okay so your standing at the front of the car looking at the engine. on the left side of the engine that hose that goes down and underneath the car to a vent/intake port thing. wut is it? can you just eliminate the hose and just replace with a small aftermarket filter?

 

You mean the silencer for the ACV dump? You typically end up with some strange noises at random times if you take that off while the air pump is still connected.

 

i have no idea what it is. its a hose that goes down heads through what looks like a filter than goes to a vent thing in the front bumper/lip. is it necessary? im doing a tii swap and just trying to clean up the engine bay cause its my first swap

 

like he said, it is the silencer, you can take it off if you like.

 

if you remove it you must remove the acv and block it and remove the air pump or when you hook your motor up you'll have no back pressure to spool up.

 

What? The dumped through the silencer has nothing to do with the engine itself. Under ~3500 rpm & not at WOT, the relief valve keeps this path closed so that air pump air can make its way to the exhaust ports and main cat. Above 3500 rpm, the relief valve dumps all air being pumped by the air pump out the silencer. You can take it off and nothing will happen except you'll now get odd noises above 3500 rpm.

The ACV and air pump have nothing to do with exhaust back pressure.

 

I'm not on here talkin outta my ***. However I'm not even mad cause I said the same thing. But my car disagrees. My car would severly suffer power loss above 3500 rpm. No boost because it somehow diconnected. Everytime it popped off,no power, fix it and I was flyin again. Soo.. I say this from experience

 

thanks! whats the acv? so you can just disconect it and plug it? i already got rid of my air pump....

 

are you sure you're not thinking of the vacuum line on the acv that's routed to your pressure sensor over the dump pipe.

 

air control valve. it's what your airpump was connected to...

 

The ONLY way this could happen is if your check valve between the ACV and the LIM is wasted or completely missing. If the check valve allows exhaust gas to flow back into the ACV, then it will vent it out through the silencer passageway above 3500 rpm. Even then, I still can't see it being any more than a minor drain on spool time of a turbo since the only difference between having the silencer tube and not having it is a little plastic muffler. It's really not going to do much to restrict the air flow.

So again, on a working RX-7, the ACV and air pump have nothing to do with exhaust backpressure. If you read the emissions section of the FSM & take a look at the inside of an ACV & the LIM passageways, you'll realize this. A lot of people have taken the silencer tube off, including myself, and had no sudden loss of power.