here are my thoughts...

people used to wrap their headers to keep heat inside the tubes to keep exhaust gas velocity at a maximum (please correct me if i'm wrong)

over the past decade, ceramic coating seem to have replaced wrap as the insulation of choice.

now, most everybody i know just coats the outside (95% probably do it because its pretty-pretty) and leaves the inside as is. In my mind, this could be less than optimum. With this arragement, heat can still "soak" into the metal of the header BEFORE reaching the ceramic coating/insulation. If the coating were sprayed on the INSIDE of the headers, the heat would encounter the ceramic coating/insulation FIRST and possibly more heat would be retained in the exhaust gasses therefore maintaining a higher velocity.

would this be possible?
will these coatings survive the temperatures at the exhaust port mouths?
if the exhaust gasses remain hotter will this equate to a higher velocity and therefore a power gain (or less of a loss at least).

in specific, i am dealing with a blower car with roughly 32-35lbs of boost, roughly 1000rwhp. the headers are being made out of stainless steel by kooks. i am just trying to "find" any power we might be leaving on the table. even 15 - 20hp is a big deal in the class we run in.

thanks for your thoughts....

joe

 

Huh? My local shop always coated the insides with a misting wand.

Mark

 

nobody around here tha i know of bothers to coat the insides that i know of...

so, apparently there is probably some advantage to doing it that way...

anybody else???

joe

 

I had a set of headers done by Jet-Hot about 10 yrs ago and at the time,if the headers were brand new,never run,they coated inside & out and guaranteed them for life.

 

ok.. let me rephrase and see if i can get any more input...

i know that people DO coat the inside of headers as well as the outside.

is the coating inside done to boost performance or inhibit corrosion??

if had only enough $$$ to coat EITHER the inside or outside of your headers, which would you do, and why?

ps. i dont give a rats ass about the asthetics at this point, especially because the tubes are likely going to be polished stainless.

joe

 

I'm sure that coating the inside of the headers, to keep the heat inside the tubing (instead of letting it soak into the metal and radiate out), will help. How much, though? It's probably minimal. One of those diminishing returns things.

Personally, I ceramic coat the crap out of anything hot just to prevent corrosion. You're not going to get an astronomical horsepower gain with the coating, and it's probably easier just to throw another pound of boost at the engine to make a bigger power gain. If I was Michael Shumacher, then I'd worry about it.

If you go through the pits at a big race and look at the faster cars (the World Street Nationals is only a 15-minute drive from my house every October...plenty of fast stuff there), you'll see that there's a lot less rocket science than you would think. Some things make a difference, but plenty of them don't.

Mark

 

Corrosion protection is number one.
Thermal is number two.
Wrap will provide more thermal protection than coating.

Although, from painted steel to coated.
Coated made a hugh difference in underhood temps and melted wire and looms.

 

Waste of money to coat SS headers,but that's just my opinion.

is the coating inside done to boost performance or inhibit corrosion?? BOTH

 

problem with the class (NMRA EFI Renegade) is that the rules are so damn restrictive and there are several teams (the one i am part of being one of them) that have been around since the inception of the class. what it comes down to is the same basic combos have been used for years and stretched a little further every season. we're to the point where the small modest gains are needed to get the edge. plenty of our races are decided by hundreths and even thousandths of a second.

until the rules are openned up, i think that there are going to be no more substantial gains in power in these set-ups. its going to be tweaking little aspects and pooling together a number of modest power gains to make a difference.

if coating the headers is worth 2% and coating the intake and discharge tubing is worth another 1% and coating the pistons skirts is retains 1%, by god i'll take it (i just threw those % out there to illustrate a point) and consider it money well spent.

if it were only as easy as pulley'in down for another few psi... we already make enough boost to peg a 3 bar map and spin that YSi well past its recommended limits. if it were physically possible to make any more boost, the belts would disintigrate before we hit 1000' (gotta run an 8 rib).

back to the topic, i actually had a few minutes at work today to make a few calls and i was told several times that there is no way to consistantly coat the inside of a long tube header's primary tubes (and be able to guarantee good adhesion). i can see how it could be difficult to media blast the inside of the primaries, something i didn't even think of initially.

what seemed the most promising was a Swain coating that is supposed to go on about .015" thick and high an extrememly high ceramic content.

thanks for the input guys.. i'll welcome any more that comes my way.

joe

 

Also, practicing to be able to cut the shit out of a .400 tree is the best way to get 1320 feet away before the other guy, and it's practically free.

There's a reason why I'll never build a car specifically for a class. My buddy just about went broke building and racing a Real Street car. 75% of the way through building the car, he said that he "could have had a new Viper by now."

Mark

 

brian been running this class since before it even officially existed... he wont admit it, but its like a crack habit for him. i think it would physically pain him to quit running in Renegade.

one thing i'll say for brian, he can kill a .400 pro tree. in elimination .407 - .415s (.07 - .15 rxn time) are the norm. of course his wizard car's chassis is getting tired and the 60's have slipped to 1.30 - 1.35s

but demon race cars down in florida just finished up a new edge 25.5 for him that should debut no later than 3rd race... we're hoping for consistant 1.25 - 1.28 60's. (those king of 60's should put us consistantly in the 8.5x range)

the biggest problem right now is thinking far, far outside the box to try to find power that isnt so obvious that all the other teams have found it...

joe

 

Let's hope we don't find some magic power in this thread while the "other guys" are reading...lol

Mark

 

i did come up with one idea i am quite proud of last night... just pending approval by the guys who write the rules...

didnt you sign that privacy/non-collusion statement on your way in?!?

joe