Looking for the Math on headers
Thread Starter
Supporting Vendor
Joined: Jul 2010
Posts: 8,550
Likes: 903
From: Republic of Texas
Looking for the Math on headers
I understand the concept of how headers are superior to traditional cast iron manifolds, but i'm looking for the math behind them, particularly how primary length and diamater affect various parts of the torque curve.
Any reccomended reading?
in case you're wondering, I'm considering moving from my frankenstein setup to a LG/Borla setup.
Any reccomended reading?
in case you're wondering, I'm considering moving from my frankenstein setup to a LG/Borla setup.
Tech Contributor
Joined: Jan 2007
Posts: 19,472
Likes: 1,171
From: Dyer, IN
I understand the concept of how headers are superior to traditional cast iron manifolds, but i'm looking for the math behind them, particularly how primary length and diamater affect various parts of the torque curve.
Any reccomended reading?
in case you're wondering, I'm considering moving from my frankenstein setup to a LG/Borla setup.
Any reccomended reading?
in case you're wondering, I'm considering moving from my frankenstein setup to a LG/Borla setup.
http://www.superchevy.com/technical/...der/index.html
Race Director
Joined: Sep 2005
Posts: 11,060
Likes: 291
From: Pasco WA
Why the need for pseudo science, when you can just choose from one of the top brands that're constantly talked about here. Go with LG Pros, NOT Superpros, which are also sold at Wally World, or so I've heard. 
Those guys @ LG have been very good to me regarding service, as well as quality.
Those guys @ LG have been very good to me regarding service, as well as quality.
Thread Starter
Supporting Vendor
Joined: Jul 2010
Posts: 8,550
Likes: 903
From: Republic of Texas
No offense, but have you tried doing a google search. There are tons of articles about headers. Here's one of many...:
http://www.superchevy.com/technical/...der/index.html
http://www.superchevy.com/technical/...der/index.html
Pro
Joined: Nov 2002
Posts: 603
Likes: 20
From: Chicago area (Crook County) IL
I understand the concept of how headers are superior to traditional cast iron manifolds, but i'm looking for the math behind them, particularly how primary length and diamater affect various parts of the torque curve.
Any reccomended reading?
in case you're wondering, I'm considering moving from my frankenstein setup to a LG/Borla setup.
Any reccomended reading?
in case you're wondering, I'm considering moving from my frankenstein setup to a LG/Borla setup.
Last edited by Domin8r; Sep 7, 2010 at 12:05 AM.
Le Mans Master
Joined: May 2006
Posts: 5,987
Likes: 18
From: DuBois PA
St. Jude Donor '11-'12-'13-'14-'15
Generally primary lengths are governed by the application, longer primaries for low end and shorter (mid lengths) for high end power. To truely get a set of Headers for YOUR car as every engine is different and they need to be custom built with a specific application in mind and that just isn't feasable or cost effective on a street car...
I don't think harmonics play a large role or as large a role as pulse velocity and scavagening, except at the collector. Reversion at the heads is also a troublesome nuance but with most well designed systems that isn't an issue.
FYI Equal primary length isn't nearly as critical as people make it out to be. They can actually range as much as eight inches in difference without any detrement.
I think your ever curious mind is getting you in alot deeper then you to dig for a street car!
I don't think harmonics play a large role or as large a role as pulse velocity and scavagening, except at the collector. Reversion at the heads is also a troublesome nuance but with most well designed systems that isn't an issue.
FYI Equal primary length isn't nearly as critical as people make it out to be. They can actually range as much as eight inches in difference without any detrement.
I think your ever curious mind is getting you in alot deeper then you to dig for a street car!
Team Owner
Joined: Mar 1999
Posts: 22,025
Likes: 192
From: At the beach in little Rhody
Here is an article on Jack Burns and Tri-Y headers. Link
The LS1 really likes the Tri-Y arrangement (note that the cast manifold from GM that came stock was also a Tri-Y arrangement).
The LS1 really likes the Tri-Y arrangement (note that the cast manifold from GM that came stock was also a Tri-Y arrangement).
Thread Starter
Supporting Vendor
Joined: Jul 2010
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From: Republic of Texas
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Team Owner
Joined: Sep 2003
Posts: 43,084
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From: Raleigh / Rolesville NC
Think it may also depend on which 'sweet' spot you want? the low to mid range torque curve sweet spot, or the higher rpm HP curve sweet spot.
Exhaust harmonics are a closely guarded secret
Instructor
Joined: Feb 2010
Posts: 159
Likes: 9
From: Greenville NC
I understand the concept of how headers are superior to traditional cast iron manifolds, but i'm looking for the math behind them, particularly how primary length and diamater affect various parts of the torque curve.
Any reccomended reading?
in case you're wondering, I'm considering moving from my frankenstein setup to a LG/Borla setup.
Any reccomended reading?
in case you're wondering, I'm considering moving from my frankenstein setup to a LG/Borla setup.
Thread Starter
Supporting Vendor
Joined: Jul 2010
Posts: 8,550
Likes: 903
From: Republic of Texas
I'm looking to get the sweet spot as close to 2000rpm as possible. My SC picks up around 2500-3000RPM. Before my SC install, my SSAC headers picked up around 3500 rpm. Right now i have a lull between idle and 2500 rpm. I'm hoping LG headers will help take up the slack in the lower part of the powerband.
Team Owner
Joined: Sep 2003
Posts: 43,084
Likes: 33
From: Raleigh / Rolesville NC
LGs will fill that 2000 to 3500 void. Second choice would be ARH. both are very close.
IIRC the Longer primary's and move the x-pipe as far back as possible provides much more low end torque. for thet Get up and gone, SOTP acceleration .
IIRC the Longer primary's and move the x-pipe as far back as possible provides much more low end torque. for thet Get up and gone, SOTP acceleration .
Last edited by AU N EGL; Sep 7, 2010 at 09:54 AM.
Tech Contributor
Joined: Jan 2007
Posts: 19,472
Likes: 1,171
From: Dyer, IN
I'm looking to get the sweet spot as close to 2000rpm as possible. My SC picks up around 2500-3000RPM. Before my SC install, my SSAC headers picked up around 3500 rpm. Right now i have a lull between idle and 2500 rpm. I'm hoping LG headers will help take up the slack in the lower part of the powerband.
Team Owner
Joined: Mar 1999
Posts: 22,025
Likes: 192
From: At the beach in little Rhody
I'm looking to get the sweet spot as close to 2000rpm as possible. My SC picks up around 2500-3000RPM. Before my SC install, my SSAC headers picked up around 3500 rpm. Right now i have a lull between idle and 2500 rpm. I'm hoping LG headers will help take up the slack in the lower part of the powerband.