i did a search, but the answers i found didn't quite sound correct. why wrap a header? pros? cons?
-spenc

 

I wrapped mine for a couple of reasons. One, it supposedly holds the heat in the header keeping underhood temps down and improving the scavenging effect (especially in supercharged applications like mine). Two, my header wasn't pretty so the wrap improved my bling bling stunna style engine bay

Zach

 

On top of that I might add that its a known fact that hotter exhaust gasses do not loose their velocity and exit faster than colder gasses.

 

move this to tech..there is an already a header wrapping forum how to. that guy can tell u why

 

Headers do corrode faster with header wrap due to the higher temps and the fact that they do hold moisture in for a brief period until it's evaporated. We had a big problem with high underhood temps cooking electrical stuff in my brother's car, header wrap cured it.

 

I agree, however in the October issue of SCC, in the Mazdaspeed Protege article, they state that hotter exhaust gases hurt performance. Can someone elaborate.

This is my header...

 

it depends on what's effecting the EGTs, I think. This is conjecture since I haven't read the SCC article to know exactly what they're talking about, but I suspect that they were referring to EGT as a function of motor tuning via a/f ratio etc vs. header wrap where we are merely retaining latent heat from the exhaust gas charge being expelled from the motor. From our chemistry, we remember that PV=nRT where P=Pressure, V=volume. n will be held constant, and R is a given constant. (maybe Rydberg? memory's a little shabby) In other words, as the exhaust temperatures cool, one can retain the same pressure by decreasing the exhaust piping diameter, decreasing the volume of the system. As such, we can use the header wrap to increase the temperatures in the exhaust system to increase the pressure, and drive exhaust gasses out more quickly.

 

Instead of wrapping what about using high temperature paint? Does this have any postive effects? Or nothing cause the thickness of paint is so small.

 

Thick, true-ceramic-coating from a company like JetHot or Swain Technology will have the same benefits of header wrap.

But these coatings will PREVENT moisture problems from occuring like when using header wrap.

 

I used cermaic paint first before applying the wrap in the image above. I did so not do prevent heat escaping, more so to prevent moister from getting trapped. You can see the flanges are black with 1200* black ceramic header paint.

 

JetHot helps, but no coating can even come close to header wrap for it's insulative properties. I can drive my car for 2 hours, hop out with the engine still running, and put my hand right down between the primaries. The heat coming off the header is similar to a radiator hose. According to a remote temp sensor, my engine bay temps decreased by 21 degrees. Not bad...

 

. I disagree, the true ceramic coating thermal barrier offered by Swain is very comparable to header wrap. I know, I had my Apexi header coated by Swain on my GSR and it was MUCH cooler than without coating, checked after autox runs, in the pits at trackschools, etc.

Jet hot is entirely different, but similar in the context of an alternate insulator

 

wrong.

I have felt a header after a 20 min session at summit coated by swain or jetcoat and it was cooler to the touch than the cylinder head AND there is no moisture issues like you have when you wrap

my header is wrapped and it will be taken off soon as I just had someone loose a header to a 3" crack from wrap - IMHO not worth it

 

From the Thermo-Tec website:

"To finish off a clean and well-protected Exhaust Insulating Wrap application it is recommended to use the Hi-Heat Coating. The coating will protect the wrap from abrasion and harmful liquid spills. Extra resins and binders toughen the surface, extend the life of wrap by protecting it from friction, and seal the pores to minimize the penetration of harmful liquids."

I think with this, the header wrap will stay cooler while trapping heat from escaping through the tiny crevesses that header wrap has. It is a step often neglected. It will also seal it from moister.

 

the wrap seals moisture IN , hot and cool creates moisture and the wrap holds it against the header ...

 

Hmmm. Interesting.

 

i learn somthing everyday on h-t

 

I wonder why so many high end headers come stainless if a thermal coating like JetHot is the best way to go in terms of performance? Do Hytech or SMSP offer a JetHot type coating for their custom headers?

After seeing Austin's results with his Hytech header (see ITR forum) I'm seriously considering upgrading from my Spoon header with custom dents on the downpipe.

 

You can use thinner gauge material. A coated mild-steel header cannot be welded because of the coating.

 

All SMS headers are coated by Airborn. Hell you can even pick the color Dave uses mild steel, though I believe he's considering some stainless ones, just because of market demand.

Warren

 

>>my header is wrapped and it will be taken off soon as I just had someone loose a header to a 3" crack from wrap - IMHO not worth it <<

2 1/2 years, 25,000 miles. Same header, same $30 wrap (never removed).

I guess we all have our own experiences with what works and what doesn't...

 

HyTech uses 304 Stainless for its heat retention, used to coat all headers before he started to use 304...I coated mine because I wanted a slightly cooler engine bay for my daily driver.

SMS uses mild steel(heard that he will make stainless for more $$) and has all of the headers coated by Airborn in NC.

After wrapping my old JDM 4-1 I was willing to pay someone to coat the header, what a royal pain in the butt...the coaters also had a lifetime warranty on the coating.

Austin

 

to chime in as another person who didn't read the article, your EGT probe ideally should be as close to the exhaust of your engine as possible, so _ideally_ the amount of heat lost through the exhaust piping wouldn't effect the temps reported. (all this is second from reading I've done, not actual experimentation)..

I don't know what the article was talking about, but generally EGT tuning is tuning your ignition timing and air fuel ratio as I recall.. high temps meant too lean..

blah..

 

Wraping a header will improve perfromance, But at a cost it cuts the life of the header in half due to extreme heat soak. <-----From the mouth of a TOP FUEL car builder

 

for you Toronto-based people, here's a local company that does ceramic coating. I've never used them, but apparently they're good.

http://www.fireballcoatings.com/index.htm http://www.fireballcoatings.com/index.htm