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Standard more cost effective oil catch can solution / top end, baffled, oil catch can?

  • Standard, more cost effective, I want to spend the rest of the money on other things than my 4C

  • Top end, quality is what matters, I only choose the best for my 4C

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Discussion Starter #1 (Edited)
Hello gentlemen,

With about 40.000km on our DFI engine and quite an extensive tracking, it is more than about time to finally clean up the engine breathing capabilities and get rid of carbon build up on valves and oily IC and intake manifold.

I'd kindly ask you for your guidance. I'm in the final stage of releasing our oil catch can system and there are two options. We can go with top end baffled catch can or a standard non baffled catch can. The standard one, will remove about 90% of dirty oily vapors and provide a clean engine to the engine PCV. The more expensive - baffled catch can will remove additional 5-10%, let's say 98%. It's just a guess and some test with water vapors. For 4C engine we need two oil catch cans to make system work correctly, so with all the brackets, piping, clamps and two oil catch cans the complete system will come with a price penalty. So the question is. Would you go with standard more cost effective solution, or would you go with top end, baffled system, regardless of the cost. The good thing is that system will last the lifetime and the filters inside the catch cans are washable and replaceable.

I know the way I'll go, but I'm still curious what would you guys choose?

And don't worry, the poll is anonymous. :cool:

Budget variant... 😁
Finsihed1.JPG

Proper variant... 🥰
MMBCC-CF_1_6.png
 

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Must for racers and high powered set ups! Nice one
 

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Proper variant......
 

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I wouldn't like a plastic catch can in the high temperature engine bay (or glass)... Frankly, the cans i have seen are insanely priced for a cup of aluminum, a cap, and sintered filter....
 
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Frankly, the cans i have seen are insanely priced for a cup of aluminum, a cap, and sintered filter....
Absolutely agree, "proper" cans are way overpriced. I got a decent deal on a slightly used Moroso for my supercharged Miata and I'm glad I made the effort to install it - surprising how much crap ends up in there. I'd like to have cans for my 4C but I'm guessing it won't be a cheap proposition.
 

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If, as it appears you're headed, the final product incorporates a baffled Mishimoto can, you could offer two excellent choices:
  • Top End, Baffled System with Carbon Bling, or
  • Equally Top End Baffled System without Bling (for half the cost)
I have the latter on a BRZ and thought it was overpriced at $200 for the complete kit until I emptied the can for the first time. Yikes!

Would be interesting to send that crap off for analysis. Whatever it is I'm glad the catch can stops it from recirculating through my boxer's intake and I'd love to have one (or two) to prevent same on the 4C.

Godspeed on this project!
 

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I’m definitely in for a proper catch can.

I had a dual can Moroso on my sti tthat did an awesome job and would love to have something similar for the 4c.
 

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Showing my lack of comprehension on how the breather system works, why do you need two catch tanks?
And, it looks like you're feeding fumes back into the intake/inlet system, why not vent to atmosphere?
 

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Discussion Starter #11 (Edited)
1.75 Tbi engine has dual PCV venting system. the PCV (positive crankcase ventilation) is a system that allows the breathing of the crankcase. While the engine is rotating there is some pressure generated within the crankcase and the head. This air has to circulate otherwise the pressure would build up and push the oil out of the engine either through the oil pan or any other path it could find. That's why the PCV is needed. The PCV collects the oily fumes and vapors and separates the oil from air and then returns the partially cleaned air back to the intake path where this oily air then mixes with fresh air and it goes through another combustion process. This provides maintenance free and emission friendly system. All good.

The red circle (stock PCV) is where the oily fumes from the head are collected and then go in two directions (green circle). Part of oily fumes enter the intake right after the throttle body (one on the lower left corner) and other part of oily fumes enter the intake before the turbo compressor (one on the upper right corner).

stock.jpg


So what's the bad part? The bad thing is that this oily air is messing up your entire engine, steadily but surely. The entire intake path from turbo onward is getting oily and dirty. It starts right after the turbo compressor where the dirty oily air enter the intake system and as mentioned above another entering point is right after the intake throttle body. That's why you find oily charge piping, intercooler, intake, throttle body etc. Not good. The second and even more serious issue is a concern on DI (direct injection engines / spraying fuel right in to the cylinder). Why? The dirty and oily air from the intake travels through intake valves and exits through the exhaust valves. The exhaust valves are very hot, so most of the oily and dirty air burns, but the intake valves are not so hot and this oily and dirty air turns into carbon deposits and sits on the valves and inlet ports of the head and it is messing up your head internals. Depending on the style of your driving and the oils you are using your engine DI starts to build up carbon deposits from the day 1 you turn on the engine. You slowly start loosing engine performance (head flow starts do decrease as the carbon build up takes the volume) and in worst case scenario your head gets filled up with carbon deposits to the point, that the valves cannot operate properly anymore and this can cause a complete engine failure. There is also a chance, that a chunk of thsi carbon build up tears off and drops in to the cylinder jamming piston rings. That's how a carbon build up looks...

Intake_valves.jpg

Older non DI engines were not so delicate using stock PCV, because the fuel is not sprayed in to the cylinder but before the intake valves, so the fuel is cleaning the dirty valves. Especially if you drive the engine hard and it is running a bit rich, you don't have to worry about carbon build up. The reason for manufacturers to switch from non DI to DI engines is of course fuel efficiency as DI engines are more efficient. The latest engines from some manufacturers, for example Ford are using combined technology of DI and non DI system that can spray the gas prior to the valve or right in to the cylinder, which makes the engine immune to the carbon build up.

