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Fresh Air Exhaust (F.A.E.) 

Fresh Air Exhaust

Fresh Air Exhaust (FAE) was invented in 2004 by Larry Mann, DC. Larry originally began Fresh Air Exhaust to help save the sport of Wake Surfing. At the time, the sport was under serious threat due to concerns of the Carbon Monoxide danger. “I went out to prove that boats and Wake Surfing were safe. The first time I tested the Carbon Monoxide (CO) level at the back of the boat I measured CO that was at lethal levels; I developed a new respect for Carbon Monoxide dangers present in boats”.

The first Fresh Air Exhaust (FAE) was made at home in the garage, shaping the downpipe with a hammer on the driveway (and looked like it); but it worked exceedingly well. Larry spent months refining the FAE and conducting Carbon Monoxide tests. He published his findings on the internet where they caught the attention of the U.S. Coast Guard.

The Coast Guard had the Centers For Disease Control (CDC) investigate. The CDC spent 2 days evaluating FAE. On the first day they strapped about 20 CO meters all around and behind the boat. We operated the boat for several hours without FAE. On the second day, with FAE installed and after verifying that all the CO equipment was operating properly, they asked us to put the boat into forward gear. At that point, one of the techs said “something just happened to all of our equipment”; the drop in CO levels was that dramatic. Their independent study reported a reduction of Carbon Monoxide levels of at least 90% with FAE.

What is Fresh Air Exhaust?

Fresh Air Exhaust (F.A.E) works by injecting the boat’s exhaust gases into the prop wash, and moves the gases away from the boat. This is done by connecting the FAE to the existing exhaust outlets. Consequently, the prop wash pushes the exhaust away from the back of the boat, where it surfaces anywhere from 100-300 feet behind the boat.Fresh Air Exhaust reduces Carbon Monoxide levels up to 98%FAE reduces exhaust noise levels up to 75%FAE Sucks …..the exhaust out of the boats engine.

3 Things To Expect From F.A.E

1: Reduced Carbon Monoxide Exposure

According to the Centers for Disease Control, Fresh Air Exhaust reduces Carbon Monoxide and other harmful exhaust gasses by at least 90%.

According to the Centers for Disease Control, Fresh Air Exhaust reduces Carbon Monoxide and other harmful exhaust gasses by at least 90%.Unless you boat is equipped with a catalytic converter, it produces lethal levels of Carbon Monoxide (greater than 10,000 ppm); levels strong enough to cause you to lose consciousness within about 3 minutes. Sadly, deaths from drowning occur. 

Even on boats with catalytic converters, the Centers for Disease Control recommends underwater exhaust (FAE) to further reduce Carbon Monoxide levels. Without underwater exhaust you are still breathing the toxic fumes from a V8 gasoline engine.

What is Carbon Monoxide?

Frequently, after a day on the lake, we feel irritable, nauseous, or have a headache. We typically blame the sun, the wind, the beer, a hard fall, or simply exhaustion. We may be experiencing the subtle toxic effects of Carbon Monoxide.  Engine exhaust and Carbon Monoxide are pulled into the back of the boat due to the Station Wagon Effect. Click here to see the “Station Wagon Effect” Video.

Carbon monoxide (CO) is an odorless, colorless gas formed by the incomplete combustion of fuels. When people are exposed to CO gas, the CO molecules will displace the oxygen in their bodies and lead to poisoning.

Children, the elderly, and anyone with asthma or other lung condition are especially vulnerable.Pregnant women need to be extra cautious because the developing fetus is particularly susceptible to Carbon Monoxide poisoning.If you are in a boat without FAE, sit at the front.

The Station Wagon Effect is aggravated by:

  • Traveling slowly (like wakesurfing)
  • A tailwind (a breeze from behind the boat)
  • More weight in the rear of the boat (like wakesurfing)
SWELL Wakesurf - Station wagon effects infographic
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The effects of Carbon Monoxide are cumulative; the longer your exposure, the greater the health risk. All pre-catalytic boats produce dangerous levels of Carbon Monoxide; even boats with Ultra Low Emission engines. Also, we now know that Carbon Monoxide poisoning causes oxidative stress to the brain and can cause long term permanent damage.

