Header: Stainless vs. Mild

[Whizbang]

as far a moisture goes, i believe the area you reside would play a huge role along with WHEN you drive your car. If you take it out in the rain and often i can see it being a problem. But if you live in New Mexico and rain is rare im sure its not a need item.

[classicauto]

FWIW, I've had a downpipe and turbo manifold wrapped on my car for 3 seasons. The manifold back then was a greddy log, downpipe was stainless from ATP welded by me.

My friend has a set of (mild) headers on his 340. We wrapped them 6 years ago (first things I've ever wrapped) and they are still on the car doing fine.

I honestly don't know why people are paranoid about moisture.....there'll be more moisture INSIDE your exhaust from heating and cooling - we've all seen the little puke out. Anything getting on the wrap (which BTW, most companies recommend wetting it before install so you get a tight wrap) is going to burn off because of the SMOKING hot exhaust

[RETed]

In regards to wrapping...
It's not the moisture that causes problems.
It's the fact that the temp of the metal increases significantly due to the wrap.
This tends to kill WELDS first.


-Ted

[My5ABaby]

Originally Posted by RETed

In regards to wrapping...
It's not the moisture that causes problems.
It's the fact that the temp of the metal increases significantly due to the wrap.
This tends to kill WELDS first.


-Ted

Good info.

With wrapping, has anyone had issues with RB headers? Or have any testimonials?
From everything I've read they're solid headers with good welds.

[Whizbang]

at the same time, rapid cooling is more likely to cause cracking than to high of a temperature. The wrap will remain the heat longer assuming its PROPERLY covered. Usually people have exposed areas, and these will cool much faster than the wrapped areas which will develop stress cracks over time in the thinner steel. You CAN have such a thick steel that stress cracking can't occur but that concept is not practical for the topic at hand.

A ceramic coated SS header would probably be the best bet overall.

[JunpoweR]

The moisture evaporates from the headers heating up.
I don't see how it can stay logged inbetween the wrap and header.
Fiberglass and Ceramic preg Fiberglass wrap (Do not use anything but Ceramic/Fiberglass wrap for rotarys)cannot trap water if you heat it up and while driving even if water gets onto the wrap it will evaporate in seconds due to heat.
I can imagine having wrap around mild or SS can reach higher tempatures, remember, when almost any type of metal is heated up it expands to a certian point and if overheated it will shrinking more than it expanded causing cracks and warping. All this is caused by many different factors, Pipe gauge, weld quality, material choice. Exhaust wrap is old school technology, get a good quality coating from JetHot.

SS304 had many advantages over Mild Steel.
Lighter - Stronger - Higher Temp and Corossion resistance.
The only advantage I can see that Mild Steel has is it expands and shrinks better because is is a softer steel than 304SS.

The only other way I can imagine why water would be a problem is when your headers are very hot and you hit a puddle and water splashes onto the hot exhaust metal cooling it down to fast causing warps and cracks in welding. Remember the weld is always harder than the metal around it. During welding, a filler rod is used causing the weld to cool and introducing a new alloy into the welding pool making that area harder than the steel being welded together, thus less expansion/shringage in the welded areas causing cracks and warping in those areas.

I would go with SS and JetHot Coatings.

StarSpeedRacing will be making SS304 Medium Primary Header and Mid pipe Combo that bolts up to any bolt on cat back, check out the GB section soon.