Saikou Michi OCC (oil catch can)

[boom]

So I had ordered a SM can a couple of days before the review posted here:http://www.e90post.com/forums/showth...t=saikou+michi

Based on the thread, I changed my order from a standard stage 1 OCC to the n54 specific can. I installed it when it arrived but was not thrilled with the hose diameter and fitment issues caused by the size of the can and the sharp bends needed to make the hose work.

I emailed my frustration to Saikou Michi and they were more than accommodating. They wanted to help and had developed that can based on the instructions that the OP in that thread gave them. It turns out the guy that wrote the review sold his setup a couple of days later and I believe is selling his car.

I emailed them a few suggestions on what I would do differently and they offered to send me a replacement based on that spec. It only took a week or so but with the holidays, travel, and me relocating I just got it installed today. I'm thrilled with the result.

I suggested moving to 1/2" hose as it would survive the bends without crimping. I also suggested that the stage 1 OCC diameter was more appropriate given the tight space. It fits perfectly.

Here are few pix of the install.

The can: Stage 1 OCC with 1/2" barbs and a 45 deg offset


I bought the riss racing hose kit originally and used the intake line setup. IIRC its a 1" to 1/2" reducer using 1" hose to connect the 1/2" line to the stock intake port.


The PCV valve is connected to the 1/2" hose using a very small piece of 3/4" hose to a 1/2" barb elbow with 1/2" pipe thread. The shorter the 3/4" hose the better to avoid hitting the firewall with the elbow or bending the 1/2" hose.




Here are some pix showing the lines assembled and the tightness of the space.





The finished product:





The can fits nicely in the space, doesn't rub, and is easily removed with the 10mm nut on the fender well. The hose bends are nice and smooth with no crimps. I'm very happy with the new setup and have nothing but praise for Saikou Michi. Their cans are top notch and not too expensive. Their customer service is second to none.

[Sticky]

You are by far the most informative member posting the best content I have seen thus far.

[Laloosh]

Like i said on e90. I'm running the same catch can, with the stock dimension hoses. Your are castrating the pvc system by going so small. The stock 1in and 3/4inch hose fits just fine, you just routed it wrong the first time.

[prasanth5]

Dear friends, what is the purpose of installing this oil catch can? Is it worthwhile to invest some money on its installation.?

[boom]

Dear friends, what is the purpose of installing this oil catch can? Is it worthwhile to invest some money on its installation.?

The factory PCV allows oil to pass in to the inlet pipe. The oil will coat everything, your FMIC, your charge pipe, throttle body, intake manifold, valves, etc. The catch can captures the oil preventing it from depositing on everything but still allowing the PCV system to breathe.

[Laloosh]

oil will also lower the octane rating of gas. So if you are running an agressive tune on piss poor 91 octane, without a catch can, chances are your timing curve looks like the rockies.

[saikyo]

I really need to get this and replace my RR catch can, what a POS.

[oddjob2021]

i have a RR catch can, just for reference, with no issues, I also have their first series of downpipes, no fitment issues.

[Sticky]

oil will also lower the octane rating of gas. So if you are running an agressive tune on piss poor 91 octane, without a catch can, chances are your timing curve looks like the rockies.

So you are saying the oil gets into your fuel system somehow? Or into the motor through the throttle body? Is this correct?

What the hell is up with the stock design then?

[boom]

the pcv is recirculated through the intake. Because our cars are DI the oil travels through the head and past the valves into the cylinder without mixing with fuel. On a port fuel injected car the gas would wash over the valves and the oil would dissolve and burn with the fuel. With DI the injectors are in the combustion chamber and the oil coats everything in the head and can go into the cylinder. Another disadvantage with DI is exhaust gas regeneration. BMW deals with sooty egr by running lean. They can do this because they pulse the injectors 3 times per cycle at ~3000psi. By comparison, the VW and mazda cars run around 1800 psi and only pulse once per cycle. Because the fuel doesn't completely atomize in those applications, they don't get the cooling effects we do and consequently have to run richer to prevent knock. Rich = soot. Soot + egr + oily pcv = carbon deposits on the head and valves.

[Sticky]

the pcv is recirculated through the intake. Because our cars are DI the oil travels through the head and past the valves into the cylinder without mixing with fuel. On a port fuel injected car the gas would wash over the valves and the oil would dissolve and burn with the fuel. With DI the injectors are in the combustion chamber and the oil coats everything in the head and can go into the cylinder. Another disadvantage with DI is exhaust gas regeneration. BMW deals with sooty egr by running lean. They can do this because they pulse the injectors 3 times per cycle at ~3000psi. By comparison, the VW and mazda cars run around 1800 psi and only pulse once per cycle. Because the fuel doesn't completely atomize in those applications, they don't get the cooling effects we do and consequently have to run richer to prevent knock. Rich = soot. Soot + egr + oily pcv = carbon deposits on the head and valves.

Well, I thought running lean was due to the cylinder cooling effect of the DI which allows it without detonation, which is where part of the MPG bump comes from.

Since the cars run a bit lean (not under WOT) the carbon build up is not as big of an issue as with the 4.2 DI Audi V8's, correct?

[boom]

They actually run VERY lean under WOT - high 13s stock AFR at redline. The carbon buildup in the head results from the PCV and EGR. The catch can gets the PCV taken care of. I'd love it if someone could fix the egr issue.

[Sticky]

They actually run VERY lean under WOT - high 13s stock AFR at redline. The carbon buildup in the head results from the PCV and EGR. The catch can gets the PCV taken care of. I'd love it if someone could fix the egr issue.

Good stuf... high 13's at redline? Damn...

[boom]

I know. It's crazy how lean it can run stock. I think the lean WOT results in extremely high EGTs which is why a lot of the aftermarket cats fail so quickly.

[MSpiredM3]

Inlet and outlet are too small imo

[boom]

The inlet and outlet are 1/2". Stock is 3/4" but the space is so cramped behind the head where the PCV exits that a hose that size can not make the bend. As it is I'm using a 90 deg plastic bend and am still not thrilled about how much the 1/2" hose has to turn. FBI's catch can has this cool expansion fitting that address the angle beautifully. As far as outlet/inlet size is concerned, I don't think it's an issue. The RR can has 3/8" nipples and guys have been running those forever and collecting a fair amount of oil/sludge.