The engine I swapped into my 80 series had a road draft tube. On a cabover Mitsubishi, a road draft tube isn't so much of a concern, but on a Land-Cruiser where the engine is out front, it causes the truck to smell like oil and wafts smoke into the underhood area. I want to deal with this as I can't stand the smell and smoke.
There are three options I can see, all of them have their advantages and disadvantages.
1 - Route vent into airbox, before air filter (on atmospheric side). This involves running a hose from the valve cover to the air filter housing. I'd have to weld on a bung of some sort. Easy, but results in oily mess in the airbox, and a gummed up air filter, unless I use a catch can.
2 - Route down, and into exhaust via a slash cut pipe. The theory is that by introducing a slash cut pipe into the exhaust, a venturi is created by the exhaust gases, which pulls a vacuum on the crankcase. The fumes go out the tailpipe and, due to the heat of the exhaust, are likely partially dissipated. Due to the underhood arrangement, this is the cleanest option, and requires no maintenance. The intercooler and turbo stay clean. Downside is that if there is too much backpressure, it can pressurize the crankcase. If I was using straight through exhaust, I could see this being the best option, but with a stock muffler I think there might be a bit of back pressure.
3 - Vent into airbox post filter. This is not good as the turbo can pull a vacuum between the turbo and the filter, which pulls a vacuum on the crankcase, which can be hard on seals, etc. I have a hard time seeing more than a couple of inches vacuum between a filter and engine, and a modern PCV system on a gasser pulls a vacuum anyways, without effect. The upside is that it would keep the air filter oil-free, downsides as above. This is probably the cleanest option as the 93-94 FZJ80 already has the bung for the hose, which was for the air injection system.
Not sure what the best option is. I like the simplicity of the exhaust exit, and it would reduce the amount of underhood plumbing, but the other options are also more environmentally friendly.
There are three options I can see, all of them have their advantages and disadvantages.
1 - Route vent into airbox, before air filter (on atmospheric side). This involves running a hose from the valve cover to the air filter housing. I'd have to weld on a bung of some sort. Easy, but results in oily mess in the airbox, and a gummed up air filter, unless I use a catch can.
2 - Route down, and into exhaust via a slash cut pipe. The theory is that by introducing a slash cut pipe into the exhaust, a venturi is created by the exhaust gases, which pulls a vacuum on the crankcase. The fumes go out the tailpipe and, due to the heat of the exhaust, are likely partially dissipated. Due to the underhood arrangement, this is the cleanest option, and requires no maintenance. The intercooler and turbo stay clean. Downside is that if there is too much backpressure, it can pressurize the crankcase. If I was using straight through exhaust, I could see this being the best option, but with a stock muffler I think there might be a bit of back pressure.
3 - Vent into airbox post filter. This is not good as the turbo can pull a vacuum between the turbo and the filter, which pulls a vacuum on the crankcase, which can be hard on seals, etc. I have a hard time seeing more than a couple of inches vacuum between a filter and engine, and a modern PCV system on a gasser pulls a vacuum anyways, without effect. The upside is that it would keep the air filter oil-free, downsides as above. This is probably the cleanest option as the 93-94 FZJ80 already has the bung for the hose, which was for the air injection system.
Not sure what the best option is. I like the simplicity of the exhaust exit, and it would reduce the amount of underhood plumbing, but the other options are also more environmentally friendly.
