I'm adding CMI Aft Fire mufflers to my boat, and ditching the Corsa Silent Choice. So here is my question. I'm not giving CMI $750 for an air pump, when I can build the same thing for a fraction of the cost. For those of you with dual line air actuated mufflers, how do they work? Is it a momentary switch that pressurizes the cylinder, with another switch that opens a valve to release the pressure? Or are they pressurized to open and too close? Also, any idea what the PSI is to make these work?

momentary switch that pressurizes the cylinder, with another switch that opens a valve

Just discussed the other day.

Anyone know how to hook up this Livorsi exhaust?

I built one with a Harbor freight air pump, check valve and a 12v NOS solenoid about 10yrs ago under $100. Use the pump for the trailer tires also. lol
I might actually have 2 CMI pumps laying around. Never changed out this system because it works so good.
https://www.harborfreight.com/air-to...sor-69284.html
https://www.ebay.com/itm/Normally-Cl...-/121090156302

Close up

Thanks Rookie! That is what I was looking for.

Here`s the actuators if you`re looking


https://gaffrigperformance.com/boat-...silencers.html

Sick Stinger has an air pump Exhaust Gil manifolds risers mufflers rings

Thanks Griff!

Another question for you guys running this type of muffler, how are you running the hoses through the hull? I've been trying to zoom in on some pictures, and it appears that some are just running the hose though small holes in the transom. I'm really not sure I want to do it that way. Is anyone using a thru-hull fitting of some sort?

The 2 lines coming out thru that square fitting.. no idea where you get it thou .