Ok, then tell Bill to PM me too.

 

Sorry for the guys but it's somewhat related to fuel pumps. Cavitation, at least how I learned it in school is when a impeller/propeller spins at too high a revolution and causes an extreme low pressure point on the back sides of the blades, at which point the water/fluid flash boils. (there are two ways to boil a fluid, either heat it to it's boiling point or lower the pressure until it flash boils) As soon as the fluid boils, tiny air bubbles appear and when they make contact with a solid object it IMPLODES, taking a piece of that object with it. That is why on improperly sized propellers you will notice alot of "pitting" on the low pressure sides of the blades. It's hard to hear on small pumps and propellers but on large ones such as on ships and in Hydro electric dam's cavitation sounds like a million tiny explosions against the volute casing/surface of the impeller/propeller. Gone unchecked it will destroy a pump or propeller/impeller and depending on the fluid could create a serious problem. I have never heard of this happening with fuel pumps but thought I would share the definition of a cavitating pump/impeller.
When a pump starts sucking air it's called loosing vacuum.

 

That's exactly what it is. Get a pump that won't cavitate and you'll be a rich man. Or a submarine engineer.

 

ok say i want to convert to return style and i used the stock feed line which i gather from ls1tech is about a -6 line could i use a -4 return? i ask because i have like 20 feet of -4 in my shed. and what about the evap does it just stay there?