2: Reduced Noise - Improve Stereo Sound

Fresh Air Exhaust is the quietest boat exhaust available and greatly improves the quality of your boat’s stereo.Customers frequently comment that with FAE they only hear the sound of the water spray. We’ve had one customer return his FAE because he said it was too quiet and another that said he had to make sure not to start the engine when it was already running. Typically the louder your boat is now, the greater will be the noise reduction.Independent testing confirms reduction in noise levels of 50% or more. Tige Boats tested FAE to comply with the strict noise reduction standards in the European Union and recorded noise reductions of up to 9 decibels.

Customers frequently comment that with FAE they only hear the sound of the water spray. We’ve had one customer return his FAE because he said it was too quiet and another that said he had to make sure not to start the engine when it was already running. Typically the louder your boat is now, the greater will be the noise reduction.

Independent testing confirms reduction in noise levels of 50% or more. Tige Boats tested FAE to comply with the strict noise reduction standards in the European Union and recorded noise reductions of up to 9 decibels.

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3: Improved Engine Performance

Fresh Air Exhaust creates a suction as it moves forward through the water. This suction helps to pull the exhaust out of the engine. This is very similar to the exhaust configuration on outboard motors where the exhaust is pushed out through the propeller.

Most of our customers report no significant change in handling or wake, at all speeds; including surfing, wakeboarding or slalom skiing. We even have a few barefooter customers.

Since there are so many variables with boats (hull design, prop size and pitch, ballast) we can’t predict how FAE will work on your boat (though experience tells us it will work well). Therefore, we offer a very liberal return policy and yet have a less than 1% return rate.

How Does Fresh Air Exhaust Work?

Fresh Air Exhaust injects the boat’s exhaust into the propwash to move it away from the boat. Once the boat is at about 8 mph the exhaust is pushed about 120′ behind the boat; and greatly diluted. This is similar to Outboard Engines that have the exhaust exit through the boat’s propeller. Since the “Downpipe” of the Fresh Air Exhaust is in the frothy prop-wash there is less drag than would occur if the Downpipe were in undisturbed water.

The picture shows that the flow of the water past the outlet of the Fresh Air Exhaust Downpipe creates a low pressure zone (blue zones); this lower pressure helps to pull the exhaust from the engine. I refer to this as a venturi effect but when I was working with the engineer to develop this Computational Flow Analysis he explained to me how it wasn’t technically a venturi. I have to admit, I really didn’t understand the explanation so I continue to call it a venturi effect. Suffice it to say that Fresh Air Exhaust literally Sucks the exhaust out of the engine; see the video.

fresh air exhaust fluid dynamics
fresh air exhaust back pressure

Since the FAE Downpipe Sucks the exhaust out of the engine there is minimal back-pressure change until the boat is approaching Wide Open Throttle (WOT). Our back-pressure testing has shown FAE to not increase the back-pressure above 2 psi on some boats and up to 4 psi on some others, and this is at WOT. To put this in perspective, production boats with factory installed exhaust systems typically range between 2 to 5 psi back-pressure. For boating speeds up to about 3600 rpm the back-pressure with FAE is typically similar to the boat without FAE. By comparison, a stock Corvette (the high performance car) exhaust systems have about 3 psi back-pressure at WOT. Another perspective: 2 psi is a gentle puff to blow out a candle.

On a race car, the engine exhaust manifold, collectors and exhaust pipes are tuned (diameter, lengths, bends, etc) so that the Exhaust Pulse Wave is timed with the opening and closing of the exhaust valves. The Pulse Wave actually assists with sucking the exhaust out of the engine. On an inboard boat exhaust, water is injected into the exhaust gas just aft of the header; consequently there is no Exhaust Pulse Wave. Fresh Air Exhaust facilitates sucking the exhaust out of the engine similar to what the Pulse Wave does on a tuned exhaust system.

In general, inboard boat exhaust systems are not tuned. One of the best inboard boat exhaust systems is the Nautique Surf Pipe (just straight exhaust tube and the exhaust underwater; no muffler or flappers). This is the setup we’ve recommended to the boat manufacturers.Our engine performance testing, and our thousands of customers tell us that there is little if any performance change with Fresh Air Exhaust installed!

Our engine performance testing, and our thousands of customers tell us that there is little if any performance change with Fresh Air Exhaust installed!

fresh air exhaust boat speed
fresh air exhaust suction velocity
fresh air exhaust heat

Do I Need Fresh Air Exhuast On My Boat?

Simple answer, no. Should you get it, yes. Want to know more, watch the video below and read our Fresh Air Exhaust Article.

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Watch these videos to learn how to install an  F.A.E System on a Mastercraft Maristar and Malibu 247

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