For NA cars, a lot of tuning discussion involves 4-2-1 or 4-1 exhaust manifolds.

Could the same be true of headers for the Subaru engine? Are all headers and up-pipes effectively 4-1 arrangements or are there some 4-2-1?

I'm thinking that the firing order may complicate matters but I know SFA/2 about exhaust manifold design.

Jeremy.

 

The headers on a turbo car do not have the same scavenging affect as on an NA equivalent, due the large restriction that the turbo represents. However, the various design's all have an impact on performance.

Richard

 

The discussions I have seen seem to discuss different manufacturers equal or unequal length headers and downpipes. Also, the internal diameter of the pipes....and whether to wrap/not wrap...

Having read another thread earlier today (why do scoobs sound lumpy), I suppose that it's not as simple as connecting 1 & 3 and 2 & 4 together as the firing order would probably lead to some pretty weird effects.

Now if 1&2 and 3&4 could be connected, then have a twin uppipe with a long collector leading to the turbo....


Jeremy.