Oil Catch Can

I installed an oil catch can with internal filter for my 99 NB. I use a quart of oil every 1K miles. I was thinking a lot the oil must have been lost in the "blow by". I was hopping that the oil catch can would catch a lot of this oil. To my surprise, it does catch oil but is only about 10% of the amount of oil I use. :-(

Another surprise is that it now rev up much faster and my butt dyno says I have extra several horses under the hood! I read something on the web that the blow by oil in effect lower the octane of the gas. It kind of make sense of what I have observed. For those looking to pick up a quick few horses for around $60, I highly recommend give the oil catch can a try. Of course, your mileage may be different.

I did some research before I bought my oil catch can. Make sure you get one with an internal baffle/filter etc. to slow down the flow to allow the oil to settle out into the can. Most of the FleeBay stuff are just a can with two nostrils and nothing inside to trap the oil. If you get those you have to mod it to work properly.

You don't "need" a baffle or filter as you call it, the point is that it is a fluid/air seperator. The liquid from the vapor condenses and drops to the bottom while the line that runs to your intake/ inlet draws air or smaller amounts of vapor. That being said, having a little dividing plate can help but it won't magically give you power. I run one because I end up with a decent bit of ethanol in my oil, catch can picks up a good deal of it and I dump it every oil change depending on how hard I was on it, occasionally earlier.
Anyways, something is better than nothing, baffle or not, especially on a car with a lot of blow by.

The other thing it does is keep a good portion of that oil form coating the inside of your intake manifold and depositing on the back of the intake valves and on the exposed parts of the fuel injectors. Over time it would also reduce the amount of carbon deposits in the cylinders themselves as you are not burning up the oil that is being drawn out from the crankcase via the PCV valve.

A catch can seems unnecessary for a normally aspirated motor on a street car as you are primarily dealing with vacuum and not pressure. I would think just a little filter attached to the valve cover would suffice if you don't want to recirculate the oil fumes. If the car is a race car where you are running extended periods of time at high RPM or you have forced induction you will build up pressure and a catch can would be beneficial. The oil is pressurized and a catch can is a good idea to catch the oil and vent the fumes.

Years ago I used a little filter on the valve cover on my CSP car. Had no problem until Miatamoto co-drove at an event. After one of his more flamboyant runs he pulls into the grid with smoke pouring out or the engine compartment. we popped the hood and found that oil was dripping out of that little filter and dropping on the exposed header below. Nice little flash fire ensued for which he will always be known for on this forum. A $25 catch can from a karting parts website solved the problem for me. Try as he might, he was never been able to start a fire after the catch can install.

dammit!

I just sold one for $20!

whatever......

JC, believe me, My butt dyno is telling me that it is worth the effort and every penny to put one on the NB! Even if it doesn't work for you, you can put everything back under 10 minutes and only out a few bucks! To me this is the cheapest extra horses mod that I have ever done! It is way cheaper than the catback and header mod on a NB. The main benefit is that it will keep the CEL away and keep your intake manifold clean. Just the money you save on Seafoam is enough to get the catch can! I agree that the filter mod is a fire hazard and is very bad for the environment to vent unburnt gas and oil vapor in the hot atmosphere.