Aero Muffler

Jim Blackwood · September 30, 2019, 08:07:10 AM

Airplane engine exhausts are not usually subjected to salt spray unless they are operated at low altitude over the ocean. The salt can make a huge difference, retaining water and causing rapid corrosion. I've seen wrapped headers rust through completely in one year's time to the point where they were unrepairable. Salt water boat exhausts might be a better comparison.

Stainless comes in many grades. Most have both Chrome and Nickel alloyed in along with other elements. Either may predominate. Typically Nickel stainless will be non-magnetic and chromium stainless will be magnetic but it depends mainly on the Nickel content. Lower grades can and do rust. To know the properties of a particular grade of stainless you have to look it up. Then you can do a proper comparison.

Jim

Lin · September 30, 2019, 10:01:42 AM

The 304 grade stainless used by Aero is not magnetic, and the 409 used for the Magnaflow 12774 is magnetic due to its lower chromium content. Research online says that 409 is the most common grade used in exhausts. It can develop surface rust but that is generally inconsequential. Interestingly enough, the 409 steel is supposed to be pre-heated before welding.

Scott & Heather · September 30, 2019, 06:54:37 PM

Only downside:

It's loud.

But not nearly as obnoxious as a straight pipe.

The end.

Oonrahnjay · October 01, 2019, 08:15:09 AM

Quote from: Scott & Heather on September 30, 2019, 06:54:37 PMOnly downside: It's loud. ...

Which brings up a basic question in my mind -- what's (usually) the easiest engine to quiet, a 2-stroke or 4-stroke? Which is louder with a straight pipe?
Thanks, Bruce

luvrbus · October 01, 2019, 08:40:33 AM

Turbo engines are the easiest 2 strokes or 4 strokes Lin's 8v71 NA will be a loud sucker with AERO or a Magaflow and he will not like it.Bruce both are about the same noise level with straight pipes

DoubleEagle · October 01, 2019, 12:28:37 PM

I looked at a Eagle for a friend that had straight pipes on a 8V71 NA, and I found it to be irritating, not enjoyably loud. In a campground setting you would not make any friends. The Aero Muffler would be better, but without the turbo, it would not increase your popularity.

Utahclaimjumper · October 01, 2019, 01:52:29 PM

A turbo will lower the sound level quite abit,, the resonator will take out the sharp crack.. Overall a mellow sound and not irritating.. I have had folks mention when I passed them they knew I was there but not obnoxious.>>>Dan ( My exhaust exits the right rear corner)

Lin · October 01, 2019, 04:02:27 PM

Well Clifford, You may be right. I did not consider that the Turbo was quieter. I guess I'll find out soon enough.

Lin · October 08, 2019, 06:14:32 PM

We have installed the Areo muffler, and I want to post the results in case anyone else is researching such a switch. I have not yet gone on a trip that would help determine whether there is any fuel, heat, or mileage benefits, but I can report on the sound difference. I downloaded a sound measurement application for my phone and recorded before and after readings. I measured from each corner outside the bus and also back, middle, and front inside. For the most part, there was a 3 decibel difference at each location except the front to outside corners. For some reason, they were about 10 Db higher after the install. This seems kind of strange since the driver's seat had only a 3 Db increase. The back corners measured from about 10 feet away went from 73.5 Db to 76.5 Db. The inside back (bedroom) was 68 Db and increased to 70.5 Db. The middle of the bus (kitchen) went from 60 to 64. The driver's seat went from 60 to 63.

These numbers were all at idle. Although it might not seem like much, it was definitely a lot louder. The really noticeable difference though was when accelerating. I did seem that there was quite a roar at times. Once up to a cruising speed though, it did not seem to be very loud at all from where I was sitting though. I think that leaving a campground at 4 AM would get a bit of attention. Definitely better to air up with my auxiliary compressor. I probably would like it to be quieter for my neighbors, and if there are no mechanical benefits, this would not be a good project. If it helps keep heat down and contributes a little extra power and fuel mileage, I would consider it a good trade-off though.

The old muffler was a 36 inch long cylinder with an approximately 15 inch diameter. My guess is that it weighed at least 80 pounds. The new one is only about 7 inches diameter, 30 inches long, and weighs around 15 pounds.

luvrbus · October 08, 2019, 07:12:11 PM

Wait till you engage the Jakes it will rattle your teeth

Lin · October 08, 2019, 09:48:06 PM

I did use the Jakes. Sounds like trucks I have heard, but it is okay from the driver's seat. I may change my MCI badge to Tesla so people will think that sound comes from somewhere else.

Jim Blackwood · October 09, 2019, 09:03:42 AM

A 3db level increase equals double the sound level.

Jim

Lin · October 09, 2019, 09:14:23 AM

Could be. I do not completely understand the science. It seems to say online that a 3db increase is twice the energy, but that that does not translate to the perceived sound level as being twice as loud. Anyway, it is certainly very noticeably louder.