Ceramic Coatings - Dumps and Front Pipes.

[GTR_JOEY]

Cool thanks for clearing that up for me GTSboy, Abdul did say that everything will need to be extensively cleaned before its coated so I will ask him to pay particular attention to the exhaust housing

[djr81]

Has anyone seen the stainless actually crack or it crack along the seam weld? I have only ever seen them crack in the welds.

Frankly depending on what manifold it is I wouldn't have a problem wrapping them as long as you put some thought into it. Every cracked manifold I have seen has been a tubular manifold with welds with no/poor/inconsistent weld penetration. Never seen a manifold made from stainless pipe (vs tube) crack. The wall thickness is the cheap insurance and reason why people have far less issues with mild steel. IMO stainless is actually superior if done right

Mine warped then cracked. So it was a matter of which caused the failure first. Will have a look to see where it cracked but would guess a weld.

FWIW I have no faith that such a thin coating of ceramic does anything to restrict heat transfer. There is a reason we use massively thick refractory on our vessels.

[GTSBoy]

FWIW I have no faith that such a thin coating of ceramic does anything to restrict heat transfer. There is a reason we use massively thick refractory on our vessels.

The skeptic in me agrees with you. The engineer in me cannot see how such coatings can change the emissivity enough to reject radiation input and also reduce the convective heat transfer coefficient and also how such a thin coating can provide a simple amount of insulation by being less thermally conductive than the parent metal underneath.

However, I have seen for myself that it works, so I take it at face value. Just keeping the oxidising/reducing gases off the surface is often worth the price of admission in itself (in our industrial applications). The ability to reject some of the incoming heat can be the difference between a part failing and surviving too. I have to keep my skepticism in check when it comes to this stuff.

[The Bogan]

Russian container ship I went up to Weipa in had a lagged exhaust and a turbo beanie. LOL.

I would assume that its not the only plant to utilise lagging, hell I've seen more lagged steam pipes and other hot liquids and gases when I was working at ICI.

The furnaces had some white brickwork around them though, tried to re-locate some for a BBQ but then thought better of it as I thought they may have asbestos in them.

Ships turbo was the size of a small car.

Ive also seen lots of top race cars with it so I would assume it does something.

Whoa, that's 2 assumptions.

[GTSBoy]

Um....diesel engine exhaust temperature much lower than petrol engine exhaust temp.

And diesel engines are not what I meant by "industrial plant". I'm talking about real industrial plant with furnaces and 1000°C preheated combustion air and 2500°C flame temperature and 1200°C flue gases and 500g/Nm3 dust loadings of horrible, corrosive, abrasive dusts. Like cement plants, lime kilns, alumina plants, glass furnaces, hot gas generators, hazardous waste incinerators, boilers, waste heat recovery generators, etc etc.

Race cars are toys by comparison, regardless of the fact the environment inside the exhaust being horrible. It is the very fact that it is horrible that defines why we don't externally insulate steel (or even stainless) pipes and ducts when what is inside them is hugely hot and horrible. The simple fact is that on a "top" race car you drive it around for a few minutes on a weekend then you take it apart. You throw away that which is f**ked and replace it. On industrial plant we want it to work for 8000 hours straight between shutdowns. I never said that turbo beanies (as a specific example of external insulation) don't work. I just said that they are not suitable technology for the real world. They're only suitable for non-important stuff like cars, due to the consequences of using them.

[The Bogan]

When I say plant I meant big motors for ships, generators and pumps and stuff, not a furnace.

A cars exhaust will not see anywhere near the conditions of a industrial furnace I would assume, so they really shouldn't be compared.

I acknowledge your experience in the trade but are we not talking about two totally different situations and uses.

As for the consequences of using a wrap or other form of lagging, I have wrapped every manifold I have ever had over the last 35 years of driving and have never had a issue , I was told to wrap them by my old TAFE teacher who was a motor head in 1980 when I did my apprenticeship.

[djr81]

I do agree that high quality stainless pipe with good engineering should out last the life of the car.

CSB time. Inconel exhausts wear from the insides out. So the thin wall stuff you see on race cars has a very finite life.

Edited January 6, 2015 by djr81

[Griffin]

Lagging your car exhaust cause you saw it on a diesel ship is like putting venetians on your vl because they were on your nans house in the 70s

[niZmO_Man]

Lagging your car exhaust cause you saw it on a diesel ship is like putting venetians on your vl because they were on your nans house in the 70s

People do that you know...

[mattie4270]

Im very experienced in all exhausts,all cars,wrap it is the go,and intercooler pipes too.Just look at proper race cars

[sucram]

Going to get the gate pipes done as well, as discussed I don't think it will make much of the way in performance gains but im really only trying to stop the radiating heat.

Sucram im just doing up to the cat for the moment, then once its running again ill get the rest of the system done. Im also getting the gate itself done (not the diapgram part) but the part where the gasses flow,once again to reduce radiating heat.

Wont do much, but your basically only paying for the materials so you may as well get it done.

If you leave the exhaust, you probably wont get it done, just like I have constantly put it on the back burner.

FWIW I have no faith that such a thin coating of ceramic does anything to restrict heat transfer. There is a reason we use massively thick refractory on our vessels.

I couldn't get my head around it either. Until I needed heat management on a bike as it was basically unrideable in summer or any period of traffic, with leathers on. Coating made it a non issue even in shorts!

From what I recall, the inside layer absorbs/reflects some heat and the outside insulates or contains it. Its about slowing down temp spikes which reduces the surfaces overall and peak temps. Once coated you might notice that it stays warmer for longer. This is why I never get my intake coated because in my mind I think it will be heat soaked for longer and hotter which is debateable.

