grantmac

I was recently reading the section of Paul Yaw's site that talks about headers. Specifically it mentions that the header shouldn't bend until 3" after the port face, which means the RB header turns too quickly. It then showed a header made up out of what appeared to be weld "ells" which I know is pretty common for a turbo headers; but I've never seen it used for NA application. I was just wondering because this seems like it might be a great way to get a smooth flowing equal length header without having access to a mandrel bender. The only issue I can see is with weight.
Grant

grantmac

I guess I didn't really pose my question well, it is:
Has anyone used weld els and can they comment upon how well the result would flow versus the weight issue.
Grant

jgrewe

iTrader: (1)

Because of the heat generated by a rotory you can't get very long life out of thin walled tubing. So no matter how you bend it or weld it together its going to be heavy. Have you weighed a RB header? I'm pretty sure its .125" wall tubing.

grantmac

My RB header is thick, I'm thinking the weld els could be a nice low-cost upgrade from the RB unit. However I'm also thinking my stockport 13B might not notice the difference!
Grant

jgrewe

iTrader: (1)

Does RB still sell the header 'kit'? I've had good luck with the parts they sold making my own. You could just find a supplier of U bends and start cutting and tacking, the fact that they need to be thick to survive makes it easy to weld.

Just checked the RB website, you can buy U bends(3" and 4" radius) , flanges, collectors all pretty cheap. Thats probably where I'll start when I make new one.

Rx7carl

Yaw probably did it that way because it was a prototype/development piece. If you want to brew your own Id suggest using a quality SS. The RB design is definately far from optimal. Its a cookie cutter, one size fits all so there definately room for improvement. And Mr Yaw's statement about the RB header turning too soon is correct.

rotarygod

iTrader: (1)

Paul Yaw doesn't use weld els. He uses stainless tubing. He just cuts it and welds it very nicely.

88IntegraLS

I'd like to build a header that is tuned to the second resonance at 6500 rpm, so it will be tuned for the first resonance at 3250 rpm for a little midrange boost. Concept being like a long collected system tuned to the fourth resonance, only not as long without as many resonances.

PDF

Like this

grantmac

Yeah like that, could be a decent low-bucks alternative. The only thing I wonder is if they make plumbing collectors that would work for the back or if I'd just fab it. That looks like a very nice flowing header!
Grant

RX744CSP

iTrader: (4)

Not being the world's greatest fabricator, rather than make my own flanges etc I bought a RB kit to build the header for my 12A powered Spitfire. It comes with enough stuff to make just about anything you can think of, the tubing is 2" .120 mild steel, which is heavy but strong and easy to weld. I had to fabricate a 2 into 1 collector, I had enough tubing left to make this.

doridori-rx7

iTrader: (3)

El's are great but you need to ID match them pipe and tube have different system of measuring a 2.5" EL is really only ~ 2.125 ID in sched 10. welding El's is easy for a mildy experienced TIG user. However I've built street ported NA headers out of 304L .065" wall without ANY degradation to the material, even with heat wrap on it. weld El's are great for turbo headers and I'd stick to using it for that.. it's a bit of over kill for an NA unless your going to be living in the top end for very extended periods of time.. then I'd look into .083" wall 304L with flange gussets, a SS flex pipe section and firewall hanger before the cat- after the flex pipe.

grantmac

I think I'm just going to chase my tail until I get around to sorting out the header-back section of my exhaust and a better intake. I've currently got a rather restrictive Y-pipe after a RB road-race header. I'm going to shorten the primaries to fit another muffler and do a much more gradual collector because I'm sure I'm loosing power there. Also I'm going to have to do something to improve the S4 lower intake manifold, it's a mess. I might just start from scratch with something like a Lakecities manifold straight out to a set of 46mm throttlebodies I have. Standalone is already installed so tuning isn't an issue.
Grant

P.S. I'm also intrigued by the thread about negative split, could make for some interesting experiments on an NA.