Wrapping stainless header

[vividracing]

Originally Posted by Tbird232ci

If you're using fiberglass wrap, soak it in water before wrapping. It keeps the fibers from floating around, and makes it easier to work with. With it wet, you can wrap and pull it tighter without it unraveling.

I wish I knew that then lol. Oh well, I got it wrapped really good anyway and it looks really nice. I guess even if I knew to get it wet I wouldn't because I needed to spray it with the protectant I also got for the wrap and couldn't wait for it to dry first.

-RyanG

[tonystewart]

Originally Posted by wootwoot

Evidence? I have yet to see a coating that performs better than an actual barrier like wrapping. The coatings are just not thick enough to compete.

In any event, I'm asking about header wraps, not header coating.

Plenty of evidence across the motor sport industry.

"Imagine a world in which we are all enlightened by objective truths rather than offended by them"

[vividracing]

Originally Posted by tonystewart

Plenty of evidence across the motor sport industry.

"Imagine a world in which we are all enlightened by objective truths rather than offended by them"

He's asking about evidence for coatings that keep the engine bay cooler. Coating/ceramics don't, at least not as much as wrapping. Coatings just protect, not insulate. They absorb and radiate heat. Wrappings insulate and reflect.

[wootwoot]

Originally Posted by tonystewart

Plenty of evidence across the motor sport industry.

"Imagine a world in which we are all enlightened by objective truths rather than offended by them"

Coatings are good, but they can't do what wrap can do.

Anyone wrap a header for an extended amount of time on another platform? People on the net seem to think its harmful but I haven't seen a single stainless header that failed because of it....

[vividracing]

Originally Posted by wootwoot

Coatings are good, but they can't do what wrap can do.

Anyone wrap a header for an extended amount of time on another platform? People on the net seem to think its harmful but I haven't seen a single stainless header that failed because of it....

Motorcycles do it quite often to prevent the rider getting burned. I've also seen some dragsters do it too. I know many many turbo systems wrap the exhaust part of both the turbo housing and tubes as well to keep the intake side cooler.

[swarb]

Those of you that have wrapped, which width and length did you purchase? I'm thinking the 2" x 25' will work.

Anyone know difference between titanium, black and tan? Just the color?

[FRS Justin]

Originally Posted by swarb

Those of you that have wrapped, which width and length did you purchase? I'm thinking the 2" x 25' will work.

Anyone know difference between titanium, black and tan? Just the color?

Go to http://www.designengineering.com/ and use the calculator. You will be surprised how much it takes

[Target70]

I put DEI Titanium on my OFH, it took 2" X 50ft. The Titanium doesn't need to be wet, and is really slick and resistant to spray on coatings, oils, and contaminants. It does have some kind of fiberglass in it even if it is not the main insulator. It was my first wrap and I had trouble deciding where to start from and work too, and then getting my overlap (advised 1/4) correct, so I wrapped and unwrapped it like 4 times over a couple of hours, and ended up with the fiberglass prickle in my hands/forearms so you might want to wear gloves. Wrapping the slope of the collector was giving me a hard time, the wrap kept slipping, so I just stopped there. I might go back and try it later with my left over wrap ~8ft, It might be enough to cover my overpipe too. I don't remember how the stock manifold radiated heat, but I agree vividracing, I can get my hand pretty close before I feel the heat radiating off of it. Without all the packed insulation and shielding of the factory manifold to retain the heat, the pipe cools off very quickly after turning the car off.
A tip, if you have a fixture or a large vise you can use to mount the header so you don't have to hold it between your knees while you wrap will probably make the task much easier.

[Hagbard]

I did my headers in the DEI Titanium 2" wide used a 50ft roll, No pre-wetting or any coating needed with the Titanium wrap. The Stainless steel ties work really well too to hold it on.

[lamawithonel]

Originally Posted by wootwoot

I just bought a new Tomie header and was thinking of wrapping it with Titanium wrap. I have been researching on the web and people swear up and down that wrapping a mild-steel header degrades it but I can't find any info on wrapping stainless. I would prefer to wrap as oppose to coating it as the wrap is much more effective. I really have two worries:
1. Will the wrapped header send more heat into my secondary cat and burn it out?
2. Will the wrap fatigue the stainless and shorten its life span?

There are two problems header wrap presents, corrosion and heat stress.

The corrosion problem occurs because thermal wraps are porous. If a wrapped header gets wet and it is not hot enough to dry, the wrap will hold the moisture against the header. Stainless steel should be less susceptible to this problem, just keep in mind, stainless is not stain proof. The best thing to do is paint or ceramic coat the header prior to the wrap.

