180 degree headers WAS:Re: Turbo header design

[Shannen Durphey]

diy_efi at efi332.eng.ohio-state.edu wrote:
> 
> <snipperoo>
> 
> >Clarence,
> >  This is easily done with an inline four having a 1-3-4-2 firing order,
> >as you just pair cyl's 1-4 and 2-3 together.  Commonly done in NA
> >headers and OEM manifolds too.  However, true 180 degree headers on a V8
> >typically take up a lot of space.
> >   The only firing order i am familiar with is for a GM engine, which is
> >1-8-4-3-6-5-7-2.  Picture the cyliders as two rows (which they are):
> >
> >     1     2        you can see that #1's 180 degree partner is #6, #8's
> >     3     4        is #5, #4's is #7 and #3's is #2.
> >     5     6
> >     7     8
> 
> #1 and #6 are 180 degrees apart on the distributor, not the crank. #1 and #4
> are 180 degrees apart on the crank. Aren't they? What cylinders are grouped
> together with NASCAR 180 degree headers?
> 
> Jon
> 
> <snip>
Suppose it would make things easier to include "cam" or "crank". #6
is  180 cam degrees from #1.  Means that #8 reaches TDC at 630 crank
degrees.

Anyone willing to answer some "flat" crank questions off list?
Shannen