Links to the popular Honda Pilot PreFilter Mod.

WHY would you want a air box and air filter that looks like this.


When you could have a air box and filter that looks like this driven the same distance in the same conditions as the above filter, your adding another layer of protection to your Engine and increasing flow, no need to remove the air box and protection from your Engine Honda installed a air box and filter more than large enough to supply air to even the CR500 modified Pilots the choke point is at the inlet to the air box, its more than adequate for a completely stock Pilot that is until the unprotected air filter in the air box starts to get dirty and their is a reduction is air flow.



Check it out here are others that did not have a prefilter that was on the same ride trip,
the chances of any dirt getting past your filter in the air box is much less when the filter
is CLEAN

New Pilot prefilter by hoser, http://www.pilotodyssey.com/PO/viewtopic.php?f=1&t=3211&start=0

Pilot Air Box Dual Inlet Mod http://www.pilotodyssey.com/PO/viewtopic.php?t=2306

CAFERCR35 - PRE-FILTERS http://www.pilotodyssey.com/PO/viewtopic.php?t=3758

Wiggins Prefilter Mod http://www.pilotodyssey.com/PO/viewtopic.php?f=1&t=1181&start=0

DC PreFilter Setup http://www.pilotodyssey.com/PO/viewtopic.php?t=1153

PilotNut Pre Filter Setup http://www.pilotodyssey.com/PO/viewtopic.php?f=1&t=2414&start=0

Afastcar Pre filter mod http://www.pilotodyssey.com/PO/viewtopic.php?f=1&t=4258

Pilot prefilter airbox lid by shoubadaba http://www.pilotodyssey.com/PO/viewtopic.php?f=4&t=12508

Mudbogger's Pre-filter follow-up for the Pilot http://www.pilotodyssey.com/PO/viewtopic.php?f=1&t=6328&p=54075

Fl350 air box dual prefilter http://www.pilotodyssey.com/PO/viewtopic.php?f=1&t=11029

Have a Polaris RZR you need a prefilter on it too http://www.pilotodyssey.com/PO/viewtopic.php?f=18&t=6528

Thank you Hoser for the great info.

What is everyone using for the hoses? Last time I think I used a wet dry vac hose,when I looked today the only size they had was 1 7/8" and that looked too small.Ive read all those links and didnt see what anyone said they were using

2 1/2 inch shop vac hose, you can buy at Home Depot, Menards, Lowes, just buy the standard shop vac replacement kit, cheap.
Dual air inlet lids are easy to modify, some of those Aussieduner lids are around if you look in fact.They worked pretty good.

(What triggered me was the fact that your first value was 12.5 square inches. That is ~ a square the size of 3" by 4".)

I used this site to refresh me on my circle formulas.
http://www.1728.com/diamform.htm

Circle Area = Pi x radius^2
Spoken: Pi times radius squared where Pi is 3.1415926

Radius is 1/2 of the diameter.

A recalc shows:

Value___Stock_____Hoser____Aussiedune
Radius___0.97______1.03_______0.95
Area ____2.956_____3.333______2.835
2 holes___N.A.______6.666______5.670____The Area times 2

Compared to Stock Units in Square inches Larger than stock
________Stock_____Hoser____Aussiedune
__________0________3.71_______2.71

Percentage wise: This is how I calculate it.
I divided the total area of Hoser or Aussiedunes openings by the
area of the stock opening and multiply by 100 for percentage.
This tells us that Hoser's is 225% The volume of stock.

________Stock_____Hoser______Aussiedune
__________0_______225.5%______191.8%

But if we take away the 100% volume for the stock opening we get how much larger each lid's dual openings combined as compared to stock.

________Stock_____Hoser______Aussiedune
__________0_______125.5%_______91.8%

So hoser's is 125% larger than stock. And Aussiedunes is 91.8%

As a side note since we're comparing two sets of volumes and the formulas are the same. The math reduces to a formula that doesn't even need Pi.

Test Radius Squared times 2 all divided by Stock Radius Squared will give us the same percentages.


Make sense? Do others compare percentages differently?

Another interesting fact would be to measure the air box air pressure on the same Engine across RPMs. Measure this for both lids and see that the stock has a much more negative pressure than the modified lids. And plot this as a comparison with a static atmospheric air pressure.

From my CO Pilot thread in my section, even got a picture of the exact kit I purchased:

Fabbed a dual air inlet bracket today for the ride at my friends muffler shop.Using his tubing expander I was able to size the OD of the tubing to accomendate the K&N RU-0620 Filters I purchased(see Hosers tech pages for the prefilter thread) -I purchased some 2 1/2 iinch OD shop vac (rigid) from home depot, inside the ends are a perfect fit for the dual air box inlet which AUSSIEDUNER had made for the group sometime back in the day.The bracket was a easy make, piece of flatstock and 2 3' pieces of piep expanded at the inside end to fit the filters.I will paint and clear it, install as soon as I get the filters from K&N.HERES A PICTURE OF THE BRACKET WE MADE TODAY

Ok thanks
I was at home depot today and the only ridgid vac replacement set they had was 1 7/8,so don't know if they stopped carrying the other or they are just out

Here's a simpler way I did mine. I call mine the sewer way of doing it. I used a 3 1/2" sewer ABS pipe coupling, a 45 degree elbow and the K&N filter with prefilter. So far it's held up well and I did the modification about 2 years ago. I was concerned their was too much weight on the actual filter box lid. The plastic is thin and I didn't know whether I'd crack the lid from continuous vibration during riding. Happy to say no problems and the air box lid is holding up pretty well.

Good idea but I cant do it.I had a choice of 6 lids and they were all already modified.I chose the one that already had 2 tubes glued in the top.

that's ok you need a setup that is resistant to riding in the rain and for muddy conditions anyways with the big filter on the box setup your filter in the air box is as vulnerable as a cloth suspension seat in the rain/mud, run my type setup you can run in all the rain/mud you want and it does not migrate to the air box, no fear of getting caught in the rain while out on a ride, no worries of blasting through a deep water hole you didnt see coming on the trail.

With two holes on the lid, you don't have a choice. Per hoser's comment, it might help having the prefilters higher if you go after every mud or water hole. Mud and rain will get everywhere regardless.

The whole point of doing this is 1. Getting more air in the intake and 2. doing it safely without the Engine inhaling a bunch of crap. The prefilter is designed to be trashed and take all the abuse before anything gets to the main filter.

I think hoser's orginal idea works well but you have to fabricate a bracket to mount the prefilters to the upper roll cage. I'm not a fabricator so the sewer method has worked well for me if your able to use an unmolested lid. Also, I have ridden my pilot in some crappy mud/water conditions and filter does get hit but not horribly bad because it's above the fender.

You can take a piece of sheet metal and patch the top of any air box then cut the hole you want in the metal and use what ever setup you want, you can even swap from the single filter setup like yours to a double filter setup.

My setup has proven many times that it flows more than enough air, three times it ran right along side three different ATV Racing CR500 race ported desert filter Pilots, 2 of the 2 was running the 41mm carbs too.

These engines are not gulping as much air a you might think.

sewer pipe lol

Let me correct my first post on the thread: Dave-Co initially came up with term "sewer pipe". Thanks buddy!

Here is what I bought in the past