Exhaust header wrap

[Roger Lee]

Header wrap; To use or Not to use. That is the question.

 

Well this may be a personal decision. What does it do for me? It helps keep the radiated heat off my hoses and wiring. It helps reduce some of the under cowl heat and stops any blow-by at the exhaust knuckle at the top of the muffler. Here's a test. Fly your plane and then land, remove the cowl and put your hand on your exhaust pipe. Then have someone drive you to the emergency room scream about the burns. Don't really do this because I said to test this, but I have header wrap and when I land and pull the cowling I can put my hand on my exhaust pipe and I don't need a ride and there is no yelling and screaming.:unsure:

Some might want to say, but what about carbonization? Well that would be more true if we had standard carbon steel exhaust pipes, but we have stainless steel which has much more nickle and chrome so this isn't a big deal. The header wrap Mfg. claims a 70% reduction in heat transfer. I don't really know if it is that much, but it does a great job.

Then someone will say how will I know if my exhaust pipe breaks. I have seen at least a dozen Rotax 912ULS pipes break. There will be absolutely no question in your mind this has happened. It will sound like yo just put headers on your engine. Another thing is stainless pipe rarely get holes in them. If they break it is a clean across break. The header wrap will just shred if this happens. Even during an inspection a first grader could tell if the pipe was broken. No more smooth header wrap. Just shreds.

So what are the draw backs? None that I can see. I have had mine on for almost 3 years and many others I know have had it 1-2 years without any issues. What are the benefits: reduction in radiated heat, hose protection, wiring protection, reduced under cowl heat and covers the knuck to reduce any exhaust blow-by at the knuckle. Many other aircraft use this same header wrap.

The cost is $45-$50 for 50 ft. of wrap 2" wide Thermo-Tec purchased at any automotive store. Cut a strip about 68" long times 4. Just wrap the first 15" down to the top of the muffler. Do not wrap the muffler. This starts at the exhuast port and goes down and covers the knuckle. Do not cover or allow the wrap to touch an EGT probe. It seems to cause fluctuating temps of 100F. No one seems to know why. Start at the top, dampen the cloth, do not wet it , only dampen. Use a hose clamp on the first wrap then over wrap by 1/4"-3/8" all the way down. Go under the springs and use another hose clamp. When the engine first starts it will smell like something is burning, but that goes away.

 

 

Now it's your turn to decide?

[airhound]

Header wrap; To use or Not to use. That is the question.

 

Well this may be a personal decision. What does it do for me? It helps keep the radiated heat off my hoses and wiring. It helps reduce some of the under cowl heat and stops any blow-by at the exhaust knuckle at the top of the muffler. Here's a test. Fly your plane and then land, remove the cowl and put your hand on your exhaust pipe. Then have someone drive you to the emergency room scream about the burns. Don't really do this because I said to test this, but I have header wrap and when I land and pull the cowling I can put my hand on my exhaust pipe and I don't need a ride and there is no yelling and screaming.:unsure:

Some might want to say, but what about carbonization? Well that would be more true if we had standard carbon steel exhaust pipes, but we have stainless steel which has much more nickle and chrome so this isn't a big deal. The header wrap Mfg. claims a 70% reduction in heat transfer. I don't really know if it is that much, but it does a great job.

Then someone will say how will I know if my exhaust pipe breaks. I have seen at least a dozen Rotax 912ULS pipes break. There will be absolutely no question in your mind this has happened. It will sound like yo just put headers on your engine. Another thing is stainless pipe rarely get holes in them. If they break it is a clean across break. The header wrap will just shred if this happens. Even during an inspection a first grader could tell if the pipe was broken. No more smooth header wrap. Just shreds.

So what are the draw backs? None that I can see. I have had mine on for almost 3 years and many others I know have had it 1-2 years without any issues. What are the benefits: reduction in radiated heat, hose protection, wiring protection, reduced under cowl heat and covers the knuck to reduce any exhaust blow-by at the knuckle. Many other aircraft use this same header wrap.

