I was installing a boost gauge yesterday and I pulled the intercooler off.
Inside booth rubber boots on each end of the intercooler there was a significant amount of oil pooled up in the ridges. The outside the intercooler was clean and no signs of oil and both rubber boots were snug and tight. I'm assuming it came up from the supercharger? Is this bad??? Anything I should check further?








So I dug a little deeper and found that this is normal? (should have search before I posted) Can I delete this post?

Greatbear
Moderator :: Performance ModsJoin Date: Mar 2003
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Thanked 0 Times in 0 PostAny car engine, especially one with a turbo/supercharger has varying degrees of intake tract oiling.

The reason is actually quite simple. The engine has a PCV valve as well as a breather. The PCV valve as we all know works with intake manifold vacuum to positively ventilate crankcase vapors and pollutants. Simple, effective system. The breather is there to allow atmospheric-pressure air into the crankcase to make up for the volume of air and gasses taken out by the PCV system. The PCV valve on the MCS engine is plumbed into the intake manifold, so anything being picked up by it, including oil which has been aerosolized by the spinning engine internals, gets shuffled more or less right to the combustion chambers and is burned and exhausted, cleaned up by the catalysts and dumped into the atmosphere once again.

The problem arises when you go beyond part throttle and the engine vacuum no longer is there, and in the cases of turbo/supercharged engines, you have a positive pressure situation. All engines have a certain degree of blow-by. This blow-by is no longer able to make it's way through the PCV system because there is no more manifold vacuum and the valve is closed (and closed against boost pressure) This blowby pressure exits via the breather, taking with it the aerosolized oil. Since this is a pollutant, it must be routed to the intake tract where it joins incoming air being taken to the cylinders. The oil 'condenses' from the breather stream and coats the inside of the intaqke tract. In a naturally aspirated engine, there is not much to the intake tract, but the intercooled MCS has the supercharger, intercooler and all the ducting along the way. In the case of the intercooler, it works as an intercooler because of it's large internal and external surface area. This gives the oil a much better chance of settling out of the intake air stream and coating the inside of it.

You can eliminate the oil from the intake stream by simply disconnecting the breather (not the PCV valve) from the intake system and giving it free air. The problem is that you are now venting the blow-by gasses into the atmosphere. This is an emissions control violation, plus you will be smelling the blow-by gasses in and around your car as well and having the oily mist settling all around the open breather. Take off your oil cap and give it a sniff as a sample of the smell. Nasty.

An oil catch-can sits between the breather coming from the engine and the intake tract. It works by providing an area for the oily mist to settle out of the blow-by gasses. The bigger you can make the can, as well as provide internal baffling to make the a separation between the inlet and outlet, the better it works. A valve is often added to the bottom of the can to drain out the condensed oil.

 

You can edit your post, but IMO bringing this stuff back up is good. Lots of NAM newbies that bought a Gen1 and don't know too much about the cars.