like i said, i'm building my own here, i picked up some 12 mandrell stainless elbows and about 20 feet of piping, and allready have the 1/2 flange made and along with about 2 pipes made, i have the design all calculated etc... equal lenght.

just that i can't locate any other size than 1.5 and 2.0 for mandrel elbows, nobody else can get them, altought other size piping is available, so i basically made a 3 inch cone that goes from an oval shape (perfect size of the exaust ports) to the 2" outside dimensions of the piping, then i tigged everything up,

it's a 4 into 1 design, with plenty of ground clearance, and should perform great.

wondering on suggestions, many people have stepped headers, and some have 1 3/4 for primaries then fall to 2" ... well i coudln't get 4 elbows for the first 4 bends exiting the flanges so i decided to make it this way....

i'm curious on what the results should yeild, compared to a stock peice ?

lower torque gains but more hp, or otherwise or ?

.....

anyways just thought i'd give you guys some info... on comming projects since i'm finished my Euro-R manifold, (all tiged and stuff)

 

My opinion is that it will work great... way, way, up high, probably higher than 99% of "performance" engine run, 10-12Krpm or so?

Compare this size to what a 427c.i. race engine uses... about the same.

Also remember it's the cross-sectional area that's important, not the diameter. Sizes of 1.5" and 2" are night and day different. The ratio of area is 4 / 2.25 = 1.77. Think about that jump in size... what other part in your car would you try changing by that much...

I think it would be best to do lots of research before spending a lot of time building something that probably won't work as you need.

 

the piping is called "tubing" and is 2" perfectly outside diameters so 1.866 inside.

i looked at the SMSP headers, hitech, etc etc and most of them are all in that area.

I don't think i'm off that much, i do have stage 3 cams, and a portflow head, with a good flowing intake so this header should perform good compared to a stock one, it only costed me 60$ for all the stuff so with about 18 hours in design and pre-assemble then another 2 hours to tig and ensure fitment...

I don't think for 60$ plus argon gas for the stainless tig it will loose power througout the powerband. my motor should make power in the mid-high 8000rpm or so. if not i'll add a shorter intake manifold.

just looking for header primary comparisons..

 

Good to check out the competition. If their's work, and they're the same size, okay then.

What length are your primaries?

"I don't think for 60$ plus argon gas for the stainless tig it will loose power througout the powerband."

The labor and cost have nothing to do with how it will perform. If instead you mean that it's little lost if it doesn't work, that's different.

I still think it'll *just* be starting to work at the upper extreme of your powerband, and I still feel the best way is to "maximize the area under the power curve," not look for one extreme hp spike at one end of the range.

How you going to test it? A/B comparison at the track? Dyno? Post results either way.

 

BTW, I'm about to build my own header, and for comparision purposes, I'm using 1.625 primaries which were chosen for me by a header design service. I trust these guys so I'm going to use the recommended size for my mostly stock H22.

So FWIW, our designs differ by nearly 50% in area. For this reason I think your tubing is too large unless you're running at 50% higher redline which would be over 11,000rpm. Factor in the higher flow you expect and maybe we can lower that to "only" 10,000rpm or so. Still too high in my opinion but I would like to hear how yours turn out.

I also forgot to ask what collector size you'll use. You realize you'll need to test those in 0.125" diameter increments to find the right one...

 

I reread your post, where you say you cannot locate other tubing size.

http://www.burnsstainless.com/

 

well i said primary's but really it's 1.86 (trying to remember exactly) inside diamter full tubing from start to finish.. meaning it's only one size going all the way to the collector. so not really primary's just one size.

all 4 are 36 inch ( and have 3-4 inchs to play with ) if i want to make them sorter.