Turbo header design

[Clarence Wood]

  The tri-Y approach sounds more like the article that I read.  In the article, there were collectors for each bank.  Damn!  I can't find the article!  It is here, under a pile of other treasures, somewhere.  Anyway, they talked about matching the cylinders on each bank to scavenge, put in short baffles that led into a cone shaped collector that narrowed into the exhaust pipe.  
  Now, I hate to share my ignorance with you all, but I have ran into a problem understanding what is probably the most basic operation of a V8 engine.  Here is what I did to determine what cylinders should be matched:

                Firing order         
          1  8  4  3  6  5  7  2
Stroke
  1.      P  C  I  E  P  C  I  E       (P=power,C=comp,I=intake,E=exht)
  2.      E  P  C  I  E  P  C  I
  3.      I  E  P  C  I  E  P  C
  4.      C  I  E  P  C  I  E  P

  Why is cylinder #6 at a power stroke while cylinder #1 is also at a power stroke?  I am trying to find out where each of the cylinders are, in their four stroke cycle, when cylinder #1 is at its Power stroke.  What am I doing wrong??  Where is cylinder #6, in its stroke cycle, when cylinder #1 is on the power stroke?

At 07:56 AM 1/7/99 -0500, you wrote:
>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.  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.
>
>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.
>
>Gary Derian <gderian at cybergate.net>
>
>-----Original Message-----
>From: Aaron Willis <darkmonahue at awwwsome.com>
>To: diy_efi at efi332.eng.ohio-state.edu <diy_efi at efi332.eng.ohio-state.edu>
>Date: Wednesday, January 06, 1999 6:29 PM
>Subject: Re: Turbo header design
>
>
>>
>>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        Obviously these are all on opposite banks, so the
>>pipes need to travel around the engine some distance to collect in a 180
>>degree fashion. I really don't know much about whether the benifits
>>would outweigh the extra bulk and length of the exhaust system, but I
>>suspect not.
>>   HOWEVER it must be said that this arrangement does offer a killer
>>sound in NA form!  A gentleman in town has a '53 (?) Studebaker with a
>>406 Chevy in it, using standard NASCAR 180-degree headers collected into
>>a single exhaust, and it will raise the hair on the back of your neck.
>>Almost sounds like an exotic foreign supercar (or a flat-crank V8, come
>>to think of it)
>>
>>HTH
>>
>>Aaron
>>
>>ICQ # 27386985
>
>