Tony

thats sounds like preignition to me? detonation is the rapid, EXPLOSIVE burn of the mixture..it can occur during the regular ignition event or before it.

either way im sure it helps. The heat can still be dissipated out of the head..exhaust ports etc. The S4 has a pent roof chamber, identical to the 959 actually and is very detonation resiliant in design to begin with.

Im basically having my 10:1 pistons machined to appx 8.7-9.0:1 CR by altering the slope of the dish. Where the maching occurs the "raw" aluminum will be exposed again. So im looking at either or both hard anodizing or the ceramic coating.

I have to get the "test" piston back first to see how the maching went and what my new dish volume is.

so far sevaral 928s at 11psi and 525RWHP on 10:1..pump gas ..no issues. needless to say we'd like the CR down and all the "anti'detonation" stuff working for us.

roadrunner

Tony,

What kind of hard anodizing are you going to use? I thought that stuff usually flakes off at about 500 degrees F, as seen on a frypan. I used to work in a metal plating plant and we routinely got parts in for the space shuttle and 737s, but they were alway low temp parts like fuel manifolds and landing struts...

Laust Pedersen

I use HPC (http://www.hpcoatings.com/motorsports.htm) and so far only their “low temp” coating (HiPerCoat, 1300F) on various applications.
So far my 944T headers and exhaust after the wastegate and down-pipe have been coated in- and outside and so have my valves and combustion chambers. The headers are at places beginning to get dull due to the marginal temperature limit of the coating.

For access reasons I wrapped the crossover pipe and shielded the turbine housing. I don’t like to work with the wrap since it sheds a lot of particles. It is probably best to wear a mask when working with it. Wrapping also get stiff and tears easily with age.

Here are some things that I have been told by HPC: The thickness of the low temp (HiPerCoat) coating typically is .001” - .002” while the thickness for the more expensive high temp coating is .012” - .015”. The high temp coating is good for 2500F, is only for “line of sight” applications and is claimed to give much better thermal shielding. The HiPerCoat can handle higher temperatures in an oxygen starved environment (inside coating).
I got a quote on $245 for the cross-over pipe (low temp coating inside and high temp outside).

On another application I had pistons thermally coated on the top and anti-friction coated on the skirts. Unfortunately I had to open the engine after only 2000 miles and found the coating on the skirt worn off. So I draw the conclusion that the friction coating (at least the one I used) is only for racing with frequent rebuilds. Another advantage of thermally coating the piston crown is less to no coking of the oil at the bottom of the piston and less strain on the cooling system.

I would recommend getting a small sample of the thermal coating to get a sense of its capability. I got one before my first coating job and exposed it to a torch, hammered on it in a vice and ended up being quite impressed by its properties.


“needless to say we'd like the CR down and all the "anti'detonation" stuff working for us.”
Tony, how about port water injection? I have great success with this at 25 psi boost.

Laust

superfuzz

You guys may want to check out Performance Coatings. I don't have any first hand experience with them but they seem to have a pretty good word of mouth reputation here in Washington and prices seem reasonable. I am going to have the headers on my motorcycle done by them this winter. The web address is:

www.performancecoatings.com/

Magown

Lindsey just finished my exhaust, they charged me $250 to ceramic coat my headers, crossover pipe, turbine housing, and down pipe.

TonyG

I will always use a wrap over a coating on external engine parts.

The wrap I'm talking about is NOT the typical individual runner wrapping. These make a mess after time, fall apart, and lock too much heat into each pipe which after time will weaken the metal, and cause cracking.

The wrapping I'm talking about is the Thermotec aluminized wrap. You wrap the entire assembly (ala entire header with a blanket, or the entire hot side of the turbo extending down to wrap blanket style both exhaust pipes in and out of the turbo).

The benefit is that you can remove it, and reinstall it. It does not make a mess. It does not come apart.

And I can tell you this... I have my turbo hot side and about 15" of cross over pipe AND turbo exhaust, all wrapped with one blanket style wrap.

You can literally put the car on the dyno, do 5 runs, and put your hand within 1/2" away from the blanket, and almost feel no warmth. It's truely amazing. But you will be burned if you touch it.

After driving my car in normal driving, I can pull over, open the hood and my intake manifold is actually cool to the touch (real cool... definitely noticable). Put my hand down by the turbo (And I can because I don't have the need to have the heat sheild by the brake booster, and I have no turbo water pump) and there is zero heat given off.

Trust me... give the Thermotec aluminized blanket stuff a shot. It's awesome.

Oh... the trick to using it is to use regular scissors to cut it, but then fold the edge over about 1/2" and use a regular stapler to staple the fold over. Then you'll have a nice finished edge, with no possibility of material fraying. Looks real clean.

To fasten, simply wrap over say the header, trim appropriately to fit, then use some safety wire loops over the whole blanket. Not too tight. The aluminum forms around where you push it. Just barely loose. The safety wire is just there to keep it from slipping and moving. It doesn't take much to hold it in place.

When you have to service the car, cut the safety wire, and simply pull off the blanket. No mess, no residue, and it's totally reusable.

Good stuff...

TonyG

Ahmet

Where could one get this stuff, and how much?
Ahmet

TonyG

Ahmet

Summit Racing (www.summitracing.com) and I'm sure many other places as well.

Also, they make the Thermotec aluminized insulation in a "hose style". Which means that you can slide it over wiring... Great for preventing cooked wires.

TonyG

sm

TonyG,

Is this what you use?



And do you apply it with the fabric side towards the metal piping and the aluminum side facing away? Will the heat from the turbo burn the fabric side?

I have the car apart, so now's the time to use it.

EZRider

From a website which sells this stuff this is what they say...
"When used as a heat shield, the barrier is installed so the bright metallic surface faces the heat source. When used to retain heat in applications such as exhaust manifolds, the barrier is installed with the fabric side facing the heat. This allows the metallic surface to act as a barrier to prevent the penetration of liquids. "

scottz

Hey that just looks like a big roll of aluminum foil. Hmm, I have my headers off for a oil cooler seal replacement, maybe I'll have to steal my wifes aluminum foil out of the kitchen and wrap up those headers.

TonyG

sm

Yes that's the stuff.

It's awesome. They also make in a "tube" version so you can slide it over wiring/hoses,etc...


TonyG

Skip Wolfe

Hey Tony,

Any pictures of it installed?

Also, on a different subject, I saw on the pictures of your engine bay on your for sale site, a setup with clear hose that looks like it runs from some sort of control box to your intake manifold and your blow off valve. Just curious what it is.