Orion84GSL New 321 Stainless Headers
 

Thought I'd show these off to you guys.I'm building Chris' new exhaust system. Starting from the headers and going all the way back. The headers are constructed out of 1/16" thick 321 stainless for best heat retention and durability. Collector was constructed with a 20 degree converging angle. Collects down to 2" and then is megaphoned out to 3". He'll be using a racing beat presilencer and racing beat muffler. Already welded the flanges on there, and the dump pipe.

https://www.rx7club.com/attachment.p...5&d=1339425962

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beautiful sam!

You should make a titanium header and exhaust system for the first gens, that would be amazing.

Any power gain if 2.25 OD is used over 2.00 (1.75 ID)?

That would be out of budget for 99% of the people on here, and not to mention it actually isn't the best material for headers. Inconel is the best way to go.

The wall thickness on these header are .065", so they're actually 1.875" ID. I doubt that going that big will make much/any difference as you much bigger than the exhaust outlet on the engine. I haven't personally tried it though.

That is bigger than RB and probably lighter too. Keep us posted.

I know, but the heat produced from the engine you turn the headers into the sweet blue monster color in all the hot spots.
I hope you start producing headers that aren't coated or anything special (like the racing beat headers) , keep the price low yet have them be able to take a beating.

Sam, love your work.

The racing beat (non collected) header weighs about 17lb. These weight in at 10lb.

Can't wait to see/hear this! :)





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Wow they look really good man nice job

Thats not the response I expected out of you! I was expecting you to say something along of the lines of "When will mine be ready?" :P after you've bugged me so many times for doing you an exhaust :)

Hope your recovering well btw.

What's the point of necking down at the collector to 2", then bouncing it back out to 3"? Is that pseudo venturi going to add enough to be unwarrantable just collecting to 3"?

Looks great. But I do have a question about your material choice. You mention you are using .065 wall tubing. It has been my understanding that this thin of material will generate a very tinny sound up near the header as it won't contain the exhaust sound enough and will vibrate slightly under the extremely powerful exhaust pulses. I would be interested in knowing if this is the case or not as I went to great lengths to find a supplier for 1/8" wall mild steel tubing to repair the RB header that I got for my 79, which is tinny sound free.

Keeping the collector smaller helps maintain the exhaust gas velocity within the tubing. The venturi effect helps pull it out even quicker with that air velocity being that fast. If you slow it down too quickly, that becomes dense air that is harder to push out of the collector area which is the most crucial area.

You're correct in saying that is won't contain it as much as 1/8". This is the first one that I do for a rotary myself, but compared to my SDJ headers (which are .035" wall I believe), thats alot more absorption than that. Also you stainless steel being a harder metal, will always sound a bit more tinny than steel. Aluminized tubing would probably take out the best though. But as with anything, you sacrifice weight for performance (just in being lighter not a more effective header). Trying to find 1/8" thick 321 stainless mandrel bent, I think that'll be extremely hard to find, not to mention bend. Most of the ones out there are .049 i believe.

That looks great! Esp the collector/expansion "collar". I probably can't a afford it but how about real expansion chamber like the megaphone RB has and add a short taper back to 3" for the rest of the exhaust.

Playing around with the length of the cone, changes the power band. Generally speaking the longer the megaphone, the broader the increase in power. Packaging that isn't always the easiest though. For the megaphones to work at their best, they need to stay perfectly centered with the collector hole (so no bends in there) Trying to fit a 2 feet section under the car and a pre silencer is no easy feat for a street car.

Burns stainless steel has a wide array of megaphones and reverse cones and have a wealth of knowledge on exhaust.

Hopefully one of these days I'll have an engine dyno, and experiment all that I can with it as far as exhaust goes. And I'll be kind enough to share that information with everyone here.

That was actually my first thought Sam. But then I realized I'm in no shape to pursue even a two legged cat at the moment. Soon, though. Very soon. :)

I think we need to hook up for the Woodward Cruise in Detroit this year. I may be bringing two FBs this time. :)




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Finally finished up the rest of the exhaust, here's the whole exhaust system outside the car. The muffler is a 2.5" Racing beat, and the resonator is also racing beat but 3". The Rest of the exhaust is TIG welded out of 304 stainless steel.

https://www.rx7club.com/attachment.p...1&d=1339876611

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I hope there is a video soon hopefully comparing this exhaust with the full racing beat exhaust.

I'm sure there will be a video going up soon. Its all installed in the car right now, and its running. Just need the owner to re-raise the car. Wheels are rubbing on the fenders, and there's only 1" between the floor and the pre-silencer (there's less than a 1/4" between that and the floor right now, so its not like its because it was welded too low).

Few more pictures.

https://www.rx7club.com/attachment.p...1&d=1339886948

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video of it:

Might just be the audio quality but it's quieter than I expected. Deeper tone too which is perfect. Can't wait to drive it!

yeah that sounds really nice