Bill

Ski,

This is my point exactly.

Stainless cools quickly because it CONDUCTS heat extremly well. Heat that it transfers into the engine compartment. Heat that you DONT WANT in the engine compartment.

The ceramic coatings are a great INSULATORS. Insulating the heat from the engine compartment. Heat that you WANT OUT of the engine compartment. Out the tailpipe where it belongs.

Now we just need to find someone that fabricates exhaust systems for our cars to become interested in the coatings.

Ski

But in regards to the "engine compartment", I could see putting some JH coating on the exhaust manifold to reduce the heat but as far as the exhaust on the side of the turbo down pipe, test pipe,,the actual amount of exhaust piping from the turbo side; that is in the engine compartment is very minimal.

When I replace my turbo next month, one thing I am doing for $89(Thermo-Tec) is insulating the hot side of my turbo and the down pipe to the s.s. pipe flange of the test pipe. I am also at this time sending my nose panel to SFR for Tim to vent for the intercooler.

You may want to take off your exhaust for the 951, take it to a custom shop, have them build it, split it in sections(get rid of the hard crimps)where if you needed to add a cat later for inspection you could. Take it apart and send it JH.

We are all going to eventually do what we want to do because of our own reasoning. But that is why these threads are so intersting,,ideas and inovation. Good luck.

Scott

Just a thought as far as coating the exhaust goes. Someone once told me not to coat the exhaust pipes after the turbo because by keeping the heat in your pipes it keeps your back pressure from dropping. By letting the exhaust gasses to cool you are allowing the pressure to drop in which you allow the turbo to spool up faster. Although I believe this to be true I am coating the exhaust manifold, the cross under pipe the Turbo hot housing and the down pipe. From there back is 3" Stainless with a Borla XR1 muffler. I have used Swain Tec to do my coating so far as they seem to use a better(?) thicker ceramic coating. Just my .02 .

Bill

Thanks Bret,

Just as you say, this is just someting that I have been contemplating and thought I would throw it on the board for discussion.

There is a lot of high quality brain matter that looks at this board.

Scott,

I read an article a while back on the heat wrap products used for insulating exhausts. It claimed just the opposite. It stated that by retaining the heat energy the excited/rapidly expanding gas molecules exited faster, thus increasing the vacuum signal inside the combustion chamber. The faster a hot gas molecule expands, the faster it will expell a colder gas molecule in front of it.

I have no proof of this, but it sounds logical to me.

I dont like the wrap products as they retain moisture, excellerating the corosion process.


Boy talking about hot gas molecules, coupled with the pictures, is getting me excited!...heh heh.

TurboTim

Bill,


Most likely we will not be building exhaust systems in mild-steel.We will Jet-hot coat our 304SS though.

304 or 321 are far superior to mild steel for turbo exhaust systems. Stainless is more resistant to extreme heat then mild steel.It will be less likely to fatigue and crack. This is why we use stainless.Stainless does not dissipate heat like aluminum.So it does not shed heat towards the surrounding areas like aluminum would.

Speaking of shedding heat. Do not coat your intake manifold or other aluminum parts! Jet-hot keeps the heat in! What you are doing is taking away the aluminums ability to dissipate heat. It is this heat dissipation qaulity of aluminum that makes it a desirable metal to use for blocks, heads, intakes and intercoolers, etc..... By coating it, you will have higher temperatures, whether it be coolant or charge air temps.

You want to retain the heat in the exhuast system. Heat is energy. That is why it is beneficial to Jet-hot coat your exhaust. Keep the heat in, keep the energy high. This is what will spool-up your turbo. Once the exhaust leaves the turbo it will start to cool. If it cools too quickly, it will cause back pressure. Back pressure is bad on a turbo car:^(


Tim
86 951 http://www.speedforceracing.com

Ski

I disagree with the intake manifold statement Tim. Jet Hot began for the military to keep heat from surrounding parts on aircraft in 1983, yes to keep heat in and away from other parts; that is the way it started but then they saw other benifits too.

