Dont wrap your exhaust!

[Shadowrider]

John look up what the max EGT on the 912is and 915 of and it may surprise you. Then ask operators what the normal temps they are seeing? Basically glowing bright red. (915is is 950C (1742F) Exhaust in the picture has never seen over 1450f. Edge improved the exhaust from the stock rotax. Rotax last 20 hours before developed exhaust leaks.

[13brv3]

I recall reading that 304SS only has 20% of it's strength at 1400F. Seeing bent pipes makes me wonder if there was some sort of bending stress on the pipes that was more than they could withstand when they were hot.

As for wrap, I used it on a 912UL, but it never lasted more than about 15 hrs before starting to crumble.

Rusty

[Kitfox Pilot]

1610 is about the top egt, 1575 is normal for cruise in a 915is. Having egt gauges on most of our farm equipment, these 1600 degree numbers scare one when you first see them. 220 hours and no melt downs yet and everyone assures me this is normal for the i s engines.

[jrevens]

I recall reading that 304SS only has 20% of it's strength at 1400F. Seeing bent pipes makes me wonder if there was some sort of bending stress on the pipes that was more than they could withstand when they were hot.

As for wrap, I used it on a 912UL, but it never lasted more than about 15 hrs before starting to crumble.

Rusty

That's probably right. 321 or 321H are better choices for exhaust systems. It is basically type 304 with the addition of titanium. 321H also has a higher Carbon content. Additional stresses are exactly what I was talking about, with the welded fitting right at the apex of the bend, slip joints, etc.

Justin... no it doesn't surprise me. With those kind of temperatures, maybe you should be using Inconel. It's only money.