exhaust heat wrap

[johny]

Ive been given some exhaust heat wrap tape and Im wondering if theres any point using it on the stainless downpipe of my Vitesse. It has the standard cast iron manifold so cant wrap that but would installing it after the flange reduce under bonnet heat/noise or will it just smoke, crisp up and disintegrate?

[Iain T]

 I'm not a fan of wrapping exhaust pipes on road cars as if worked hard the pipe overheats and disintegrates. A friend of mine with an MGB V8 wrapped his manifolds and albeit he has a very heavy right foot the pipes didn't last long. 

Iain 

[johny]

Thanks. Ive heard of that for cast iron manifolds but stainless has a higher melting point so I thought it would ba able to withstand the increased temperature...

[Pete Lewis]

i put wrap in the box of Must haves you dont need 

My 1600 had a unwrapped 631 and would tick over for an hour on MOT and never missed a beat 

there are many that have had pipes degrade under the wrap

wrapping a down pipe will transfer any heat loss to the rest of the system 

save some hassle and have a cuppa and drive the car more   Ha "

Pete

[johny]

yes I agree, I wouldnt buy it but as I have it already and it looks so cool....🤔

[Pete Lewis]

34 minutes ago, johny said:

looks so cool

have you got a flat cap to go with it  ???

Pete

[JohnD]

I wrapped my tubular manifold, and then after a few years 'cos it looked so tatty  took it off.  Under the wrap, the mild steel was coming apart in long strips, that were almost black.    I thinkl that undert he wrap, the iron goes anoxic, and it changes from corrosion to ferrous oxide to ferric oxide.     Certainly my manifold is several millimetres thinner as a result.  I don't wrap the manifold and it's stayed that way, thinner walled but no thinner.

Anyway, what's the point?    Consider the Space Shuttle.  Made of aluminium, on re-entry it would be heated to over the weakening point of aluminium, so had to kept cooler.   The difference is abut the same as the difference from inside a manifold.    But the Shuttle need SIX INCHES of ceramic tile to maintain that differential.     Proper ceramic coating in the F1 environment of incremental 0.1%s, it might, but is a couple of millimetres of glass fibre wrap going to make a difference?

John

[johny]

Thanks John. Would a stainless exhaust be affected the same way do you think?

[PeteH]

7 hours ago, johny said:

Thanks John. Would a stainless exhaust be affected the same way do you think?

Anything to do with "stainless" steel, is affected greatly by the grade of stainless. Rather than DIY. I went and "stole" this off the web.

Stainless Steel Classifications

The family of stainless steels is primarily classified into four main categories based upon their crystal microstructure.

Ferritic

Ferritic steels are the 400 Grade stainless steels noted for their high chromium content, which can range from 10.5% to 27%. They have magnetic properties, too, offers good ductility, tensile-property stability, and resistance to corrosion, thermal fatigue, and stress-corrosion cracking.

Ferritic Stainless Steel Applications

Typical applications for ferritic stainless steels include automotive components and parts, petrochemical industry, heat exchangers, furnaces, and in durable goods like appliances and food equipment.

Austenitic

Perhaps the most common category of stainless steel, austenitic grade steels are high in chromium, with varying amounts of nickel, manganese, nitrogen, and some carbon. Austenitic steels are divided into the 300 series and 200 series subcategories, which are determined by which alloys are used. The austenitic structure of the 300 series is distinguished via the addition of nickel. The 200 series primarily uses the addition of manganese and nitrogen. Grade 304 is the most common stainless steel.

Austenitic Stainless Steel Applications

Sometimes referred to as 18/8 because of its 18% chromium and 8% nickel, it is used in kitchen equipment, cutlery, food processing equipment, and structural components in the automotive and aerospace industries. Grade 316 is another common stainless steel. It is used in the making of a wide range of products such as food preparation equipment, laboratory benches, medical and surgical equipment, boat fittings, pharmaceutical, textile, and chemical processing equipment.

Martensitic

Martensitic stainless steels are in the 400 Grade series of stainless steels. They have a low to high carbon content, and contain 12% to 15% chromium and up to 1% molybdenum. It’s used whenever corrosion resistance and-or oxidation resistance are required along with either high strength at low temperatures or creep resistance at elevated temperatures. Martensitic steels are also magnetic and possess relatively high ductility and toughness, which make them easier to form.

Martensitic Stainless Steel Applications

Applications for martensitic stainless steels include a wide range of parts and components, from compressor blades and turbine parts, kitchen utensils, bolts, nuts and screws, pump and valve parts, dental and surgical instruments, to electric motors, pumps, valves, machine parts sharp surgical instruments, cutlery, knife blades, and other cutting hand tools.

Duplex

As the name implies, duplex stainless steels possess a mixed microstructure of ferrite and austenite. The chromium and molybdenum content is high, with 22% to 25%, and up to 5%, respectively, with very low nickel content. The duplex structure gives the stainless steel many desirable properties. For starters, it offers double the strength of ordinary austenitic or ferritic stainless steels, with excellent corrosion resistance and toughness.

Duplex Stainless Steel Applications

Designated in the 2000 Grade series, duplex stainless steel is ideal for applications in demanding environments such as in chemical, oil, and gas processing and equipment, marine, high chloride environments, pulp and paper industry, cargo tanks for ships and truck, and bio-fuels plants, chloride containment or pressure vessels, transportation, heat exchanger tubes, construction, the food industry, desalination plants, and components for FGD systems.

The levels of corrosion, in all cases, would be markedly reduced, often to zero. So I guess the answer to your question would be No?.

Pete

 

 

[Iain T]

8 hours ago, johny said:

Would a stainless exhaust be affected the same way do you think?

304 is the most commercially available 'less expensive' tube followed by the higher grade 316. 

As I said my friend wrapped his stainless tube bunch of bananas manifolds and exhausts on his V8 and it all disintegrated over a short time and not many miles. 

Iain