The cost is $45-$50 for 50 ft. of wrap 2" wide Thermo-Tec purchased at any automotive store. Cut a strip about 68" long times 4. Just wrap the first 15" down to the top of the muffler. Do not wrap the muffler. This starts at the exhuast port and goes down and covers the knuckle. Do not cover or allow the wrap to touch an EGT probe. It seems to cause fluctuating temps of 100F. No one seems to know why. Start at the top, dampen the cloth, do not wet it , only dampen. Use a hose clamp on the first wrap then over wrap by 1/4"-3/8" all the way down. Go under the springs and use another hose clamp. When the engine first starts it will smell like something is burning, but that goes away.

 

 

Now it's your turn to decide?

[airhound]

Roger, do you ever have to replace it under normal operating conditions? At Annual??

[Roger Lee]

Hi Al,

 

No you don't and you should explain that to your mechanic. I'm sure there is someone floating around that will say I need to look underneath. That's like saying let's sand off the car's paint to see if there is metal and it's split underneath, too.

If there is any type of crack under the wrap you will have long since known about it.

[S3flyer]

Roger,

 

What is the potential harm in wrapping the muffler? I ask because I read on the RV-12 forum where they wrapped the muffler and reduced oil temp 8 degrees.  Thread: http://www.vansairforce.com/community/showthread.php?t=59578

 

Note how close the oil cooler is to the muffler: 

 

My S3 is configured differently but is almost as close.  Thought I'd give it try this later this spring.

[Roger Lee]

Hi Dave,

 

No harm at all. many just don't need it there, but it can be added without any issues. I'm sure specific applications change from plane to plane.

[S3flyer]

Roger,

 

Wrapping the muffler like the above will be pretty straight forward but I'd also like to try to do something with the end closest the oil cooler. Any ideas on how to wrap the end? I was thinking of cutting four 10" strips then putting 2 of them in a cross pattern and the other 2 in an X pattern and holding them in place with a stainless steel worm clamps. I'd also wrap the ends under the normal wrap on the other side of the clamp. Thoughts?

[207WF]

I had to replace my wrap after about 4 years.  It started producing fine particles as the wrap deteriorated, and it made a real mess.

WF

[S3flyer]

Success!

 

My Sting S3's muffler sits on top of the radiator and directly below the oil tank. The oil cooler has a dedicated air scoop on the side of the cowl and is mounted at an angle. One edge is probably less than 2" from the end of the muffler. Based on the RV-12 success, I theorized that the muffler was kind of cooking the oil in the oil tank and the muffler was also heating up the air immediately behind the cooler. I took 2 actions:

• Wrapped the muffler with DEI Titanium Exhaust Wrap (http://www.jegs.com/i/DEI/186/010131/10002/-1). I needed about 15' of the 25' roll. The Titanium doesn't need to be wetted and is rated at a much higher temperature than DEI's other wraps:

  

• Put a DEI Titanium Pipe Shield on the end of the muffler to shield the oil cooler (http://www.jegs.com/i/DEI/186/010450/10002/-1)

  

The result at the same OAT (within 2 degrees) and same RPM:

• Oil temp reduced by 16 degrees
• CHT reduced by 11 degrees

I spent a total of around $60 on parts and two hours installing. Hardest part to find were 4.75" stainless steel clamps. I also should've pulled out the oil tank before wrapping which would've made it much easier to get to the muffler and much quicker to put the shield on.

[mocfly]

S3,

Congratulations on the reduction. Those are pretty impressive numbers.It's always nice to see an owner get temps in line, especially with summer fast approaching. CharlieTango is going after a larger oil cooler install to reduce his numbers, we are waiting for that PIREP.

 

It's quite a coincidence that theVANS guys are experiencing the same issues of high oil temp in the 912, goes to show how susceptible these engines are to slight changes in construction and component placement.

 

We still see our oil temps bout 40deg higher that CHT.