Turbo header design

[Jon Fedock]

This thread greatly interests me because (to me) there is no better sound
than a NASCAR car at Talledega/Daytona/etc. where 180 degree headers are
used. I thought I almost understood what the term "180 degree headers"
meant, but evidently I am missing something. Questions posted below in
quoted posts:

-----Original Message-----
From: Gary Derian <gderian at cybergate.net>
To: diy_efi at efi332.eng.ohio-state.edu <diy_efi at efi332.eng.ohio-state.edu>
Date: Thursday, January 07, 1999 8:14 AM
Subject: Re: Turbo header design


>A reasonably close approximation to true 180 deg. headers can be made with
>the old tri-Y approach.  As Aaron wrote, true 180 would require merging
1-6,
>8-5, 4-7, 3-2 which is difficult to make.  Merging 1-5, 3-7, 4-6, 2-8
>enables cylinder pairs to share an exhaust pipe without interfering and is
>relatively easy to build.  This is common in high output European and
>Japanese V-8 engines.

Do they have 4 exhausts exit the car? Or are there collectors further
downstream to make it duals or a single?

> Ferrari, on the other hand, uses a flat crank to make
>a true 180 header easy.  Formula 1 and CART V-8 engines also use flat
>cranks.


This I understand (WoooHooo!).

>Flat crank V-8's vibrate like 2 4cyl engines.  A 90 degree crank V-8 has
>complete primary and secondary balance with only weights on the crank.


    Care to elaborate on this a little? Are we talking about crank vibration
(hamonic balancer/flywheel) or something else over my head? Also, a Chevy
V-8 fires every 90 degrees of crank rotation. How does a flat crank V-8
fire? Every 180 degrees would make sense, but then it would take 4 turns of
the crank to hit all 8?! I am so confused......

>Gary Derian <gderian at cybergate.net>
>
Thanks for any input.
Jon Fedock