DIY Exhaust Manifold
 

Do you guys see a problem in buying a flange and some piping from Racingbeat and building your own manifold?

http://racingbeat.com/photos/16189.jpg

http://racingbeat.com/photos/16181.jpg

My friend build is making his from a used 13b header

https://www.rx7club.com/attachment.p...d=112214&stc=1

https://www.rx7club.com/attachment.p...d=112215&stc=1

so whats the difference between that and this?

https://www.rx7club.com/attachment.p...d=112217&stc=1

I guess my questions are: Why are some people charging $600-900 for something that the materials seem to be somewhat inexpensive?

Will a header from a NA/13B withstand the temps of the turbochaged Rotary?

looks pretty good to me, only diff i see is external wastegate,but im sure one could be easily incorperated into it. I dont see why it coudnt stand the heat

That 600 dollar difference is for TIG welds, an external wastegate (necessary), stainless construction, and no HUGE KINK in rear runner =)

I only paided 200 for my exhast manifold for my twin kit. 341 SS 2.5in u-bend. had a local exhast shop do the tig welding for me...works great.


that bend in the rear turbo runner is going to hurt the flow somewhat.

I know the wastegate cost alot. The one in that pic is $600 alone.

http://www.youngsperformance.com/art...84255638/print

I guess I'll let my friend know he might want to fix that spot on his manifold.

Thanks for the info.

Get the disassembled header http://www.racingbeat.com/FRmazda1.htm it's $88.00 and the piping is mild steel and .125 wall thickness it won't crack. You'll have more than enough piping to make any manifold you want. All you'll need is the flange for the turbo and flange for the the wastegate. Also what are your horsepower goals? Depending on what kind of boost your making you can go with a different wastegate than that Newgen. I picked up a Tial 46mm for under $500 from here http://kgparts.com/tial_wastegates.htm

I've destroyed .125 thick mild steel headers in two years of racing with an N/A car. The heat from a turbo car is even greater. My advise would be to go very thick with mild steel or go stainless. You also want to keep the runner length equal and have the manifold as straight as possible. you also want flat flanges which often warp from welding processes other than TIG.
In short, a really good exhaust manifold is the result of a careful design, excellent fabrication skills and a strong understanding of the requirements for the system. I've seen some very well thought out and well crafted manifolds on here. That thought and effort will equal performance and longevity.

-Trent