of 66 in², so a little bit over 8x8".

[jondee86]

comparing the airflow through one square inch of media is meaningless and
misleading. With the exception of a flat panel foam filter (if such a thing
exists) all air filters use some type of pleating or folding of the filter media.
This allows the active surface area of the filter to be many times the area
of the filter face area.

There are a range of factors that need to be considered when comparing
engine intake air filters. These include flow rate, initial resistance to airflow,
dirt holding capacity, particle capture efficiency, service life and how the
performance of the filter changes during its service life.

Research shows that the particle sizes that cause the most wear in engines
are in the 10-20 micron range. So it is critical that the filter have a high
efficiency in capturing particles in this range. Smaller particles tend to pass
straight through the engine and larger particles are more easily captured.

Testing for filter efficiency on capturing particles in the 10-20 micron range
can only be carried out in a properly equipped laboratory with sophisticated
measuring instruments and a supply of an ASTM standard test dust. Any
claims made by filter manufacturers that cannot be backed up by
independent laboratory testing should be taken with a grain of salt.

You could make a filter out of scotchbrite pad, oil it and use it on your off-
road racer, and it would collect a lot of dirt. It would have low resistance
which gave you better airflow for more performance and you could wash it
out and re-use it many times. Win all round you say But after a couple of
races your engine would be down on power... losing compression... oil very
dirty

Your engine just got 100,000 miles of wear in 500 miles of use because your
filter only captured the big lumps and a bit of fine dust on the oiled strands.
The wear causing particles passed straight through.

At the other end of the scale you could make a filter out of six layers of
used Covid surgical face masks. It would capture all the wear causing
particles but you would need a huge amount of filter surface area and the
filter would reduce the airflow to your engine as it loaded up with dirt.

What I am saying is that an automotive air filter has to meet a number of
goals. Low resistance and high efficiency do not go hand in hand.



The high efficiency HEPA filters used in the airconditioning systems for
operating theatres will usually have a low efficiency panel filter in front to
trap the largest particles, a second high efficiency filter to capture most of
the dust load, and then the HEPA filter only has to capture the very finest
micron size particles.

Most people looking for a filter upgrade will use one that fits in the available
space, looks good and is a nice colour. I chose ITG for my ITB's, Apexi for
single throttle and used oiled foam on my dirt bikes.

Cheers... jondee86

PS: Sunday morning under Covid lockdown... and since I once worked
selling air filters you get some rambling

[jondee86]

And just in case anyone is still wondering...



Have a read of this article... https://www.nicoclub.com/archives/kn-vs-oem-filter.html
... before putting your money down for the company with the largest
advertising budget I hadn't seen this before, and it makes the point
that I was trying to make, only with authority !!!!

Cheers... jondee86

[Project D]

I'm going to play devil's advocate and say 97% isn't THAT bad.
Also the test don't say what are the size of the particules in the 3% that has gone through the filter.

I had to dig, but I found this old article (the only one I remember ever reading about air filter)
http://www.mkiv.com/techarticles/filters...x.htmlbkbk

[jondee86]

Haha... that mkiv test was one of the things that made me to decide to
use Apexi filters

Now in the world of statistics 97% vs 99% may not seem like a lot of
difference, but if you look at these numbers in another way, the difference
is considerable. Let's say each filter is fed 100gms of dirt and one filter
collects 97gms and the other collects 99gms.

This means one passed 3gms and the other 1gm of dirt into the intake.
That's 3 times as much dirt, and since engine wear is more or less
proportional to the amount of dirt ingested by the engine, the engine with
the 97% efficient filter will wear out 3 times as fast.

Measuring the actual particle sizes that pass thru the filter requires a lot
more time and effort with high tech equipment, and is rarely done with
simple comparative testing. The larger the particles in the test dirt the
easier they are to filter out of the airstream. So it is safe to say that the
particles that pass thru the filter are at the finer ones.

