Ceramic coating intake manifold

[Joshstix]

I have been designing a new intake manifold for my 3S and have got to the stage of thinking about thermal issues. I know ceramic coating exhaust manifolds is common practice but I haven't seen it done for intake manifolds. The stock 3S maifold on my engine at the moment often gets to 50-60 degrees on cruise and in traffic which is hotter than the intake air travelling through it.

Now I know I could make a thermal barrier gasket which works reasonably well. The thing I don't like about that is my engine is already making a truck load of heat in the combustion chamber and as far as I can tell the intake manifold is a fairly significant heat sink hanging off the side of the head. Stopping the manifold from heating up would in theory cause the head temperature to increase, which I don't think is optimal.

So my theory is to get the inside of the intake manifold coated with a thermal barrier coating and then potentially also coat the outside with a thermal dispersant. My concern with this plan is I really don't want to go pumping pieces of ceramic coating through my engine and turbo if it comes off the manifold.

Has anyone seen this done before or would like to add their idea's?

[TA-022]

I thought the ides of ceramic coating on a exhaust manifold was to keep heat in and not affect items around it etc.

So wouldnt this be bad on the intake side seeing as cooler intake is preffered? By coating it i believe you would raise your intake temps.

[Joshstix]

The idea is to keep the heat from going from the hot area to the cold area. On the xhaust side that is the exhaust gas to the manifold. On the intake side it is manifold to intake charge.

The idea is to keep the heat out of the intake charge by putting a thermal barrier coating on the iside of the manifold.

[Squid]

I would have thought that intake temps were most effected by convection from the head/ports/valve area, and the metal was reponsible for removing heat, not adding to it... But I can see what your getting at, just don't know if it would work...

Make 2 manifolds, dyno test them, temperature test them, give me the one you aren't happy with and I will either coat the inside or remove the coating depending on your test results!!

I am interested in your 3s intake manifold design tho, it is something that disappoints me when I look at the 3s and I don't like everyone's answer of up the boost and shell be right... there are gains to be made, and if they can be made at lower boost, that is better!

[TooF]

im not sure if you are on the mr2yahoogroups mailing list but a similar issue came up recently in terms of thermal barrier gaskets/spacers.

im not convinced how much heat is actually dissapated to the inlet charge air via the manifold.

the inside of the manifold has a relativly small surface area in terms of a heat exhanger. and also the residence time of the air in the manfiold isnt exactly all that long.

id be skeptical of just how much heat the manifold delivers to the air flowing though it.. dont get me wrong provide some testing numbers or some modelled numbers that suggest otherwise and im happy to accept them.

i just have the thought that you might be chasing your tail over an almost nothing ammount of heat (when compared to heat from the compression of the air)

[The Real Roadrunner]

fenolic spacers seem to work well on some of the eurotrash i have come through here but not shore on a 3s.
ben ellis had the inside coated black on the pipes and intake on his 1jz
just make sure you use a reputable coater as i have heard of coating flaking off.
ceramic vs pistons and bore i know which one will win.

[TA-022]

my bad didnt realise it would be internal coating

[thechuckster]

phenolic spacer plate and a re-think of air flow in the engine bay would be the way to transfer of heat from head to manifold.

Given the low mass of the air charge and the limited surface area inside the manifold, coating it isn't going to do much unless the car is a peak-hour commuter car (low speed heat soak).

My setup has the manifold and plenum going over the top of the engine to right next to the turbo - it's the stationary heat soak that pumps up air temps. Once underway, or with significant air-flow speeds (e.g. rmp over 2k or boost at any speed) the heat-soaked manifold isn't much of an issue except for assisting vapourisation of fuel (from poor injector placement).

Given that most of the heat comes the turbo, its the performance of the intercooler that you should be focussing on (imho).

[Joshstix]

Given that most of the heat comes the turbo, its the performance of the intercooler that you should be focussing on (imho).

A big hit of boost pulls the manifold temperature down significantly. Now this tells me two things:

1. The manifold is hotter then the air that is going through it
2. There is a substantial transfer of heat from the manifold to the intake air.

I guess I'll just make up my own mind on this one and decide if the benefits are woth the money invested.

[ivan]

From what i have been informed, these guys have made a few for 4EFTE engines and for the 3SGTE engines.

http://www.outlawengineering.com

The starlet ones were about 100US for both inlet manifold and throttle body, and just the inlet manifold were about 60US.

Ivan

[30psi 4agte]

Its Fairly common practice to coat inlet manifolds. This is especially usefull to the V8 guys where the manifold sits on top of a hot engine block and between two hot heads.

Josh: In you situation with the 3s designed the way it is, It would prob be a good advantage to give some sort of barrier and keep the heat soak effects to a minimum.


Give " Ceramic coat Australia " a call here in S.A . He will beable to give you a more indepth reason as to the major advantages to it.

The guy (forget his name but no him by face ) is an absolute champ and i couldnt speak more highly of him.

Their web site goes into the benefits abit better

(08) 8354 2066

http://www.pacemaker.com.au/ceramic_coat.html

[3t-RA40]

Josh, also have a chat to Stuart @ Procoat Ceramic Coating - Unit 1 / 1 Clare Mace Cres, Berkeley Vale NSW 2261 02 43889946 or 0407895044. Real nice guy to talk with and also sponsors Shane 1JZ 747's Cressida. I was talking to him during the week about my new turbo exhaust mainfold I just made.
Cheers,
Neil.

[Screamn_Sleeka]

You need to keep the intake manifold interior course, if the ceramic was smooth you with get the fuel disasociating from the air.

Coating the outside would achieve the same effect for what you want, dont know if it will work how you want though.

[Steve M]

coating the outside only surely would keep the head/valve heat inside manifold and so it would transfor to the air = what you're trying to avoid here.

Coating the inside only would keep the head/valve heat in the manifold too, but would allow it to transfer the the athmosphere where you'd want it to go.

Keeping the inside rough would provide more surface area and so might result in a raised inlet temperate. It might also slightly sow down the air's passage and so would allow more time for heat to transfer from the manifold to the inlet air, thus compounding the surface area problem.

[thechuckster]

the key to the problem is how does the heat get to the intake manifold?
-thru it's connection to the head
-from the heat in the air charge coming form the turbo
-radiant heat in the engine bay (from the bock and the radiators)

So the solutions might be:
-an insulating space between head and manifold
-more efficient intercooler
-improved/modified engine bay ventilation.