Dont wrap your exhaust!

[Shadowrider]

I can tell you, even if you do it correct you may still have problems? I think there is apple to oranges being compared on the forums so take that at a grain of salt. 912ul and 912is exhaust temps are very different. On a 912ul or 912uls you may be okay? For sure I would not do it on any turbo engine, 914,915,916, and I dont think I would do it on the 912IS. What kind of egts are you seeing? IS engines run so lean the exhaust is extremely hot. I even richend my map up so I was not seeing over 1450F egts, but my exhaust still collapsed. I have about 200hours on my exhaust so it doesn’t show up right away. Slowly starts to collapse. Exhaust wrap keeps the heat in, which is good for a turbo, makes more power, but the exhaust can't hold up to it. 2 of the 4 headers collapsed. What I think is happening is you actually shock cool the exhaust. Cylinders 1 and 2 exhaust collapsed. I think as you are flying the wrap keeps the heat in and they get too hot. Then you pull power and the front of the exhaust cools quicker, because of direct airflow, than the rest of the exhaust that has been insulated and now the temp differences causes the exhaust to collapse and warp. Interesting it happened wright where the egts are attached? Its also causes the exhaust to warp and become misaligned. The gains you will see is not worth it IMO.

[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.