Anybody Use Performance Welding Headers?

[Jeff Lee]

Back to the original question, stainless does offer a HP improvement. The pulses react differently to stainless than steel tubing. I can't say that from experience as I've never had the pleasure to own such a set. That's what my engine builder says. He also says some internal coatings (not ceramic based) are a good alternative. He DOES have the before / after to back up the stainless or coated headers vs. regular steel.
Maybe our engineer SSDiv6 can chime in...

[SSDiv6]

Originally Posted by Jeff Lee

Back to the original question, stainless does offer a HP improvement. The pulses react differently to stainless than steel tubing. I can't say that from experience as I've never had the pleasure to own such a set. That's what my engine builder says. He also says some internal coatings (not ceramic based) are a good alternative. He DOES have the before / after to back up the stainless or coated headers vs. regular steel.
Maybe our engineer SSDiv6 can chime in...

I will keep it simple because header design is a science that involves many parameters and the discussion can go for years due to the many theories and principles.

The use of stainless steel as header material does not have anything to do with exhaust pulses. The dampening of the exhaust pulse can be controlled with any steel if you vary its thickness or gage. In fact, the aircraft industry uses Inconel. The real factors are undisturbed exhaust gas mass and density, MACH/Supersonic exhaust speed and the heat transfer advantage the stainless steel material offers.

Because mild steel headers will deteriorate due to heat and corrosion, many racers will coat the headers internally to make them last longer. Do not get me wrong, keeping the heat inside the headers for a short time, is a good thing. However, when you coat the headers internally it has other effects such as reducing the exhaust velocity, and as a result, affecting heat transfer. Therefore, when you have a stainless steel header, you do not have the issue of reduced exhaust velocity and heat transfer because you do not have to coat the header internally.

Exhaust coatings have their place in applications of extreme heat such as turbocharged engines. In this type of application, a Ceramic coating is beneficial because too much heat can slow down the supersonic exhaust velocity downstream.

Again, it is an issue of much you want to spend. If you have a mild steel header and coated for longevity, you will give up some power. If you have the money, a well-designed stainless steel header will give you longevity and power. I said, “well designed” because I have noticed too many cars at the track with header designs that are either too big, too long or too short for their intent.

[Jim Wahl]

WOW! Lots of good info. Thank you sir! Jim

[Kenny Wigington]

Since no one else has, I have to ask the question, in all seriousness. How much HP are we talking about, material for material ? 1% to 5%, what is the real number, on 300 hp ? On 400, or 600 HP?

[SSDiv6]

Originally Posted by Kenny Wigington

Since no one else has, I have to ask the question, in all seriousness. How much HP are we talking about, material for material ? 1% to 5%, what is the real number, on 300 hp ? On 400, or 600 HP?

Material does not have the effect claimed. It is the design of the header that makes the power. Like I said in my previous post, if you coat the inside of the header, then you are compromising performance. If you have a stainless header, then you do not have to coat the inside.

[Jeff Lee]

Eric Bell, who has a "reasonably fast" 440-6 SS/E & FA Challenger, went from the header builder I have always used to Performance Welding. As I recall, in back-to-back dyno testing the PW headers were worth 15+ HP.
His style in building headers (from what I have seen) is exactly what I think is a prerequisite over "tuned length" headers, that is, Mark wants long stubs off the exhaust port and "swoopy" curves more so than being +/- 1/4".

[Alan Roehrich]

About 3-4 years ago, we did some dyno testing for NitroPlate. On a standard set of roadster style dyno headers, a 406 small block Chevy making about 500HP gained approximately 2% HP when we coated the headers. It took tuning to get there.

The first thing we found was that the coating leaned the engine out considerably, the average EGT increased by well over 120 degrees. We had tuned the engine to around 13.2:1 AFR, which yielded the most power before we coated the headers.

With no other changes but the coating, the AFR went to around 14:1, and the EGT went to 1480 + degrees at the end of a 20 second pull. That first pull was down about 4%-6%. However, after we got the AFR back to 13.2:1, and the EGT back down to 1360 or so, we had gained a little over 2% over the base line.

If you tune and record EGT, you may find that you cannot get the EGT back down to where it was before the headers were coated. The coating reflects heat back into the header, so even properly tuned, the EGT is often higher than it is with an uncoated header.

We did not do any testing to see if there were gains to be had because of a reduction in under hood heat. We hope to do more testing in the future, but we haven't scheduled anything as of yet. We did test intake coating, we found around 1% or so on a dual plane single 4 barrel intake coating the exterior only, top and bottom, on a 350 small block Chevy 350HP limited circle track engine.

[340Cuda]

Originally Posted by Kenny Wigington

Since no one else has, I have to ask the question, in all seriousness. How much HP are we talking about, material for material ? 1% to 5%, what is the real number, on 300 hp ? On 400, or 600 HP?

Jere Stahl told me once that headers had about 5% to do with total drag car performance. If he is correct, I would think header material would be some fraction of that.

This is a good thread!

Bill

[GTX JOHN]

Jim: We are going to see if we can find Mark at Sportsnls. next week....we need 3 sets ourselves....maybe if he builds a bunch at once we can get a little bit of a deal. I have a couple of step design we have been using that work well. Racer7411@yahoo.com

John Irving

[Adger Smith]

Does he have E-mail or web site?