I don't know what is called but i've seen pictures of both down pipes and headers wrapped in some kind of fabric material, obviously not "fabric" because it's high-temp but just trying to describe it the best i can.

 

exhaust wrap, header wrap, etc.

pros: helps to keep exhaust heat where it belongs and (to a lesser degree) off of where it doesn't belong

cons: supposedly promotes cracking (i say supposedly because i've never used it, and while i don't doubt it, it's second-hand knowledge)

 

pros = no more fuel boiling in the damn carb.
Cons = ugly as hell and itchy too. God damn I will never wrap my header again. Imma try coating it next time.

 

cons - pipes rust and fatigue quickly, depending on the wrap used often collect moisture overnight, collect oil and steam and smoke while they warm up


pros,, cant think of any, some BS about exhaust velocity
,,but its already transonic in a rotary and keeping the heat in causes longevity issue for the pipes

keep it on the honda
or wrap the things that need protecting
( in oz/brit/jap cars the brake clutch and the wiring down on that turbo side )

 

Spend the money and get ceramic coating. It keeps the heat from radiating off the pipe and will protaect from corrosion. The wrap is messy, not as effective and will trap moisture contaminents etc.

 

on the rotary since the exhaust is right under the intake, putting insulation between the two does actually help. its not really about keeping the heat IN the exhaust (there is more than enough), its more like keeping it out of the intake.

but yeah you're suggesting the other way, not wrapping the header, but you wrap everything else!

i wrapped the INTAKE on the P port, and it really made a big difference, the amount of fuel the engine wants varies pretty drastically with temperature

 

from another thread https://www.rx7club.com/showpost.php...4&postcount=42


"thermal conductivity, k, is the property of a material that indicates its ability to conduct heat."

the bigger the number the more heat is transferred:

Aluminum alloy 180-120

Steel carbon 43

Stainless steel 12-45

Mica .71

Fiberglass .04 (but resin melts approx 1000F)

Air .024 (illustrating the importance of heat shields & air gaps)

Cast Iron 55 (or less, composition dependent)

refractory mineral fibers .04 (aka rock wool)

high performance refractory ceramic fiber--typically <<1.0

since AIR is almost the best thing on the list, and its price per foot is also a lot lower than anything else, this makes a good case for some simple heat shields with air gaps

 

there's also the gold foil stuff which is supposed to reflect unwanted heat away or something like that, and keeps parts cooler. Pretty much the same stuff the whole engine bay of the mclaren f1 is wrapped in that stuff.

 

Yeah, but the problem is, you're still adding heat to the engine bay, which means you're making it harder to reject the heat from the cooling system. I'll take a wrapped exhaust over nothing any day of the week (but ideally, ceramic coated).

 

wrap collects moisture which is bad for a daily driver that does a lot of short stops and go because you need to boil the moisture off of with high exhaust temps it will rot your pipes quicker.

 

Wrap normally won't collect moisture and cause rust in a normally driven rotor. By
that I mean one that gets up to operating temps for at least a few minutes before
shutdown. Once a rotary warms up the exhaust header is so hot that all physical
water is driven off as steam. In fact rotary headers get so hot that I would think
chemical water is driven off as well. I think thats the reason when you install
wraps they say to take it thru some heat cycles, so all the water gets out of the
wrap and transforms it into a solid heat shield.

I'm curious how your headers would even get significant amounts of moisture on
them unless your driving in a very heavy rain storm or doing a rally. Really, how
wet does your engine bay actually get anyway. Ok, the headers stick down a bit
and may get some spray on them. I'll give you that. Then don't wrap down to
that point just wrap down to the oil pan.

I just get tired of folks condemning header wrap because it causes rust or cracked
headers. I have yet to see actual proof of that. Where I have seen it, the headers
were already questionable and cheap.

Header wrap is about 10 times cheaper than ceramic coating and just as affective
for mitigating radiant heat in the engine bay. I say go for it. I wrapped my last
header and sold it that way to a buddy and he kept it wrapped as well and its
holding up fine. Oh and if you buy a package of wrap meant for a v8 you can
split the cost with a buddy and wrap both your headers for more savings.

 

Just a con that may not be applicable in all cases. When I first built my RX7, I bought a Pacesetter header and wrapped it to reduce underhood temps. Worked great for 5 race weekends then in the 6th it blew a hole out of the back header right at the outside of the first bend during my saturday race. The hole was about a quarter sized hole and when I was looking to have it welded overnight so that I could race again on Sunday, the welder couldn't help me. The steel had degraded to the point that it was like sandstone for about 2 inches on either side of the hole and the for about halfway around the header.

Ended up slicing a regular piece of exhaust pipe bend in half and hose clamping it on. Got me through the race on Sunday then I had to order a Racing Beat header and redoing my exhaust before the next race. Because of this experience I didn't wrap my new header and it has lasted 14 years.

Eric

 

The Pacesetter would have done that wrapped or not wrapped

They're too thin and can't handle the heat, especially in a race situation.

This is what I mean, wrapping probably had little to do with this failure yet it
gets the blame. Then you go out and get a RB header and keep it unwrapped
and claim it did better. Apples to oranges, no real comparison here and no
evidence one way or the other about wrapping. It just shows that the Pacesetter
is a cheap header, which we all knew anyway.

 

+1

 

this is true for me as well.

however the first track day with the Pport, the UNWRAPPED header lost all of its scale for the first foot, AND changed color. the exhaust behind it also seems to be sagging a little. i think wrapping it would be bad. on the P port though its easier to wrap the intake...

on a side port street car though, i see no problem with the wrap

my case also illustrates the importance of having lots of exhaust hangers, its not just the heat, its the supersonic pressure wave every time the port opens that's hard on everything

 

Valid points and I did take them into consideration. The issue I have is that the Racing Beat headers are made of mild steel as well (though a better grade) and I was always concerned about them doing the same thing, but taking 8 races instead of 5 races to turn into sandstone.

Maybe I should wrap the headers before the 3 Hour race in a couple of weeks and see what happens. I can always expect you guys to cover the cost of new headers, right????? LOL, just kidding.

Eric

 

hate heat wrap

too ugly, I don't care about the supposed benefits

 

I think it looks fine if you install it correctly. I don't like flashy stuff anyway.

 

on my 91 i had a wrapped rb mild steel header lasted for over a year till i sold the header

it most definitely dropped under hood temps and my intake manifold was noticeably cooler

i plan on wrapping the next header i get and the whole exhaust under the car to keep the floor cooler

 

I have a header in the car, there is an oil change pit in my garage and I have wrap laying around somewhere. I just need to get off my *** and do it.