EXHAUST INSULATING WRAP

Just found this thread.  I would suggest against using exhaust wrap on a turbo engine for sure. I am currently replacing exhaust because my exhaust is collapsed.

The exhaust pipes can be damaged just like the pictures Rotec posted. This comes from over wrapping and causing too much heat retention. Anything can be ruined by doing  it the wrong way. Even a misused screwdriver can damage things. The header wrap should only be over wrapped 3/8" on the outside edges. Some wraps come with a thread in the wrap cloth edge as a guide. Some don't. I've  been wrapping Rotax exhaust for 23 years without a single issue. I have seen and heard of some with damaged exhaust because of over wrapping. Appled correctly there should be no issues.  The wrap greatly reduced under cowl radiated and convection heat. This helps save wiring, hoses, reduce heat on the Voltage  Reg and ignition modules. Some aircraft Mfg's wrap them from the factory. I used heat stickers on several parts to research this.

Interesting.  We have two exhaust systems that have collapse because of header wrap. Personally I don't think it has to do with how much overlap is being done. Back to back flying with and without didn't change under hood temps enough to make it worth it IMO.  On a 912ul and uls probably fine, but 915 after couple hundred hours I think you will run into issues. 

Dustin I agree with you.

While Roger has had great success I don't think he or others are doing the type 914 or 915.  This is simply going to fail in the end.  I am aware that some users, like the Stemme motorglider, use it however their application is a lot different than just flying as an aircraft.  In addition they remount the turbo to behind the engine and it ejects a lot of heat in that position.  

If you have a simple carb engine, they always tend to be on the rich side, perhaps you can get away with it.  If you have an injected engine, or worse yet a very hot turbo engine, I would not use a wrap.  A simple check online will show header manufacturers in the auto world will not warrant any header failures if they are wrapped.  There are lots of pictures to show what happens and long descriptions.  

To support what I am meaning about heat on a turbo, I got you a picture to look at.  Lean run turbo engines the exhaust gets to about 1800F, 980C, approximately.  A wrap will lead to failure at the bends or any slight restriction of "bump" internall on the exhaust.  Rotax says do not use it because people were asking for warranty on collapsed pipes with the factory exhaust systems.  

What is the take-away on this?  Well if you have a standard 912 with carbs and excessive heat under the cowl a wrap installed correctly might be just fine.  I personally would avoid it on any lean burn engines like injected models and turbo engines. 

Cheers

I agree the turbos run hotter and I don't  have much experience with the new turbos. The 912 iS has been doing well, so far.i haven't  heard or personally seen any issues, but caution sand tesearch are always best with education and knowledge. The last thing anyone wants I is an engine failure or having to replace expensive parts. When I do anything different than factory I talk to experts and move forward slowly. Us9ng science and physics also help.