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I'm not interested in proported performance gains. Heat is the real issue as it can adversely effect reliability and longevity.

Regarding wrapping the cat, Thermo Tec believe its fine and I have read in another thread that its acceptable and actually improve the emissions performance because the cat reaches operating temperature sooner.

Edit: Quite the contrary of what you have said regarding exhast gas flow, I have also read on numerous occasions that its advantageous to keep the heat in (again, this goes back to the proported performance gains).

thats fine if your treating heat issues, i was just trying to inform you.

thats true it will bring on the cat up to temps sooner and improve emissions in that regard, but lets get real here, you have a skyline and your an enthusiast, are you really concerned about emmissions ?? :laugh:

overheating a cat does occur from a rich mixture of fuel burning inside it, which can damage it. your doing the same thing by insulating the heat inside the cat, im not saying it WILL overheat and cause damage, but it CAN, and your helping that cause with insulation

in regards to performance, ive given a reply to rev210's post, so refer below

The performance gain comes from retaining the thermal energy inside the pipe. If you can retain the engery in the pipe the velocity of the gas increases as it has more energy. Cast iron is better than mild steel uncoated in this regard. Quite a good idea to coat the exhaust turbine housing and then turbo beanie it too.

a performance gain is only achieved by retaining energy/heat when you STILL want to use it. such as in the exhaust manifold, because we still have the turbine to go through and pass on the energy to it to spin it up

after the exhaust is passed through the turbos turbine, it is waste, and needs to be expelled as soon as possible, with the least amount of restriction/backpressure to give the best pressure differential accross the turbine to give the most power, this is agreed on, yes ?

the second point, is that velocity is NOT increased, rather it is maintained as best as possible by retaining the heat in, to say that velocity increases at this stage would mean we are adding energy in at this stage which is not true.

now back to exhaust gasses being waste matter after the turbine, the goal is to get rid of this waste gas as quick as possible, by moving the most amount of mass through the exhaust as possible with the least amount of back pressure. now any given diameter of pipe ( eg 3") will flow x volume of gas with a certain amount of back pressure (eg. 300cfm with say 2psi back pressure) , by changing the density of a gas we increase its mass for the same amount of volume, thus we are moving more gasses through the same pipe with the same amount of backpressure. by allowing heat to escape through the piping into the atmosphere, we are decreasings its temperature and thus increasing its density.

Edited by mokompri

Yeah and by increasing its density we are increasing its mass, and thus it looses momentum and slows down = more backpressure :P)

I like the idea of keeping the heat in preturbine, cos the hotter it is, the more energy available for the turbine to extract. Cos remember the pre/post turbo EGTs are upto 300C difference or even more.

a gas with a higher temperature has a higher pressure for the same volume though (3" pipe) and thats what causes back pressure, so reducing its temperature will reduce its pressure and thus you should have less back pressure.

im pretty sure kinetic energy and heat energy are seperate at the molecular level though. heat > excitation of electrons/changing of electron orbit, kinetic > movement of the atom as a whole. so heat doesnt affect its kinetic movement directly, unless i got something wrong there?

the speed of the gasses will be a result of the volume to cross sectional area of pipe relationship. the drop in speed will be because there is less volume in the denser gas to go through the same size pipe. its mass we want to move not volume.

think of it this way, a 3" pipe will reduce exhaust gas speeds because of the larger diameter over a 2" pipe, but we know which one gives more power and less back pressure. speed isnt really a governing factor in removing gasses from the exhaust, its mass ! move more mass, you have less restriction

Edited by mokompri
First just a note to say when I said 'increases gas velocity....' I meant over the non-insulated systems gas speed, because no one has suggested the cover secretly adds energy itself.

You know what happens when we heat water (molecules)?

Or let me put it another way.

What happens to the speed of water molecules when they lose heat (are cooled).

What happens when you take oil or honey and try and pour it through a pipe both cold and then heated?

by definition the word increase is wrong though, relative to a non insulated type, it simply maintains the velocity it has - but i get your point

yeah when you heat water molecules, or any molecule for that matter, it vibrates and moves apart from other surrounding molecules (lower density), the more you heat it, the more it vibrates. 0 degress kelvin which is the lowest temperature, is when molecules stop vibrating all together, thats why you cant go any colder by definition - it has nothing to do with the speed/velocity of molecules through space, its a stationary vibration in a way.

what happens is, that you get a different viscosity, and a lower viscosity fluid will flow thinner and faster through a cavity, BUT this is verryyy different to how a gasses work. viscosity doesnt apply with gasses, it doesnt exist. a gas with a pressure above atmospheric will expand until it either fills its space, or equalises with the pressure surrounding it ie atmosphere.

Edited by mokompri

i dont see anything wrong with a little discussion, if you feel your not up to it, then dont post.

im sorry which part of it am i incorrect about because you didnt specify, your link states nothing different from what i said.

your taking my use of the word stationary in the wrong way. what my point is/was, that the vibration of molecules is far different from its movement through space (in gas form), and there not interelated, where as you implied they were.