However, it is also safe to say that all dirt that passes an intake air filter
in normal use will be bad for the engine... so more dirt equals more wear.

Research to find the particle size that is the most harmful to the engine is
a laboratory level experiment and is carried out using test dusts of very
specific particle sizes. ASTM filter test dusts are done with dusts that
contain a range of particle sizes representative of real world road dust.

I might add that I don't personally have a beef with K&N filters. I'm sure
they have applications in racing where car owners are prepared to trade
off higher engine wear against claimed power gains from a higher flowing
filter. It is (or was) a free world In fact many race engines run without
any filter at all for the same reason, but those engines will be pulled down
regularly for other reasons, so a bit of extra wear is not an issue.

Cheers... jondee86

[zenki]

I also have apexi. Affordable, ready to fit out of the box, decent quality.

[Rascal21]

When I bought a 4A-GE 16v Bluetop Bigport 3-rib that I swapped into a TA40 wagon, I went with a cheap mush-room filter and a Mercedes Benz intake hose that put the filter just about between radiator and coolant reservoir.
(forgive the other mess, it's an engine put in a car not meant for it, still working on the looks) looking c.a like this:


Which surprisingly had it give of as good an induction sound as I've heard on 16v single throttle's:

As far as dirt and all that goes.. this engine was pretty well worn in when I bought it in 2013 and still wears signs of having sat outside for longer than I have been alive (repainting 4A-GE means engine will blow, it's my only superstition).

Honestly I didnt even compression test it upon purchase, I slapped it in there about the summer 2014 I should think, when the 2T started making 3 different bad sounds at once and I've never put holes in blocks and didn't intend to start doing so either even if I'm not a fan of the engine (plus, never know when I might come across a 2T-G head).

I havent changed the filter (but I have been cleaning it, usually by taking out the insert mushroom and soaking it in diesel) and when I havent had the car under the knife for various mods to up the chassis potential and take a bit more advantage of the 4A-GE's very surprising abilities (everyone kept telling me it's just a dohc 4-banger with nothing special to it, I'd agree if throttle response and the exciting way it delivers what power it has, wasn't out of this world), I've been driving it for long treks, putting another 100-120k on that engine without any signs of more wear than it has, just prudent oil changes, the second the oil on the dipstick is starting to turn black = change, and apparently that's enough to keep these things alive regardless what filter is used.

To expand further, there's a guy on Youtube, Matt something, that uses his non-filtered 20v swapped ae86 mostly on the street too, as often as he can, and I sceptically asked him about the whole oil affair and he just uses some cheap Redline oil, changes it when it goes black, and has had no need to rebuild the engine yet (and he's been at it for more than a few years).

At the same time I have a friend who had a GT-S swapped AE85 from Japan, and he instantly killed the engine (Weber carbed high comp 16v 4A-GE) when hitting the dirt trap on a track day (that cost him 2x Weber rebuild kits, 2x cams, full set of valves, full set of bearings, rods, pistons, rings, rebore, honing, balancing, total about 11-12k Euro worth, which made it cheaper for him to do an F20C swap, which was what he did) so I wouldn't run an unfiltered intake, that's for sure!

[jondee86]

This is not a laboratory test but it shows what dirt in the intake air does
to an engine, and it only takes a few seconds...
https://www.youtube.com/watch?v=NwIjLECJmA8

Of course, unless you drive off road following a bunch of desert racers,
you have to wait a long time to get that same amount of dirt through your
engine, but eventually the result is much the same. I had a daily driver with
twin SU's and no filters and it was still going strong after five years.

It comes down to where you live, how often you are following other traffic,
the condition of the roads and how often it rains None the less, when I
invested >$5000 in a fully rebuilt engine it did not go anywhere until it had
an intake filter installed. What the filter does is make sure that the loss in
performance due to wear over time is minimised.

Cheers... jondee86

[decryphe]

Interesting video, result was expected but impressive none the less.