What’s an Oil Catch Can?

So now that you have a performance motor you’re hearing about Oil Catch Cans and probably wondering what this is all about? Or maybe you know what they are but you’re not sure how to hook it up? No worries. This is a pretty common question and an easy one to answer.

On a car straight from the factory, they tend to re-route a lot of plumbing for environmental purposes, but this is not always the most efficient thing for the performance of your car. One of the things they reroute is the breather hose from your crank case. Inside the engine gases and sometimes a little oil will blow past a piston into the head of the engine. If this was not ventilated in some fashion, there would be a lot of pressure with nowhere to go. That’s not good. The factory solution routes these hoses using a one-way check valve back into the intake of your engine. So you’re feeding dirty, warmer air back into the engine. To make matters worse, there could be some oil residue in there and that’s going to gunk up things.

The aftermarket solution is to route those breather hoses to a catch can. The can itself can then be routed back into the intake, to atmosphere, or to your exhaust pipe to be sucked out. In a perfect world, you want some vacuum on the breather hoses to pull air and oil blowby out of the crankcase. So if you use a catch can and re-route it to the intake or to the exhaust then you achieve this result. However, it’s completely fine to just run both breather hoses to a catch can and then put a little air filter on the catch can and vent to atmosphere.

Oh, and in case you didn’t figure it out yet – the catch can accumulates the oil so that it doesn’t go back into the intake.

So here is the catch (no pun intended), you want to make sure that if you do re-route the catch can in some fashion that you are using one way check valves and that your catch can is baffled so that oil doesn’t go out once it has gone in. And remember, you’ll need to periodically empty the catch can. Once a month is usually about right for most builds, and it won’t be full.

Simple Catch Can
Nylon Braided Breather Hoses

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