Crankcase Filter Modification

Crankcase Filter Modification

Began: November 18, 2001

Reason: I had already started playing around with a primitive ram air system and was about to do the air box mod which would remove the hose from the air box to the crankcase ventilation, so I needed something to put on the crankcase ventilation connection.

Objective: Remove the air box to crankcase ventilation hose and replace the hose with a K&N Breather Filter.

Warning: This mod may not be for everyone. If you live in very cold climates you may have problems, this mod prolongs the amount of time it takes your engine to heat up. This mod is not a permanent modification to your vehicle, in fact it is easily reversible.

Tools and Parts Needed: At maximum 3' of 5/8" radiator hose, a K&N breather filter, a flat head screw driver (preferable a short one), and a few rags.

The Project: The mod is very simple and should take about 5 to 10 minutes from beginning to end. You will be removing the air box to crankcase ventilation hose and replacing it with a hose that is connected to a K&N Breather Filter.

First remove the air box from on top of the throttle body. Connected to the air box will be a short hose (approximately 6 inches long) that connects to the driver's side of the valve cover. This is the air box to the crankcase ventilation hose (what a long name for such a short hose), remove it from both the air box and the valve cover (the crankcase ventilation).

Take the 5/8" radiator hose, stick one end of it in your K&N breather filter and tighten the worm gear clamp on the breather filter tight enough so that the hose can not be pulled out, but not tight enough to deform the circular hose. Place the breather filter anywhere you want under the hood of your car. I initially placed it in front of the battery, later when I made the quad ram air the breather filter had its own ram scoop, but anywhere under the hood will do (I prefer colder air, so a cooler location is best, and one away from moving parts, like the drive accessories, is also nice). Once you have found a suitable location for the breather filter, cut the 5/8" radiator hose to the proper length and connect it to the crankcase vent (as seen in the picture below).

You've now completed the crankcase filter modification, congratulations you've earned yourself somewhere between 1.4% to 3.8% more horsepower (that's approximately 1.3 to 3.5 hp on a bone stock engine, more if you're done some other mods).

Your engine will warm up a bit slower, so this mod may be a problem for drivers who take frequent short trips. The mod will keep your engine a bit cooler, especially with the use of the quad ram air in conjunction with this mod. Since the air box to crankcase ventilation hose is now removed oil fumes (yes, even with the filter some could get up into your air box) can not get into your intake (oil fumes decrease your fuel octane), so this will in effect increase your effective fuel octane level. Mainly it will keep nasty oil from coating your air filter and throttle body (both of which will decrease air flow and performance). The cooler crankcase will yield a little better thermal efficiency, and you will get a slightly cooler intake charge (no hot vent from the crankcase feeding directly into your air box anymore).

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