Hey guys, I'm hoping someone can explain this to me. I'm running APR Stage II software so i peak at around 21-22lbs on a stock setup. When i removed my air box and ran the car with the MAF attached to the turbo hose I lost 5 lbs. It didn't make sense to me. Can anyone explain this? Also, what does the aux hose leading from the air box do anyway?

Thanks

 

The small hose from the air box is for your Secondary Air Injection pump.

Odd, you shouldn't lose boost just because you removed the air box. Now if your maf plug came loose your boost could drop since at that point your running mafless.

 

maybe you knocked another hose loose in the process and have a leak causing this issue

or you don't have a nice seal on the maf with the filter and unmetered air coming in, but that shouldn't cause a drop, but maybe?

 

Sorry for the late response, Ill check it out soon but the temperature dropped 50 degrees today and it snowed... Odd. But what does the Secondary Air Injection pump do anyway? Just looking for knowledge. I did however leave the flange that connects to the MAF off that's located inside the airbox. Would that make a difference?

 

It pumps air into the back of the head on the exhaust side, that air then flows over the back side of the exhaust valves to act like a vacuum and also increases the air ratio in the exhaust gas which also causes the car to right richer during that time.

 

Thats a mouthful. Thank you though.

 

so does this mean everyone (stock and upgraded turbos) is stuck with constant rich gas mixtures? cause this fuel mixture seems to be a problem to a lot of people including me, but cant find a fix.