On a ship the engine is inside which I assume has little air flow, so insulating is the only option. If you have a flange that is 1 foot thick I doubt you will warp it and im guessing housing walls are really thick too. Also, the insulation used in industrial might have the initial thinner layer quite loose and then a tightly packed secondary layer.

Compared to a turbo beanie in a car that is randomly and tightly packed, along with heat cycles you get the same effect of layers peeling off on the housing. Where industrial might run for days/weeks/months and with room to have massively thick layers. Even when shut off might be a few hundred deg C for days. This relatively low heat cycle might be maybe 2 dozen in its life time. Most industrial/ship engines run at a constant load and relative heat unlike a car which sees wild temp spikes in short periods in comparison.

Don't get me wrong, im not anti beanie, as they do work and work very well. Its just the toll they take when directly on a housing. On a low mounted turbo rotary you have no option but to use one as its so close to the intake. But back then there wasn't any real heat shields available. So now you can run housing, air gap, heat shield, benie or insulate and then intake manifold and basically no heat cycle fatigue.

[Daleo]

I used to a bit of fab work for the original owner of J&J Performance (now sold & renamed hyper coatings), and also got to seeand participate first hand in the prep and application of all sorts of perfomance coatings.

*Please note; This is not an endorsement of Hyper Coatings*

As has been said; all parts are scrupulously bead blasted, then baked at 250deg for 3 hours; this burns off any residual oil or contaminants. It also tends to show up and cracks that weren't visible in the cleaning process.
They are then re-blasted, and coated. Most insulative and reflective coatings have a primer that is baked, and cooled; then the actual coating goes on, and is baked yet again.
Polished finish (chromex) starts as a satin silver and is then put in a ceramic ball rumbler; which is like a huge plastic tub filled with 3mm dia ceramic balls and a water/detergent mix, and get vibrated violently for a few hours until the balls burnish the surface and makes it shiny.

I was fortunate enough to be able to coat my turbine housing (inside and out) my dump pipe (inside and out) and my midpipe (outside only, due to the risk of damaging the catalytic converter). Mine is the satin black (not chrome) finish, as it was much stealthier IMO. It is super fragile until it has been fully heat cycled; so you hve to be hyper vigilant when fitting parts initially, as you can destroy the coating easily.
Previously, all pipes (304ss) were lagged for around 2 years, and when the wrap was removed; the pipes were perfect.

The coating reduces skin temperature just as effectively as the lagging did, but it looks 11ty billion time neater than lagging; which reminds me of a 1st World War soldiers leggings. It always ends up scruffy and fluffy after a while, and if you get oil near it; it smokes for weeks.
I've noticed that the coated parts also shed heat much faster one the car is switched off.

As for bits flaking off and destroying turbo's; thats just stupid. FFS; people coat piston crowns, valaves; combustion chambers, and exhaust ports!
My mate did a lot of work coating Wankel rotors, and rotor housing as well.
The coating is less than a thou thick; and just doesn't "flake" in the manner that you're imagining; it scratches off like a powder.
If your chosen coating provider won't coat turbine housings; it's because they have no faith in their ability to prep and apply the coating.

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[The Bogan]

Some good info here from first hand experience on the subject, also some uneducated waffle because SAU.

matte4270 should tell the owner of this 32 that he is doing it wrong

See you at work some time Joey.

[Griffin]

Would you like ice cream with your waffle?

[The Bogan]

OK Griifin, Ill bite, what do you suggest, and what is your experience with coatings and wraps?

Im looking forward to your reply

[GTR_JOEY]

See you at work some time Joey.

I'll be around for another year or two mate, I'll pop around when the cars done

Thanks for that write up Dale, very informative

[GTSBoy]

Some good info here from first hand experience on the subject, also some uneducated waffle because SAU.

matte4270 should tell the owner of this 32 that he is doing it wrong

See you at work some time Joey.

The f**k are you talking about? I see reflective wrapping on intake piping. That's cold air. That's trying to stop the heat getting IN. It's arguably a waste of time on the turbo outlet pipes unless they have a clear view of hot exhaust components (which they probably do, on a GTR) because the air inside the compressor outlet pipes is possibly hotter than the engine bay air.

What I see from you is someone who doesn't actually understand the science. That's alright. We have people paid to do that for you.

[The Bogan]

Yes it is heat proofing GTSboy, whether it is for keeping heat in or out its still a form of lagging/wrap.

The years I spent fabricating sheet metal to hold lagging on all sorts of pipes caring all sorts of fluids and gasses must have been done due to the engineers that designed them not knowing the science behind their work.

I didn't design the insulation systems, I just use to built them.

I apologise for trying to bring my experience to this thread because you obviously know it all.

Enjoy your awesomeness.

[GTSBoy]

Enjoy your awesomeness.

I take this pearl away from your post rather than succumbing to a fit of facepalm.

[Griffin]

I'm all for coating the manifold, turbine housing and dump.

I won't wrap exhaust, if it's too close to another component I would shield that part first.

I also have wrapped and covered in foil tape intake piping and intercooler return pipe depending on the situation as said earlier to keep the hot air out.

I have just replaced and upgraded a gt35 on a gu petrol patrol where beanie, heat Wrap braided lines cooked everything. It all went in the bin along with the near new turbo but that's another story.

People seem to like touching turbine housings straight after a drive cause they radiate nowhere near as much heat after being coated.

That's just my experiences though.