The turbo housing has been ceramic coated too.

I had my rotor faces ceramic coated, too. I had Swain do it for $150 each. I did it in hopes of increasing engine power output on the principal that the less heat you lose to the combustion chamber walls, the more power you will make.

Rotaries have a large surface area to combustion chamber volume ratio, and that is perhaps the main reason they don't get very good mileage. I guess I am hoping for slghtly better fuel mileage, too, but more power was my main goal.

That will shift some additional cooling work onto the normal cooling system (and reduce the load on the oil cooling system). I'll be running some NPG+ coolant and will pay close attention to radiator ducting and other cooling-related issues. My car will be used for open track days, so cooling is important to me. I'm switching to a front-mount IC now, too, so I will have to keep a close watch to make sure the cooling system is up to the task. If I need to make some adjustment, I will. I'm not an idiot, and I will do what it necessary to make it work or change the setup if it comes to that.

There should also be more heat going out the tailpipe. I will be using a turbo with an Inconel turbine wheel, so I hope that will prevent any chance of turbine damage. The Inconel wheel is just a fortunate coincidence for me, though -- I didn't seek out a turbo with an Inconel wheel. I would expect a "normal" wheel to be fine, too, so long as the tuning is reasonable.

Avoiding carbon build-up seems to be a benefit as well, but I am not sure how much it will help. It wasn't really a problem for me before AFAIK, so the improvement might be pointless for my purposes. If it really does reduce the chance for detonation, though, that seems like a nice benefit.

I have had my rotor faces "dent" in the past, but I believe it was due to running too lean for track sessions, or my J&S going wild (falsely or otherwise) and retarding the ignition too much. Even though this issue was more of a tuning problem than a "real" issue with the rotors, I am attracted to the extra protection the ceramic coating may provide.

My rebuild is still in-progress, so I don't have any results yet. In reality, I am changing so many things ("R85" turbo, "20B" IC, ceramic apex seals) that it will be impossible to clearly identify the effect of the ceramic coating in my dyno results. Perhaps a change in my fuel mileage or significantly better dyno results than cars with similar setups would be enough to suggest that the ceramic coating has helped, but I don't really expect the differences to be that noticable. Ultimately, I want my car to run well more than I want to collect solid data on the effect of a specific change. It is still fun to experiment a little, though, even if the benefits won't be crystal clear.

At least we might discover that its okay to have an additional 0.002" of coating on the rotors for engines in the medium power range without them hitting the housings :), or not :(.

-Max

ceramic coatings on a rotary don't prove a benefit to me. you are putting more heat in the area that is fragile. the aluminum rotor housings expand greater than the cast iron side housings and when they expand too much they get crushed. the only benefit would be spinning the turbo up faster IF that is where the heat is going. i would be concerned about the ceramic coating chipping off and flying into the turbo, etc. i see an increase in the stress put on the already inadequate cooling system of the rotor housings, the water jacket area. which will decrease the life of the rotor housings by means of increased corrosion due to the increase of heat in the area. the excess heat may contribute to detonation in my opinion. as far as carbon build up on the rotors, why don't you take care of that with a water injection system?

remember, people who have something to sell, will try to sell it to you in any way they can. they want to make money.

WOW Max!!! I rememeber asking you about the apex seal debate. I went with 2mm ceramics. Did you go with 3?

can't wait to see an update on your website!

fuel mileage should be easy enough to see a gain in, and it would be welcome too!

So you have coated the turbo housing also: FURTHER the effect of funnelling more heat on the exhaust blades. It APPEARS to me all you will accomplish is to add more heat to the blades and the end result will be blade failure. I am not wishing you ill will, but your TOP FUEL engine analogy has NO PLACE in this application. A TF HEMI only has to function ~ 75o REVOLUTIONS [UNDER LOAD] before it is torn down. Lots of products have a viable racing application and have no application on a NON race car. Just because they advertise something does not mean its true.

The Basic premise you have overlooked is :

Qin = Qout

Rejecting the heat from one component means the heat has to go elsewhere. You have not increased flow rate. All you have done is add a larger heat sink (Koyo rad) and eventually you will reach equillibium.

Well, most of us don't know the answer for sure.

But only a few of us are willing to take one for the team so that others can learn.

I'll post any new developments on this matter, good or bad.

No is is knocking you for being willing "to take one for the team". We are just trying to insure you have thought this thru instead of listening to "majik voodo hype"

if you coated the plate would te coating old up agaist the side seals running on it for 10k+ miles? How the stock housing get i dont see why ceramic could hold up.

other than the turbine issue, why not coat the housings also? wouldn't stand up to seal travel? i know it would reduce water cooling also, but it seems like you would reduce the need for it if all the heat is going out the exhaust.

well naturaly if the heat wont go in to the rotor it will go in to the housing (coolant) and the exaust.

I dont know about that. Lets go back to high school physics. What do things do whent hey get hot, expant that right. So when the exaust gasses will get hotter they will expand more, take more volume, so you will be pushing a higher volume though the turbo exaust housing. And since the same amount of gasses still have to get out, except now they take up more room they will have to get out faster, because there will be mor epressure from behind form the eminating exaust because it take up more room now. And that will result in faster spooling of the turbo.

