wrapping headers?

[lammbn]

Ok, so I've been thinking way ahead of the game as usual and have been thinking about my engine bay before i even have the car sandblasted.

 

anyways, I'm planning on using a 6 into 1 or 2 header and I'm worried about reducing engine bay heat as much as i can and i think the cleanest way to get it to a minimum is with with header wrap like my motorcycle has. I've always heard that you don't want to wrap mild steel or alumanized steel headers due to the increased temps the metal will see because the heat cannot escape. the increased temp overtime and many heat cycles breaks the metal down and it will deteriorate very quickly. stainless steel seems to be the only reccomended material to wrap for any extended use (most this info i could only find related to motorcycles and the added fact that header wrap always has a warning to never use for other than racing use.) another benefit i've thought of is that it also helps with heating an O2 sensor placed farther down stream in the runner collector

 

but after a few hours of searching i can't find stainless headers for sale anywhere and it seems they were only commonly made years ago in japan for quite a hefty price. i would be willing to pay more than standard headers of course, but not too much more than 500.

 

Now this car is going to be a weekend/sunny day driver only, never in the winter or when there is excessive salt or sand on the roads. Is the time it takes a wrapped mild steel header to break down a reasonable amount of time that it would only need replaced every 100,000 miles or so? i think that would be acceptable to me for my particualar use of the car.

[boardkid280z]

Another reason the wraps are said to cause corrosion on mild steel and aluminized steel is because they retain moisture and the moisture corrodes the metal. I'm not sure just the higher temps could really be the cause of a significant decrease in longevity, that seems possible, but unlikely. From what I've heard it's more because of the moisture that gets absorbed by the wrap material.

 

You should really look into getting the header coated with a thermal barrier coating. They can be quite thick sometimes and really do wonders for heat management. Many coating companies have different high temp thermal coats, just get the best ($$$) one you can find.

 

On the other hand, I think a wrapped header would probably last 100k miles. The wrap may not last that long though.

[lammbn]

I thought about a coated header. problem is that i don't think it would drop the engine bay heat enough to justify the extra cost, even though it would fit in better with my ultra clean engine bay look. wrap cost way less, even if i have to redo the wrap at 50,000 miles. on my motorcycle it was the difference between roasting my leg 10" away from the pipe to being able to touch the header within 5 minutes of shutting it off. it has lasted very well for how exposed it is and keep in mind this will be a very pampered car.

 

I'm more concerned about every degree of the air in the engine bay, i'm going to be running a port and polished MN47 head with high compression so the reason for the heat concerns is to do everything possible to fight knock. no matter how small, if it's within budget, i'll do it. and this is a big one.

 

as for the moisture issue, my material sience professor said that the metal will slowly oxidize itself due to the metal getting so much hotter and gasses being infused into the metal easier, over time it will weaken the metal. moisture shouldn't be any worse of a problem than it is on exposed, uncoated headers. i do plan on running a light coat of high temp paint under the wrap to help combat any rust issues that may occur though.

[ezzzzzzz]

Don't wrap. It's not for a daily driver application. I've have personally seen a header glowing RED HOT through wrapping after a 10 mile trek. You can control heat with shields and barrier material much better.