So I'm interested to hear about thoughts on exhaust wraps? I know that some people like them and others don't. Also some header manufactures don't like them. But the fact is that we have one heck of a lot of radiant heat under the cowl. Heat shields help some but I really just want to try to keep most of the heat going down the exhaust pipe. I know ceramic coating on the inside of the pipe is the best solution, but once a pipe is no longer new it becomes more difficult to apply and hope for it to stay. On my first ever engine build I had my rotors ceramic coated as that was supposed to reduce oil heating, but after I had a little detonation incident I found during the rebuild that much of the ceramic had come off due to the shock of detonation. In my mind, I don't feel that ceramic coating the outside of the pipe is any better than wrapping them as the heat is still absorbed by the metal but unable to radiate out.

   But the biggest argument against ceramic coating is that once it's done, you can't modify your pipe (welding etc.) without having it redone again. A good example of this just happened as I'd already had my exhaust completed some months ago, not expecting that it would change again... But then somebody on this list started saying how great his PLX wideband sensor was, blah, blah, blah, and suddenly I'm out a couple of hundred bucks and having to redo my exhaust because it's recommended that the sensor be located at an 15 degree angle, no less than 36" downstream from a turbo, while my old narrow band sensor was only 14" downstream. So rather than leaving the old sensor in place I decided to cut it off along with another (long ago) incorrectly placed EGT port and weld a patch over it, then install a new O2 bung downstream. Pretty simple to unwrap, weld and re-wrap.

So as far as wraps go... lets hear it. Good, bad or ugly.

  

 Next is blankets. I have the original mazda metal turbo shroud in place but then I bought a large turbo blanket to fit over that. The exhaust manifold that the turbo bolts to also has a stck Mazda metal sheild but I made one to fit over that as I feel these 2 items probably account for the largest source of under-cowl heat and since the oli cooler is directly below that, I want to eliminate that source of radiant heat transfer. I made this cover using 2 different styles of welding blanket sewed together like a quilt. The ball joint in my exhaust pipe, I decided to also cover with a blanket like this rather than wrapping it, so I made it into a sleeve that slides over the joint. Finally we get down to the muffler which is located inside a housing (more on that in a another post), due to it's location inside a housing I decided to put a quilted blanket sleeve over that one too.

Pics of all this and more at this link.