Heat stress occurs when the metal expands and contracts. Combined with residual stresses and vibration, this can lead to cracks. All headers will do this, regardless of insulation, but adding insulation exacerbates the problem. Additionally, a tightly wrapped header can introduce other stresses since the wrap won't expand at the same rate as the steel header. Generally, though, if the header is of good quality it should not be an issue. If it's something you're really worried about, you might consider heat treating or shot peening the piece to remove any residual stresses.

Originally Posted by vividracing

Wrapping doesn't help with corrosion protection, ceramic does.

Ceramic doesn't insulate, wrapping does.

That's the basic premise of either option. If you're worried about the header metal deteriorating or rusting, ceramic is best, but ceramic also is a good conductor of heat and will absorb and transmit the heat into the engine bay anyway. Ceramics also look good and you can get it colored to practically anything you want.

<snip>

Not all ceramics are created equal. The better coatings will provide some insulation, but you're right, it won't be as good as a quality wrap. See below and http://www.ft86club.com/forums/showp...4&postcount=31

Originally Posted by swarb

Those of you that have wrapped, which width and length did you purchase? I'm thinking the 2" x 25' will work.

Anyone know difference between titanium, black and tan? Just the color?

I'm not sure about length, but it's best to get two widths: wide for the long, straighter pipes and narrower for the intricate bends, around flanges, collectors, etc. Look around on YouTube. There are some good HOWTOs out there.

DEI's "Titanium" wrap is made from basalt fiber (volcanic rock), their black and tan wraps are made from fiberglass. Basalt fiber is a superior material with lower thermal conductivity, higher thermal stability and better tensile strength than fiberglass.

Aproximate thermal conductivities in W/(m·K) for some common heat shield materials (lower is better):

• Fiberglass: ~0.034 - 0.4
• Basalt fiber: ~0.031 - 0.038
• Zirconium dioxide: ~0.69 - 2.4
• Inconel 600: ~14.54 - 14.9
  

[Hyper4mance2k]

Originally Posted by swarb

Those of you that have wrapped, which width and length did you purchase? I'm thinking the 2" x 25' will work.

Anyone know difference between titanium, black and tan? Just the color?

Tan is just the glass wrap; black is the glass with black dye. I have always used the black and it is a mess when putting it on -if you do it correctly and wet it first. The titanium is newer; I haven't heard anything about it.

For everyone afraid of header wrap, I wrapped a used junkyard header on one of my Rx-7s. The header lasted 8 years in Seattle, daily driven, before it finally cracked at one of the welds... Note, it was a used header that I found in a junk yard.

Also, ceramic's insulate if they're done correctly. I had one of my Rx7's track headers ceramic coated internally & externally and I could actually touch it after a 60 second autoX lap. Mind you, my car was tuned for 1900* exhaust temperatures.

I wish this place was still local: http://www.performancecoatings.com/index2.html

[vividracing]

Originally Posted by swarb

Those of you that have wrapped, which width and length did you purchase? I'm thinking the 2" x 25' will work.

Anyone know difference between titanium, black and tan? Just the color?

I used the 1" by 50ft black. There's no difference between black and tan besides the look, and fiberglass wrap absorbs and stains with any liquid that touches it, if you get oil on tan wrap, it'll show there. So I got black to avoid that and make it look better.

I have the OFH and it was pretty straight forward to wrap but the collector was a pain especially with the sensor location. I specifically used 1" because 2" makes it more difficult to wrap around corners and turns, I had enough to reach the end but I trimmed the rest too early as I was trying to zip tie it and I had to keep moving the zip tie point further up, in my case I finally managed to lock it in just after the collector. Yes it doesn't cover the "entire" header but 95% is still good, the results are great, I feel very little heat coming from the engine, the wrap keeps the engine bay cool(er).

50' is plenty if you wrap it right and make the overlap on the straights as little as possible without slipping and the opposite on the turns.

After wrapping, I used DEI's high temp silicone coating to seal the wrap and make it less likely to absorb liquids. I used the entire can to be safe.

Oh and most important wrap it as tightly as possible or it will eventually slip and make gaps. Not that it happened to me but that's what happens.

-RyanG

[cjd]

Originally Posted by vividracing

if you get oil on tan wrap

That strikes me as a fire hazard...

[lamawithonel]

Originally Posted by vividracing

<snip>

After wrapping, I used DEI's high temp silicone coating to seal the wrap and make it less likely to absorb liquids. I used the entire can to be safe.

Oh and most important wrap it as tightly as possible or it will eventually slip and make gaps. Not that it happened to me but that's what happens.

-RyanG

Listen to this advice. I know I mentioned tightly wrapping can introduce stresses, but it's really not an issue on most headers-- at least the ones worth owning.

Sealing the wrap is also important. Besides sealing out moisture and oil, it will also help hold it in place and keep if from fraying.