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Location:
Hobart
Registered:
May 2004
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Tuning headers?
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Thu, 10 June 2004 14:37
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As I'm about to perform my 2JZGE into MA70 conversion, i am getting custom extractors made. Now, I've been told - amongst a bunch of gobl-di-goob - by my mechanic that the firing order is important when designing extractors for a naturally aspirated engine. How so?
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Location:
Lost in the K hole
Registered:
May 2002
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Re: Tuning headers?
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Thu, 10 June 2004 16:16
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oh, crap... theres a tin of worms...
seriously, header design discussion is an ENORMOUS topic and theres no simple answer. but yes, firing order is important with their design.
hmmmm, think ill just cut to the chase a recommend a basic workable header design for the 2jz:
6-2-1 collector design
cyls 1+2+3 in one group
cyls 4+5+6 in the other
primary tube internal dia of 1 5/8"
primary tube length of 25-28"
secondry tube internal dia of 2"
secondary tube length around 36-40"
final collector internal dia 2 1/2"
cheers
ed
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Location:
Kita-Ku, Sapporo, Japan
Registered:
January 2003
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Re: Tuning headers?
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Thu, 10 June 2004 16:38
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i highly recommend reading Philip Smiths
"scientific design of intake and exhaust systems" for anyone that is interested..
and for a rough guess at pipe lengths, there is a graph on Bill's page.
Ed, what about running 6-3-1? (just to complicate matters  )
Cya, Stewart
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Location:
Lost in the K hole
Registered:
May 2002
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Re: Tuning headers?
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Thu, 10 June 2004 16:43
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| oldcorollas wrote on Fri, 11 June 2004 02:38 |
i highly recommend reading Philip Smiths
"scientific design of intake and exhaust systems" for anyone that is interested..
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excellent book - i hve only had a chance to fleetingly glance at it thou 
stewy - got a copy?
as for 6-3-1? eughhhh
give me 6-1 anyday if i had the space (or the budget to spend my whole life at WOT 7500rpm)
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Location:
Kita-Ku, Sapporo, Japan
Registered:
January 2003
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Re: Tuning headers?
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Thu, 10 June 2004 16:59
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| ed_ma61 wrote on Fri, 11 June 2004 02:43 |
| oldcorollas wrote on Fri, 11 June 2004 02:38 |
i highly recommend reading Philip Smiths
"scientific design of intake and exhaust systems" for anyone that is interested..
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excellent book - i hve only had a chance to fleetingly glance at it thou
stewy - got a copy?
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nope, but there IS a copy in the basement of the UNSW library!!
WIFTT, i'll borrow and we can get you another look... i read the whole thing.. not so great for actual numbers, but awesome for understanding..
i do however have "the design and tuning of competition engines" by the same author... dragged it back from Chicago when i was there.....
CYa, Stewart
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Registered:
August 2002
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Re: Tuning headers?
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Tue, 22 June 2004 08:13
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firing order is 1-5-3-6-2-4.
I purchased a set of the most unbeliveable stainless extractors for a 2JZ that collected in that firing order as opposed to the 2 seperate groups.
I had to sell them to a JZA80 owner as i couldnt bring myself to butcher them past my steering rack
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I supported Toymods
Location:
I renounced punctuation
Registered:
May 2002
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Re: Tuning headers?
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Tue, 22 June 2004 08:27
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| oldcorollas wrote on Fri, 11 June 2004 02:59 |
WIFTT, i'll borrow and we can get you another look...
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If this book is borrowed, would someone mind photocopying the whole kit and kaboodle. I'll happily pay for all photocopying/postage etc.
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Registered:
August 2002
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I Supported Toymods
Location:
Sydney
Registered:
December 2002
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Re: Tuning headers?
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Tue, 22 June 2004 09:10
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What about six to three to one?
1-6 5-2 3-4 pairs and then dump those three to one???
Either way its going to get messy!
You need a special service tool for your tests dude!
I'm thinking six bits of equal length garden hose and try to arrange the pairs as listed above... It'll work... Trust me!
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Location:
Melb
Registered:
June 2004
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Re: Tuning headers?
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Wed, 23 June 2004 01:27
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Yes the firing order is important. The header design needs to minimise turbulent airflow through the collectors, the builder will design a set of extractors that will promote good lamina air flow. As mentioned, this is one area that you could spend the rest of your life researching....
Perhaps get a few different opinions from different people and see what they recommend, if you get a bit of consensus on what is best i would suggest they are on the right track.
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Location:
Sydney, OZ
Registered:
May 2002
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Re: Tuning headers?
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Wed, 23 June 2004 05:22
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nope, but there IS a copy in the basement of the UNSW library!!
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That will go missing now..... 
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