Got My OBX Headers Today

[XfireZ51]

Retaining heat in the exhaust slows energy loss. The
more energy on the exhaust the faster it moves out.
Thus helps with scavenging the cylinder drawing spent gasses out and helping to fill cylinder with intake charge faster. At top end this becomes more important because there is very little time for valves to be open.

[tomtom72]

Originally Posted by Corbusa

I have a few questions.. Are all ZR headers stainless? ( i would prefer Stainless but when the times comes it will depend on budget ) , can they coat regular steel headers? I had a pair of Headman that were over 15 yrs. old and are still on the truck I sold a few years ago.. They were plain old cheapies. When they were hot I would rub the old motor oil on them , to help prevent rust .. It must work...
I'm no Einstein , So I'm asking .But since the heat is trapped inside the coated headers wouldnt that raise the cylinder temps.? I mean if its coated and the ambeint temp.is lower , then isnt the temps. inside the headers higher? I understand what some of you are saying about cooler air outside , would help lower the temps. inside. I'm just trying to see it from both angles.. So please learn me

The simple answer is no. The more involved answer is: if the gas stream looses heat it slows down. Then it backs up the flow due to loss of speed. Then that back up keeps the heat closer to the cylinder head creating a "blockage" area that backs up the intake flow and heats the incoming charge. The swaintech guys can coat any metal, and all s/s is not the same there are different alloys. I think maybe Carter could speak to that question. My only experience is with s/s in the marine environment. There it does matter what grade you use. Only thing that I know for sure ( not from any hands on time ) is that generally the higher the grade s/s the more careful the welding has to be from controlling the welding environment aspect, and the harder it is to dress the welds after.

Tom

[Shrek]

Brett, I ordered a set online last night. What gaskets come with them? Or should I order a set from Jerry's?

Jeff

[secondchance]

Originally Posted by Shrek

Brett, I ordered a set online last night. What gaskets come with them? Or should I order a set from Jerry's?

Jeff

I would order a set from Jerry. Gaskets that came w/ the OBX are indiviual gasket per exhaust port - 8 small gaskets. These would be a major pain to use.

[Blue Flame Restorations]

Originally Posted by secondchance

I would order a set from Jerry. Gaskets that came w/ the OBX are indiviual gasket per exhaust port - 8 small gaskets. These would be a major pain to use.

Yep, the small ones were in the box. I'll be ordering from Jerry as well.

[Shrek]

Originally Posted by secondchance

I would order a set from Jerry. Gaskets that came w/ the OBX are indiviual gasket per exhaust port - 8 small gaskets. These would be a major pain to use.

Originally Posted by Blue Flame Restorations

Yep, the small ones were in the box. I'll be ordering from Jerry as well.

THANKS GUYS!!!

Just wanted make sure. Now I can add them to the list of gaskets I'm ordering for the injector housing/plenum pull. Getting ready to pull the plenum again and yank out the secondary stuff.

[efnfast]

Thanks guys, you're answering all my questions about which headers to buy.

[Aurora40]

I am in no way an expert... But exhaust slows down as it cools because it doesn't need to flow as fast. As it cools, the volume the gas takes up is reduced, so it can move slower and still move the same mass per unit time.

I'd tend to think the more heat you could shed in the pipes, the less of a restriction any fixed-size piping becomes. And I'd think the frictional resistance to flow would be less at lower speeds.

I thought the main reason for coating headers is that they are generally much closer to wires and other things under the hood, and you don't want to fry/burn those things.

[XfireZ51]

The ceramic coating also helps in the functioning of the O2 sensor. In most cases, locating the sensor in the collector typically is further from the exhaust port than stock. Even tho the O2 is heated, keeping the exhaust hot longer and further downstream also helps with the accuracy of the sensor.
Keeping up velocity of exhaust gases helps with the scavenging effect providing a slight "turbo" effect to the intake charge.

[Paul Workman]

Originally Posted by XfireZ51

Keeping up velocity of exhaust gases helps with the scavenging effect providing a slight "turbo" effect to the intake charge.

Bob is right...

And, is exhaust scavenging an issue with the (4-valve head) LT5 in particular?

If someone believes that ceramic coating will improve performance (in our application), sans anything resembling actual data, I know where you can also buy a couple of those "Tornado" thingies to install in your air horn for a "big boost in hp and fuel economy!"



Aside from some other benefits e.g., less radiated heat, etc, I ain't buyin the notion that the coating has done anything to improve performance of the LT5, until proven otherwise.

As for appearance & less radiated heat to flooring and wires in close proximity...go for it. As for performance benefit, I'm not from Missouri, buy ya gonna have to show me!

I'm just sayin...

P.