Must for racers and high powered set ups! Nice one
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.Frankly, the cans i have seen are insanely priced for a cup of aluminum, a cap, and sintered filter....
After reading this im in for the sexy high end one1.75 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).
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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...
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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.
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?By blanking the inlets and keeping PCV you loose the vacuum and system doesn't work properly.
Lars, EVERYTHING you do is SEXY Buddy! lolAfter reading this im in for the sexy high end one
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