So what can I do? The only solution is to install oil catch cans. These will prevent the dirty and oily air to enter the intake path. Instead, the oil catch cans will collect this dirty oil. The downside is that you will have to empty the catch cans every now and then.The hardcore solution would be to have this dirty oil air routed in to the exhaust system which would effectivly get rid of it, but driving behind you would smell like an old car worn out car and there could be a problem at the emission tests. So catching this dirty and oily air in to the catch can is the solution we are looking for. Your engine will now also produce dirty oil which will have to be wasted instead of getting recycled through the combustion process, so yes you are producing more pollution. If you don't want to take this route, then the most you can do, is postpone the carbon build up issue by using only high quality oils designed for DI engines, changing the oil frequently and every now and then adding some valve cleaning additives.

Some engines are more prone to carbon build up than others. I haven't taken a look into the 4C carbon build up yet, but by the amount of oil I have in my intake paths I'd say that PCV is letting quite a lot of oil through the engine.
 

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Thank you for that detailed explanation Rudi. I have now dismantled the PCV and got a better understanding of its operation (I guess that's a nrv on top of the inlet manifold which closes under boost pressure).
But, why not blank off the breather inlets into the manifold and the turbo and, using old school technology, vent to air through a simple catch tank. Yes, there's an environmental issue but I'm thinking of motorsport applications, not road use.
Referring back to your original post Rudi, I'd use the simple low cost system. 90% removal is still a huge gain. Having seen the oil residue in the intercooler, hoses and inlet manifold on a 11000 mile engine any cost is worthwhile.
 

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1.75 Tbi engine has dual PCV venting system. the PCV (positive crankcase ventilation) is a system that allows the breathing of the crankcase. While the engine is rotating there is some pressure generated within the crankcase and the head. This air has to circulate otherwise the pressure would build up and push the oil out of the engine either through the oil pan or any other path it could find. That's why the PCV is needed. The PCV collects the oily fumes and vapors and separates the oil from air and then returns the partially cleaned air back to the intake path where this oily air then mixes with fresh air and it goes through another combustion process. This provides maintenance free and emission friendly system. All good.

The red circle (stock PCV) is where the oily fumes from the head are collected and then go in two directions (green circle). Part of oily fumes enter the intake right after the throttle body (one on the lower left corner) and other part of oily fumes enter the intake before the turbo compressor (one on the upper right corner).

View attachment 106162


So what's the bad part? The bad thing is that this oily air is messing up your entire engine, steadily but surely. The entire intake path from turbo onward is getting oily and dirty. It starts right after the turbo compressor where the dirty oily air enter the intake system and as mentioned above another entering point is right after the intake throttle body. That's why you find oily charge piping, intercooler, intake, throttle body etc. Not good. The second and even more serious issue is a concern on DI (direct injection engines / spraying fuel right in to the cylinder). Why? The dirty and oily air from the intake travels through intake valves and exits through the exhaust valves. The exhaust valves are very hot, so most of the oily and dirty air burns, but the intake valves are not so hot and this oily and dirty air turns into carbon deposits and sits on the valves and inlet ports of the head and it is messing up your head internals. Depending on the style of your driving and the oils you are using your engine DI starts to build up carbon deposits from the day 1 you turn on the engine. You slowly start loosing engine performance (head flow starts do decrease as the carbon build up takes the volume) and in worst case scenario your head gets filled up with carbon deposits to the point, that the valves cannot operate properly anymore and this can cause a complete engine failure. There is also a chance, that a chunk of thsi carbon build up tears off and drops in to the cylinder jamming piston rings. That's how a carbon build up looks...

View attachment 106163

Older non DI engines were not so delicate using stock PCV, because the fuel is not sprayed in to the cylinder but before the intake valves, so the fuel is cleaning the dirty valves. Especially if you drive the engine hard and it is running a bit rich, you don't have to worry about carbon build up. The reason for manufacturers to switch from non DI to DI engines is of course fuel efficiency as DI engines are more efficient. The latest engines from some manufacturers, for example Ford are using combined technology of DI and non DI system that can spray the gas prior to the valve or right in to the cylinder, which makes the engine immune to the carbon build up.

So what can I do? The only solution is to install oil catch cans. These will prevent the dirty and oily air to enter the intake path. Instead, the oil catch cans will collect this dirty oil. The downside is that you will have to empty the catch cans every now and then.The hardcore solution would be to have this dirty oil air routed in to the exhaust system which would effectivly get rid of it, but driving behind you would smell like an old car worn out car and there could be a problem at the emission tests. So catching this dirty and oily air in to the catch can is the solution we are looking for. Your engine will now also produce dirty oil which will have to be wasted instead of getting recycled through the combustion process, so yes you are producing more pollution. If you don't want to take this route, then the most you can do, is postpone the carbon build up issue by using only high quality oils designed for DI engines, changing the oil frequently and every now and then adding some valve cleaning additives.

Some engines are more prone to carbon build up than others. I haven't taken a look into the 4C carbon build up yet, but by the amount of oil I have in my intake paths I'd say that PCV is letting quite a lot of oil through the engine.
After reading this im in for the sexy high end one

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By blanking the inlets and keeping PCV you loose the vacuum and system doesn't work properly.
I would like to thank you too for the explanation on the catch cans. My question is how and where do you lose the vacuum if you vent the PCV to atmosphere?
 
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