Love Your Car? PCV Explained/ FRS Cusco Oil Catch Can Install

2015 Chevrolet Camaro Z/28
2015 Chevrolet Camaro Z/28

Are you bit critical, overly detailed, perhaps an automobile enthusiast? or maybe you just like to push your car’s limits and hit those RPM’s to red line. If you’re any of the above, or someone who just likes to read and learn about better ways to care for your car then this post is for you. We’ll Explain PCV and show you how to install a Cusco Oil Catch Can on a 2014 Scion FR-S.

Let’s start by explaining PCV (Positive Crankcase Ventilation). PCV is a way for your vehicles engine to do away with harmful gases and vapors that are also known as Blow-by. What do they blow-by you ask? They blow by your piston rings, illustrated on the bottom pic of a VW 2.8L VR6 engine. The green lines are where the piston rings are located. Those rings are made to form a seal between the crankcase (anything under the red line of the pic) and the combustion chamber (the cylinders in which your pistons oscillate, illustrated by purple lines), to prevent any harmful combustion gases from getting in the crankcase and any oil from the crankcase to get into your combustion chamber. There are small, but normal amount of gases the leak from the combustion chamber into the crankcase, also known as a blow-by.These gasses need to be vacuumed out or they will condense and mix with your oil causing a coffee colored sludge in your engine, and if any fuel that did not properly burn makes it to your crankcase it will dilute your oil losing its effectiveness.

VW vr6 motor

 Good news is, all of our cars starting from 1963 and on have the PCV system! Bad news is, it is not 100 percent effective…When the PCV system sucks the gasses out of the crankcase it also takes small amounts of oil with it, these gases and oil are vacuumed through hoses back into your intake manifold (illustrated by the yellow lines) which sucks clean air into your combustion chamber. This mixer of clean air, gasses, and oil are all burnt in the combustion chamber. The gasses, air, and oil once burnt are then forced out by your cars exhaust system.

Over time the oil that is carried through the PCV system and burned in the combustion chamber, starts to build up on your pistons, intake and exhaust valves, creating a black layer of burnt oil on the affected parts on the internals, and a film of oil on your intake manifold. ROBBING YOUR ENGINES HEALTHY PERFORMANCE AND HP!!!

The blow by gets worse, quicker, if you push your engine hard on a regular basis. Hint for anybody who does track days, autocross, strip runs, has a turbo or supercharged car, or even if your car has a high compression ratio (FR-S 12.5:1)

Well there is two solutions to this issue an AOS (Air Oil Separator) and or a Oil Catch Can If you haven’t figured it out by the name, these two products catch the oil and contaminants before they reach your combustion chamber.

(oil catch can in the picture)


This particular model is the Cusco Oil Catch Can for the Scion FR-S (Front engine Rear wheel Sport) and Subaru BRZ (Boxer engine Rear wheel Zenith).

The Difference between the two are quite simple, the AOS has an internal filtration system to efficiently separate the air and oil. Depending on the model of AOS you get, some need to be periodically checked and have the oil dumped out, other models have a hose that routes the oil back to the crankcase. The price, AOS, depending on the vehicle you drive and brand you prefer range from $160 – $300.

Oil Catch Cans have no filtration system, and catch the oil with its structured casing. These do have to be checked periodically and dumped out when enough oil collects. Newer cars (2010 and up) have very good PCV systems and only small amounts of blow-by and oil get into the intake manifold/ catch can, so you won’t see much build up, but will definitely see some over a long period of time. Catch can price range $100 – $200 dollars.

We have experience hooking up catch cans but not AOS, so we will show some pics on how to install this particular catch can. All we can say about the AOS installation is that they are harder, due to the fact that some drain oil back into the crankcase or oil pan, adding a extra hose or two to fiddle with.

“Cusco Oil Catch Can Installation FRS/BRZ, Inline with PCV Valve”

First the easy part, which I’m sure if you bought this particular Catch Can you’ll know it goes on the 2 black strut tower braces held by 4, bolts in the middle of the firewall , you only need to remove the two inside bolts. (Sorry for the bad pic) The bolts are directly behind the catch can, holding the blue bracket (provided in the box) that also holds the separate catch can in place.

Cusco Oil Catch Can

To get the catch can on the blue bracket all you do is slide it from right to left and tighten the screw behind  the bracket.

The few first steps are easy and anyone with a simple tool set would be able to do it. The tricky part is connecting the hoses, reason being, there are different ways of connecting them to get the same results.

We believe the way we are installing it, is the best way because it is directly in line with the PCV system. It is between the PCV valve which exerts the blow-by gases and the outlet hose which feeds the blow-by gases to the intake manifold.


The right yellow (hose was clear yellow due to oil) hose on the catch can is connected to the PCV outlet on the intake manifold. Imagine the blow-by travel from left to right.


The left yellow hose is connected to the PCV valve. We took multiple pictures so you can reference the PCV valves point on the engine.



As you can see the catch can is on the top left of the picture this can be used as a good reference point.

One small issue with Cuscos hose set up though, the hose provided by Cusco is too thick to firmly hug the PCV valve. We ran it with only the Cusco hose for one day and the hose slipped off, causing a CEL (Check Engine Light), the light goes away when the hose is reconnected.

   Here is the solution for that:


A filthy old hose….only kidding, underneath that black wrapping known as Stretch and Seal (I will explain the use for that later) is a 16 mm to 9 mm adapter, which can be bought at an Oreillys or Auto Zone, same goes for the 9 mm rubber hose. The adapter is so you can connect the clear 16 mm hose to a 9 mm hose that will hold on to that PCV very tightly and the hose won’t slip off. Stretch and seal (can be bought at Home Depot) as it says in the name is great for sealing. Small insignificant amounts of oil seep through the adapter and through the pores of the 9 mm rubber hose, and nobody wants a dirty engine bay…


There’s a picture of our clean non-greasy engine bay :D. When we first purchased the catch can and were looking to install it ourselves, we did not find a detailed install that shows exactly where each hose goes and why, like this one. So if you know a friend that owns a FR-S or BRZ and is considering a catch can, Please share this with them!

Link to Cusco Oil Catch Can, this is where we found it at a great competitive price,

If you like the post, have any questions, concerns, please comment below.

Leave a Reply

Your email address will not be published. Required fields are marked *