Length of header primaries

joespanova · 01-28-2021, 07:58 PM

How much can they vary within the same set without some negative effect on power? 2 inches , 4???

Adger Smith · 01-29-2021, 11:20 AM

http://speedtalk.com/forum/viewtopic...42375&start=15

http://www.exhausting101.com/?p=37
http://www.speedtalk.com/forum/viewtopic.php?t=41836

Check these out & look into Calvin Elston.
He blows away some myths about Exhaust systems.

Alan Roehrich · 01-29-2021, 12:39 PM

Larry Meaux, the guy who does PipeMax software, is another good source.

joespanova · 01-29-2021, 01:14 PM

Thanks guys...Adger , lots of intense reading there...LOL
Alan I have a copy of PipeMax also...I'll take another look. When he gives you a "range" of lengths that fit the harmonic order , then I can only assume that as long as you're in that range , even if there's length variation....you're good to fly.

Wayne Kerr · 01-29-2021, 01:27 PM

Some guys even run unequal length on purpose.....

See you at the races,
Wayne Kerr

Adger Smith · 01-29-2021, 07:43 PM

Joe,
You are correct about the reading... & I am like you on the range of pipe length. I would say hit in there some where in his range. That is exactly how I had my headers built for my V-6 in a Gen 3. Even the steps vary some. They seem to work well. After all the header is just Rocking the TQ Curve up or down...
2 " on a 32" pipe is about 6%.. off the top of my head..

joespanova · 01-29-2021, 08:36 PM

Quote:

Originally Posted by Adger Smith

Joe,
You are correct about the reading... & I am like you on the range of pipe length. I would say hit in there some where in his range. That is exactly how I had my headers built for my V-6 in a Gen 3. Even the steps vary some. They seem to work well. After all the header is just Rocking the TQ Curve up or down...
2 " on a 32" pipe is about 6%.. off the top of my head..

I talked to Calvin for about 30 minutes today......great guy , really knows his header design....fun talking with him. He asked me how I found him...I dropped your name , he knew / knows of , you.
In summary , he suggest more emphasis on the collector ( make that a merge) as a way of influencing the relationship between a primary too short or too large and its connection to recovering torque (in the event of too large a primary )...or , a smaller collector.

gmonde · 01-31-2021, 04:00 PM

i have built a few sets of headers for street cars,stockers and chassis cars ,, in a stocker engine bay is very challenging to map out your equal lengths, but being careful not to create restrictions by trying achieve equal lengths ,i always try to plot out the smoothest paths with out to many bends and using bigger radius bends where i can , collector sizes are like camshaft choices, you can get close but to find that perfect combo dyno testing is key to getting the most out of the combo, but as you know there just isn't enough time to test everything
in my opinion you want to focus on what you can build for torque ,,most carbureted stocker engines are done making power between 6200-6700 ,, torque around 4500 -5000,,,

gmonde

01-28-2021, 07:58 PM	#1
joespanova Senior Member Join Date: Jun 2011 Location: Ga. Posts: 521 Likes: 7 Liked 13 Times in 11 Posts	Length of header primaries How much can they vary within the same set without some negative effect on power? 2 inches , 4??? Last edited by joespanova; 01-29-2021 at 06:59 AM.

01-29-2021, 11:20 AM	#2
Adger Smith VIP Member Join Date: Dec 2001 Location: Texarkana Ark/TX Posts: 2,446 Likes: 575 Liked 880 Times in 311 Posts	Re: Length of header primaries http://speedtalk.com/forum/viewtopic...42375&start=15 http://www.exhausting101.com/?p=37 http://www.speedtalk.com/forum/viewtopic.php?t=41836 Check these out & look into Calvin Elston. He blows away some myths about Exhaust systems. __________________ Adger Smith (Former SS)

01-29-2021, 12:39 PM	#3
Alan Roehrich Veteran Member Join Date: May 2006 Location: Murfreesboro TN Posts: 5,090 Likes: 1,534 Liked 1,758 Times in 398 Posts	Re: Length of header primaries Larry Meaux, the guy who does PipeMax software, is another good source. __________________ Alan Roehrich 212A G/S

01-29-2021, 01:14 PM	#4
joespanova Senior Member Join Date: Jun 2011 Location: Ga. Posts: 521 Likes: 7 Liked 13 Times in 11 Posts	Re: Length of header primaries Thanks guys...Adger , lots of intense reading there...LOL Alan I have a copy of PipeMax also...I'll take another look. When he gives you a "range" of lengths that fit the harmonic order , then I can only assume that as long as you're in that range , even if there's length variation....you're good to fly.

01-29-2021, 01:27 PM	#5
Wayne Kerr Member Join Date: Nov 2003 Location: Out to Lunch Posts: 191 Likes: 2 Liked 26 Times in 11 Posts	Re: Length of header primaries Some guys even run unequal length on purpose..... See you at the races, Wayne Kerr

01-29-2021, 07:43 PM	#6
Adger Smith VIP Member Join Date: Dec 2001 Location: Texarkana Ark/TX Posts: 2,446 Likes: 575 Liked 880 Times in 311 Posts	Re: Length of header primaries Joe, You are correct about the reading... & I am like you on the range of pipe length. I would say hit in there some where in his range. That is exactly how I had my headers built for my V-6 in a Gen 3. Even the steps vary some. They seem to work well. After all the header is just Rocking the TQ Curve up or down... 2 " on a 32" pipe is about 6%.. off the top of my head.. __________________ Adger Smith (Former SS) Last edited by Adger Smith; 01-29-2021 at 07:47 PM. Reason: add%

01-31-2021, 04:00 PM	#8
gmonde Senior Member Join Date: Nov 2007 Posts: 615 Likes: 56 Liked 165 Times in 59 Posts	Re: Length of header primaries i have built a few sets of headers for street cars,stockers and chassis cars ,, in a stocker engine bay is very challenging to map out your equal lengths, but being careful not to create restrictions by trying achieve equal lengths ,i always try to plot out the smoothest paths with out to many bends and using bigger radius bends where i can , collector sizes are like camshaft choices, you can get close but to find that perfect combo dyno testing is key to getting the most out of the combo, but as you know there just isn't enough time to test everything in my opinion you want to focus on what you can build for torque ,,most carbureted stocker engines are done making power between 6200-6700 ,, torque around 4500 -5000,,, gmonde