Long tube headers - what length is considered "long"?

[rustrocket]

I've ultimately concluded that i'm going to have to fork out a chunk of change for some custom long tubes in my ls2 wagon. I've heard too many arguments that the shorty headers choke up these engines too much and sacrifice power

 

So, when talking about long tubes, is there a minimum length that each tube should be? Is there a point where the header tube length can be too long and therefore detrimental to performance?

 

I like to learn, so please feel free to reference websites or other relevant information.

 

Thanks for your help.

 

-Cameron

[johnc]

For engines in the 2.5 to 3.5L range header primary tube length should be 28 to 32" long. That measurement is from the back of the exhaust valve to the point in the header collector and/or Y pipe where all flow from the primary pipes meet.

 

I don't know if this is true for larger engines. I suspect it is because we're concerned with wave speed.

[WizardBlack]

I'd check with burnsstainless. I dunno if they have it on their website, but in their catalog they have a custom header setup so you can change the length and tune it. Something about using a grease pencil down the side of the primaries and collector. Where the grease converges from melted to not melted is the "proper point" for a collector. They make some pretty high end V8 headers.

[Tony D]

Burns Stainless also has a engineering service which they will lump into the cost / credit you for on purchase of their collectors and tubing when you construct your header.