That's pretty slick about Damian's setup! I'll have to remember that one.

I got an old, broken airbox and cut the silencer out of it. It is pretty big, unfortunately - dunno if it will do the job as far as space is concerned. I also have an airpump muffler from an FC I'm going to experiment with - it's pretty big as well.

Thanks for all the input everyone! Keep coming with suggestions!

Dale

 

I have tried many different solutions to quieting the moo, including something very similar to damian's setup above, and none worked to my satisfaction. However, what I am running now is pretty quiet. The key seems to be to put a 1/4" restrictor in the hose (think 1-hole stopper). I made a restrictor and put it in the hose, then screwed a small metal lawnmower muffler onto the end. The description sounds awful, but it really looks fine and is effective. Sound-wise, my intake is not at all obnoxious though you can still hear the bov: https://www.rx7club.com/3rd-generation-specific-1993-2002-16/intake-fabrication-how-pics-310727/

 

It does not make sense to me why you would only hear the airpump for the first 30 minutes. But I'll be honest, I don't know jack about the air pump other than it's designed for emissions, clutters the engine bay, & robs slight HP.

This is my set up.
Mild streetport
DP, MP, stock muffler
Apex'i BOV
no airpump
M2 Intake, the older stainless steel one not the CF. Which one do you have?

My car is fairly quiet, it does have a low rumble to it but that it's, at WOT it's certainly much quieter than the civics with fart cans that are runing around here.

With the stock intake and when I had the air pump: I could only hear the turbos and the BOV. Soon after the air pump was removed. No change in sound. My last mod was adding the intake box, and I did not notice any change in noise level at all. The car did respond better though. I suppose that if I reinstall the airpump I would get that mooing sound that everyone is talking about since it seems to happen even with Adam's Chap bastard box.

It makes sense that the M2 box does not muffle sound as well as the plastic stock box (i.e plastic V.S. stailess steel). As far as aftermarket intakes are concerned, the enclosed type boxes are the next best thing for low audibility.

Why don't you remove the air pump? I mean you are already running a midpipe and besides it cleans up the engine bay.

 

I don't hear a moo with my A'Pexi(?). It comes with a restrictor that in the diagram below(#40) goes in the long CRV(center) and not the air-pump elbow hose. The CRV doesn't vent enough to cause restrictor lag anyways. It doen't really make sense in the diagram and I've tried it in both hoses with no moo either way. I didn't bend a single pleat on the filters putting them in. Maybe you're doing it the hard way or the hard pipes fit better.

 

I have the M2 carbon fiber box and it works well. Yes, it's louder than stock but it doesn't annoy me. I hear the bypass valves but not the air pump.