The coating is an insulator. It does not differentiate between hot and cold. If it will keep heat in it will keep cooler air cool. Both interior and exterior are coated, all of mine did anyway. I know you know this but I say this for people who might not be that familiar with the coating. I have my exhaust and intake manifold done on my boat and my Grand Cherokee. The coating is so smooth on the inside of the manifold, after removing any burrs before I sent it, that it almost acts like polish job. Anyway, my Jeep seemed to be a bit smoother after coating but the big difference was in my boat. Whether or not the air fuel mixture got better or what but it just seemed silky smooth and has stayed that way after 6 yrs, not to mention beautiful. If my scanner wasn't dead I'd scan a pic or two. My wife even noticed that the boat ran silky smooth, started even better(it is EFI),,,THAT is a difference! But all that said, I seem to have had good benefits from doing the intake. Like I stated though previously, have a tap set handy,,it also doesn't differentiate on threads either. I put small bolts/nuts and washers over the fuel injector ports on the manifold before I sent it in. Just my own .02
www.jet-hot.com

Bill

Tim,

Good Point!

Stainless does have superior strength to mild steel, so coating the stainless would be the best of all worlds.

Funny how sometimes you don't see the forest thru the trees. You definately improved on my thought.

But then again this is proof how valuable this forum is, and how valuable having guys like SFR participate in the board.

I have found in business that an open sharing of knowledge leads to continued success. And a buisness (or person) that hides knowledge, may have initial success but will ultimately fail.

Make's you wonder about the guys that don't participate on this board....hmmm.

Anyway back to the point, could you research what the cost would be for coating each one of your SS exhaust sections. I say each section because it sounds pretty expensive, so this might have to be done piece meal.

Bill

Bret,

I believe that Tim is again on the money here.

People have been polishing ports on normally aspirated cars for years to aid in flow (which helped your boat).

But you must remember that a turbo compresses the intake charge. When the charge is compressed it heats up! (thus intercoolers were born). Feel your air compressor cylinder after a cycle....On second thought don't feel the cylinder, OUCH!

When you start with a cool charge, keeping the charge cool makes sence. When you start with a hot charge, cooling the charge (thru heat soak via the aluminum) makes sence.

Ski

That is why I have an upgraded intercooler and will vent my nose panel, to help cool the charge even further. But I still say that if the it will keep heat in, in a hot section, it will keep heat out running in a cool section. Anyway, it should be finished next week, along with a spare section of down pipe.

Luke

So I shouldn't have my intake man. anodised?
How much of a difference(negative) could anodising make?

TurboTim

Aluminum dissipates heat. Nobody will disagree with that:^) If you put some kind of insulation, coatings, etc.... you will not dissipate as much heat. You will keep the heat in. You definitely do not want this on the intake side of any car. Aluminum will still get hot with Jet-hot coatings and when it does, it will not diispate the heat as well. The heat will remain there for longer. This would not be a bad thing if we were talking about anything below ambient air temp in which it never really got heated up. However, the fact is that the engine remains hot most of the time and so will the charge air. Now to be honest, will coating the intake with Jet-hot really have any negligable effects on the thing we are most concerned for and that is, Power? Probably not. I was just pointing out that it should be avoided if possible;^)


Tim
86 951 http://www.speedforceracing.com

Irish

OK, I could be wrong here but my take on this is as follows: The coatings and/or heat wrap helps by keeping the heat inside the exhaust manifold or header to improve scavenging. I have used these with positive results on racing engines. Heat is horsepower. You want to keep it in the pipe and out of the engine bay. With turbos, once the hot gases go thru the turbo, you want to expel them rapidly to reduce back pressure. From the outlet of the turbo toward the rear, I would think that anything that hold heat in would actually hurt your performance by increasing pressue. That is why many hi-perf racing turbos have almost no exhaust pipe just a short big tube to eliminate back pressure. Keep in mind that once you have enough boost to cause the wastegate to open, you are wasting any additional heat in the exhaust anyway.

With coatings or wraps what you will notice most is less turbo lag better response.

Danno

Well, after the turbo you want to keep the gases hot as well. This keeps velocity up and pressure down (slow velocity = high pressure). If the air-column cools down halfway through, it'll slow down and bunch up, causing pressure build-up behind it. Just imagine a line of people getting into a movie theatre. All it takes is a couple of folks in the front to slow down and everyone else has to wait.

belz

Hey Tim (anybody)-
I like the idea of coating the stainless. Question for you?: Will the coating "plug-up" the resonated tip?
Does anyone know if you could specify to whomever is doing the coating that the inside portion of the resonated tip should not be coated? ... I'm not familiar with the coating process.