Got a huge bonus coming up and I am thinking of welding up my own header.

I have done lots of research on header design in regards to any engine and I have come up with a "in my head" design plan for my car.

I was thinking that an unequal primary length header, with shorties would be the best option for me. I figure the shorty header would be better for me than the RB header since the RB header sounds like a pissed off bee hive. As for the unequal primaries, I was thinking about doing a shorter primary from the rear rotor and a longer one from the front.

I know I am going to have to do a lot of math designing this, but I really want to take on this project as I see it will be fun. Any tips, holes in my logic are appreciated.

 

I was just wondering what source you researched in order to come up with the idea of unequal primaries on a rotary engine.

 

I would consider buying a header if you have more money. I'm also curious why you would want an unequal length header

 

I totally understand where you are coming from, and everything I have read says that it is not useful. However, I read a thread on here very recently where a guy had fabbed up an unequal length header for sound purposes. I'll try and find his build thread and post a link.

 

Subaru rotary! you might want to make the 2nd rotor really short and make rotor one really long, double length or so. lol

 

here is my plan when i get off my a$$. there are a few ways to skin the cat, and mine is the simplest, and least expensive. the simplest and most expensive is to contact defined autoworks and they will build you a dyno proven exhaust from stainless that is also quiet.

RB sells an unassembled header. this gives you the flanges and already bent pieces of pipe. the pipes appear to be slightly longer, so this lets you fix the two problems in the FC header. the first is that the outlet of the engine is 48mm and the header is 43mm, so you need to port/swage the inlet of the header larger. the second is that the bend on the front header pipe is right as it comes out of the engine, and its been proven that you want a straight section right out of the engine.

part 2, is that since i do not know what length header my engine will want, i want to try several. RB sells the 2" thickwall pipe in 4' sections, you can buy elsewhere, but RB's price is actually good. i want three of these, cut one in half and then you can test primary lengths from 90" to about 26" i was going to buy some of these JEGS Performance Products 30850 JEGS Stainless Steel Lap Band Exhaust Clamps - Free Shipping on All Orders @ JEGS and then i can just bolt it together on the dyno and see what the engine wants.

if you wanted to run a cat, or a center muffler, you don't need all this pipe, as you'd just be trying header lengths in the 19.6"-32" range.

in a street car i'd run 2.5" pipe, if you want dual exhaust, then into 2x2" pipe, into whatever muffler you want.

 

j9fd3s, good info, thank you.

I did find the thread but couldn't pinpoint where he changed the header to unequal, as it's long and buried in there.

https://www.rx7club.com/build-thread...rt-fc-1015644/

 

does that car even run?

 

No.

 

Details, details.