Crankcase Vent and AIS

S

Snypar

New Member
Visit site
Anyone ever done or heard of taking the AIS hose and crank vent hoses that go into the airbox and connecting them together? I have a friend who is a great mechanic and owns a Busa and this is one of the mods on a Busa. Supposedly this creates a perfect match of pressure above and below the pistons increasing HP.
 
Snypar said:
Anyone ever done or heard of taking the AIS hose and crank vent hoses that go into the airbox and connecting them together? I have a friend who is a great mechanic and owns a Busa and this is one of the mods on a Busa. Supposedly this creates a perfect match of pressure above and below the pistons increasing HP.
Click to expand...

This sounds plausible as the crankcase typically is positive pressure and the AIS is a pump and sucks, creating negative pressure. But where are you dumping the vapor? The AIS output side dumps into the exhaust. Is this where you want the crankcase oil vapor to go? You have a choice, keep the AIS hooked to your exhaust or install one of those crankcase breathers from the local auto parts store to the output side of the AIS pump. I would suggest running a hose to the breather and putting it in a very low and in a remote location as the oil vapor will certainly coat anything around it with oil.

Maybe put it by the chain as a pre-oiler?!?!

I’m a gear head and I remember Nissan did the same thing to reduce the excessive crankcase pressure in its INDY Car Engines. Of course for their application it was a specific pump.

:wow:
 
Current Pro Stock Drag cars run dual vacum pumps to the crankcase to create an excess of negative pressure. They claim that it helps with piston ring sealing and to draw the piston down the bore. It is even starting to catch on in the slower drag racing classes.
 
I don't think the AIS on these bikes is actually a pump. Rather, it relies on vacuum from the exhaust to draw air in. That means the
"outlet" side actually is the header.
Drawing oil vapor into the exhaust seems like a bad idea. Eventually O2 sensors, catalytic converters (if you have them) and muffler packing would not be happy...

Although putting a breather on the crankcase may reduce intake temps, it does not help ring seal, or actually draw out vapors which include moisture.

This is why I haven't done anything with mine, but I am looking for a solution. Perhaps routing a hose and filter from the crankcase to a place that has at least minimal negative pressure?
 
You must log in or register to reply here.
Back
Top