OK so your NOT talking about viscosity when your talking about pouring honey, when its hot or cold, then please explain what your point was.

and yes density does apply with gasses, but in liquids density and viscosity are related. its obvious that honey flows more freely when hot, this is because of its lower viscosity, which is also because it isnt as dense. the same does not apply with gasses because the molecules are no longer bonded together at all, where as in a liquid they are, and thats where viscosity comes in.

"Like I said I'm not going to add any more to our little debate, it's not really helping anyone else in this thread."

i disagree, if i were correct then wrapping your front pipe or cat converter would seem pretty pointless and a waste of money. if you are correct, then yes there is a performance gain to be had and its worthwhile doing. i think its worthwhile to find out which is the case, so people can make informed decisions

were having a discussion about it, putting our ideas forward and debating the issue - but it seems you would rather belittle me with your greatness and dismiss further discussion, which is what a FORUM is really about, isnt it.

if im incorrect and im happy to be corrected, then please argue your case with self explanation instead of just posting links.

Edited by mokompri

appologies if you have been slurred in any way. Not having a go.

I am going to delete my posts about this since it causes you to take issue.

I would like to strongly reccomend you investigate why many and various forms of motorsport take the trouble of doing this and the reasons why (it is easy to find them with a little google). You will find dyno comparsions before and after and even the physics behind it. I have done this to my cars for many years and I do so knowing that the power is increased.

Lets just say that I don't know why but, I have more than ample proof that it does. I'll leave it to you to be the one to explain it , since you are keen to do so and I am not.

  • 8 years later...

Ok, bit of a thread dig here,8 years ;).. ive done a search but haven't found the info im looking for, if it has been discussed recently please point me in the right direction of the thread.

What I want to know, has there been any further development/ results in regards to pros and cons of ceramic coating manifolds, dump pipes and turbine housings.

I have a full race manifold, twin tial gates, a BW 83/75 turbo and 4 inch dump pipe

Im really looking to reduce the amount of heat in the engine bay and if possible increase performance.

Has anyone got any back to back results?

Reliability issues?

Ive messaged Full race about coating their manifolds so once I get a reply I will report back

cheers

I've ceramic coated the full race manifold on my SR and everything back to the cat......even the intercooler pipes...lol.

Turbo beanie on the ex housing.

Its still like a furnace in the engine bay.

ACL heat shields and vented bonnet would be the next step.

Good info^

How long have you been running it like that? What turbo are you running.

I just rang GCG and they quoted me $265 for a BW airwerks turbo beenie for an s300 series charger

You would have noticed a decrease in engine bay temps even though its still hot.

Got a little bit of info from someone who use to do ceramic coating, he reckons you will generally see a 30% decrease in engine bay temps. He also said he's seen a back to back of a V6 commodore that had its extractors ceramic coated and there was a definite gain in hp on the dyno

Running a GT3071 initially and then a GT3076 from 2008/9.

When i had mine coated it was double coated and inside (as far as possible) and out. Can't comment on whether there was a heat/spool/hp advantage as i had it done from the get go. Suffice to say nothing has melted and paint on the bonnet hasn't bubbled/blistered. In theory, I would expect a spool/hp advantage.

Got my beanie from here (although mine had the Garret logo at the time):

http://www.horsepowerinabox.com/thermal-products/

The beanie certainly makes a difference as you can put your hand on it minutes after shutting down.

Dump pipe would be the next major source of heat but reluctant to wrap it as I've heard this can cause it to "overheat" and cause metal fatigue. Perhaps heat shielding with the ACL stuff.

Edited by juggernaut1

The beanie certainly makes a difference as you can put your hand on it minutes after shutting down.

Dump pipe would be the next major source of heat but reluctant to wrap it as I've heard this can cause it to "overheat" and cause metal fatigue. Perhaps heat shielding with the ACL stuff.

Beanies are great.

I don't know which wankah made up that bullcrap about wrapping stainless, it certainly won't ruin a dump... Perhaps a thin stainless manifold but then you would have other issues.

As long as the stainless is good quality.

I have had my dumps wrapped for 5 years and many trackdays, no issues on the ones I have wrapped for others either.

If I was planning to wrap mild parts I would ceramic coat them first for rust protection.

  • Like 1

Im in the process of doing a full turbo back exhaust. If you're only looking to protect nearby non-metal surfaces, or painted metal, then it looks like only a few select heat shields are needed to keep those surfaces protected from radiation. Hoping to re-use and/or modify the original heat shields (off the front pipe, not the stock dump) for the new bell mouth dump/front pipe. I have some scraps of aluminium ventilation ducting which are made of curved and corrugated, decently thick aluminium. Should make an interesting heat shield material.

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