Also same thing within the engine. You will get more bang for the same amount of fuel and air because you some of the heat that was to go int o the rotor will go in tot he coolant but some out in to the exaust and that prosses will still have to happen int he same time frame but there will be a larger voluem so the rotor will be pushed with a greater force.

so in the end:

-faster spool times

-more power for the same amount of gas/air

-you will have better mpg because you dont need to put as much air/gas in to the engine to get X amount of power. Unlese you drive it at max power flooring all the way, in which case your mpg will stay the same but your peek power will be greater (as well as everywhere else in the powerband)

Yep, that pretty much sums it up.

Increased density charge per combustion event.

we agree with you about the faster spool time etc. epion2985. we are saying when you increase heat you can cause problems.

what about this school of thought?

If I run 13psi with ceramic coated rotor faces, exhaust, and intake would the amount of efficiencies be equal or greater to that of a 14psi engine without ceramic coating?

and would the heat issues be about the same?

Just a thought.

You guys are correct about better fuel burn and mileage with ceramic coating but you are also keeping the combustion chamber hotter which will increase your chances of detonation.

no. detonation is caused when the air/fuel mixture ignites prior to the spark plug firing. This can occure because of two things, temperature and high preasure. When they get too high , one or the other or both the mixture ignites without the spark plug.

Now the pressure doesnt change, but the temperature does here, But , for detonation to occur the high temperature has to be present in the combustion chamber prior to the spark plug firing.

The ceramic coating makes sure the heat doesnt get absorbed and stay there, but that it leaves via coolant and exaust. So it is not absorbed and radiated back when the fresh mixture comes in, possibly causing detonation.

hence why people say it reduces hot spots. Which are places in the combustion chamber where the ehat gets absorbed and is radiated back out naturaly, creating a hot spot.

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kmon guys, you should know better then that. You cant make more power for free. Pretty much nothing in your car can be dome that will improve power and wont cost you something.

However, there wont be MORE heat. There will still be the same amount. Its just that the heat that the ceramic coating will prevent from being absorbed in to the rotor will go other places, coolant and exaust. So the temeratures of those two will rise. So you deal with it by getting a better radiator and shild your exaust system either by wraping or ceramic coating it. Get a ceramic wool stuffed muffler so it wont burn out and get the exaust housing on the turbo ceramic coated and the exaust turbine wheel (or get an enconel one).

So what did you expect, preformance comes with a price. You make more power you need better cooling, fuel delivery, parts that can withstand the stress, etc. This shouldnt be new to you guys.

So since the coolant temps will rise with this mod, did you ever take any measurements in how much your temps actually increased to give us an example?

the weird thing is that the coolant takes longer to rise and hoovers around 84 Celius on the PFC.

try a google search. detonation and preignition are different. preignition is when the air fuel mixture ignites early, almost like setting the timing way advanced, so the peak pressure occurs too early.

detonation is when the air/fuel mix actually explodes. this is why its so destructive. normal conbustion is a slower burn. detonation is partially caused by charge temps, which is why intercooling is a big deal

could a car detonate from the air being too cold?

for example getting on it when it's cold.

boost is higher when its cold....

Do you mean cold motor? Colder air is denser so it boosts more and its more air technically for the same boost.

detonation is when there is 2 flame fronts in the chamber. it is causes by increased pressure in the chamber after the sparkplug fires. the burning gases expanding cause the pressure to increase, this pressure increase can cause the fuel to spontaneously ignite in another area of the chamber.

pre-ignition happens before the spark , it is not as bad because the chamber is not at maximum compression. usually started by a glowing piece of carbon or sharp metal point.

well I misworded it a bit, did make it sound like pre ignition. But it doesnt matter because like you said, and like I said high tempetatures and pressure.

Dare I put enthisis on "glowing piece of carbon or sharp metal point".

Sharp point, well there are two things here. One sharp point means its thin and gets heated up easy. Like putting a needle in a fire it will turn red really fast, first at the tip.

As far as pressure goes, Pressure is the force acting over an area and is calculated from the equation,

PRESSURE = FORCE / AREA

The unit of pressure is the pascal (Pa); it equals 1 newton per square metre.

The greater the area the force acts over, the less the pressure. The smaller the area the force acts on the greater the pressure. Hence at a sharp point very high spike of pressure can occur.


Glowing peace of carbon = hot = hot spot in itself. Prevent hotspots and get a smooth surface and you reduce the risk of detonation. Which is what ceramic coating does to some extent.

[QUOTE] The ceramic coating makes sure the heat doesnt get absorbed and stay there, but that it leaves via coolant and exaust. So it is not absorbed and radiated back when the fresh mixture comes in, possibly causing detonation.
[QUOTE]

Huh??? Where did you pull this stuff from? References? Nothing in my experiance and training as a combustion engineer comes close to what you just described.
Everything I have read in the SAE/Mazda research papers suggest that for sustained high rpm use, the key to better performance and reliability is to increase heat conductivity not decrease it. How can a ceramic coating ensure that heat won't "stay" there but that it leaves via the coolant???? Heat removal is most dependent on the cooling surface area in the water passage and the surface area of the rotor (oil cooling). You put an insulating material on one, you just trapped more heat, period.