09-05-2012, 09:18 AM
It's just a positive crankcase ventilation system...
On an NA Petrol engine it's never really a problem, you don't have a 21:1 compression ratio and often 20lbs of boost also to give you some lovely high cylinder pressures... When you have those sorts of cylinder pressures, you get quite a lot leak past, inevitably ending in needing to go somewhere, on the stock induction system, it's perfect, it sucks it in through the turbo in a vacuum environment...
In the 50s engines used to just have a draft tube which essentially sucked out the gasses as you drove by having a pipe hanging down, but obviously as you know, if you pass air over a pipe, you get a vacuum - just like a carburetor venturi, but obviously that only works at speed...
The best thing you can do is to put it back in the engine, if you really are adamant you don't want breather gasses going back in (it's free fuel you know!!!) then point it at the floor or similar... The other way of doing it is to have a catch tank, but obviously there's two pipes in and out - you place one on the breather from the crankcase, and one back on the inlet to the turbo - that means you still have it under vacuum, but you'll catch the majority in your lovely catch tank...
On an NA Petrol engine it's never really a problem, you don't have a 21:1 compression ratio and often 20lbs of boost also to give you some lovely high cylinder pressures... When you have those sorts of cylinder pressures, you get quite a lot leak past, inevitably ending in needing to go somewhere, on the stock induction system, it's perfect, it sucks it in through the turbo in a vacuum environment...
In the 50s engines used to just have a draft tube which essentially sucked out the gasses as you drove by having a pipe hanging down, but obviously as you know, if you pass air over a pipe, you get a vacuum - just like a carburetor venturi, but obviously that only works at speed...
The best thing you can do is to put it back in the engine, if you really are adamant you don't want breather gasses going back in (it's free fuel you know!!!) then point it at the floor or similar... The other way of doing it is to have a catch tank, but obviously there's two pipes in and out - you place one on the breather from the crankcase, and one back on the inlet to the turbo - that means you still have it under vacuum, but you'll catch the majority in your lovely catch tank...
