thermal exhaust wrap
 

I am going to be installing my exhaust system soon.
I have the street port headers and centersection.

Would thermal wraping the headers help make power.

Plus i think it would help make the exhaust spit fire and keep underhood temps down.

or would I just melt the exhaust.

more power - maybe
lower underhood temps - possibly
spit fire - doubtful
header rot - likely

If they aren't chrome paint them white with high heat paint especially for headers. White keeps heat in and black lets heat out.

it will crack your header. The header is too hot and somehow has to get rid of the heat. Your best bet to keep the heat under the hood low is to install a shield under the intake manifold to keep the exhaust heat away.

The color will only reflect or absorb light energy, not heat. And make sure you get at least 1500 degree paint, the 500 degree stuff will burn right off.

I do know alot about exhaust and I am not even going to start on whats wrong with that.

Please tell us what is wrong with that. It sounds interesting. I am going to be taking some thermodynamics classes soon and I want to learn all I can before I take it so I don't fail miserably. thanks

yea i was considering wraping my whole new system,
mainly the center section,
why you ask???

well to make a long story short everyone knows or should know that you can only use stuff like stainless steel or thick wall mild steel on the rotary exhaust system,
i have a rb header and an aftermarket muffler but no pipe to connect.
so of course im going with stainless steel,
although more expensive its alot easier for the exhaust guys to custom bend to my car,like over the rear axle.
so by being easier to bend it will overall come out cheaper because the can bend it right there without haveing to ship the whole pipe out to have it custom ben by a big press.
so with that said and done i decided to go with stainless steel 2.75",
because stainless steel is alot thinner then thick wall mild steel the exhaust noise will be louder.
"interior resonance"
so i think by wrapping the pipe it will act as a damper to help reduce interior resonance caused by sound vibration.
as for the header it was just to keep heat down.
plus i plan to have alot left over.

I too was thinking about wrapping my headers to keep the under hood heat down. I was only going to wrap the sections of the header that were under the hood though. I have a Yaw carb sitting right above that header, it looks like trouble to me.
Someone else posted that the way to go was to ceramic coat the header.
Any thoughts?
hanman

How the hell would different color paint change the amount of escaping heat?

Or you could just buy/make a heat shield for you header like RB sells to keep the heat from the header away form the intake if thats what some of you were worried about...Personally I dont care, I just wanna be able to have my system at all :).

Racing Beat Heat Shield

~T.J.

PS - When I get my new header, the only reason I was gonna shoot it black was for looks cause its slightly worn by now...

I know the paint color won't change the rate of heat tranfer. But what the paint is made of will. Also different wrap materials, amounts, brands ect. ect. This guy was sayig that he knows a lot about this stuff and I wanted to learn what he knows. BTW I have a great Idea for a good tepmorary cold intake charge. I'm gonna make a separate thread for it though.

Thermal transfer rates are affected by the color you choose but not for the reason you think. Hard to explain, but the properties that affect this also affect the color. We see black as a result of the materials used that give the mfg the ability to radiate heat more efficiently. Does that make any sense? The "blackness" of the paint is there on the side "facing" the header as well as on the outside where your eyes see it. the materials that are more effective at reflecting radiant energies like light and heat happen to appear to our eyes as white or whitish. Your best bet is to ship the header off to JetHot and get the JetHot 2000 coating. It cost me $100 to coat my set 7 or so years ago, but then, it was one of four prototype headers in America at the time. Don't know what they want for it now. The headers are still fresh. I'll post a pic. This is even after three engines. Believe it...:cool:

I just got back from work and went to take the picture. There was mud down there and I foolishly poured some water on it that I was going to wipe down with a rag. The resulting steam has left that tan color on the header. I'll have to wait 'til it's cool before I scrub that crap off. There is a little bit of rust starting to show around the welds but no large scale damage is showing on these headers. It's great stuff...


https://www.rx7club.com/forum/attach...&postid=533818


The headers also run a lot cooler. Enough that you almost get within an inch with your bare hand before you feel radiant heat! This shot also shows the "heat collector" I built to pass inspection since they require a heat-riser tube. It doesn't actually do anything because of the substantial gap between the header and "collector" plus the noted lack of heat coming from the headers, but it fools 'em every time!:cool:

?????????
 

Umm, wtf kind of header is that?:confused: https://www.rx7club.com/forum/attach...&postid=533818

Custom built Rotary Performance, amigo. We called Racing Beat and told them of the streetport 12A with a basically stock Nikki that would be massaged in the future. We then asked for primary diameters and length as well as collector diameter and length and RP built them from their recommendations. I asked Ari and Chris to try to emulate the "bundle of snakes" header look seen on the Gurney-Weslake racers of F1, but what the hell can a fella do when there's only two freakin' pipes?! They gave it their best shot and then called JetHot and the "other guys" asking for a coating that could survive 1900 deg F sustained. The "other guys" had nothing to offer. JetHot said they had no product that matched the specs but said they were working on a new formulation that was currently in its testing stage on two of their employees racing RX-7s. They would give no guarantee on durability, but cut a great price with me understanding it might not last. It later became JetHot 2000...

Neat, do you have any other engine shots you could post? I think that would be cool to see just how everything is set up on your engine.:cool:

yes, anything that keeps heat in the headers will help performance. Keeping in the heat increases exhaust velocity which scavenges out more exhaust gas from the chamber allowing a more "cleaner" mixture for the next combustion cycle. the problem with the wrap versus coating is that the wrap is just on the outside. the heat is trapped in between the wrap so the metal gets heat fatigued quicker and the header cracks and fails sooner. since the coating is on the interior and exterior of the header, less heat is kept in the metal, prolonging the header's life to a normal header, while working better on heat control then the exhaust wrap. so i would get the coating. well worth it performance wise and will cost less in the long run.

In one paragraph, you cleanly explained a very difficult concept. You need to be writing manuals. It took Car Craft and Hot Rod, a 3 page article and pictures to convey what you have in your 120 words or so! Impressive! :cool:

I'll post some more pics on Wednesday of the engine bay...;)

tons of knowlege that needs to make me money somehow. lol, jeremy's guide to all the useful generic performance tips. thanks for the comment. i don't take up enough pages for a publication or a "proper" school paper.

Umm in that picture with the blue hose going to it, what is that? It looks identical to the stock BOV on my toyota supra turbo...

I wrapped my ceramic coated RB road race header. No noticeable (seat of the pants of mph at end of 1/4mi) performance improvement.

Underhood temps went down a bit. On a street car I would suggest some type of heat shield instead of wrap.

The downside of wrap is that the header will deteriorate due to trapped condensation. Don't really understand this concept, but was given this info by very knowledgeable people.

Nope!! I ran regular ol' thinwall mild steel for 23,000 miles last year with no problems!

Now, the MUFFLER has to be made of Kryptonite and Lead or something... but the pipes will be just peachy. What do you want to do is put a flex connection in there, or the headers will crack. Y'see, the exhaust expands and contracts as it heats and cools, plus the engine torques over, and eventually you will crack your headers, especially if they're not well supported in the rear (you did bolt them to the tranny-mounted hanger, right?). My headers and 1/2 of the exhaust system turned bright blue after a track day but I had no burnout problems.

The muffler, on the other hand... sheez! The pipes are fine because they cool off easily enough with the airflow, but the muffler keeps all of that heat inside. I went through lots of mufflers :D Eventually just threw a stainless-steel quiet-as-a-mouse muffler that I borrowed off of a Lincoln (it didn't need it anymore). Still ran high 15's through that little 1.75" muffler :)