View Single Post
Jim2 Jim2 is offline
7.0:1 > 11.3:1
 
Join Date: Oct 2003
Location: Calgary
Posts: 1,685
Garage
Over and above what Ben said, the headers we use don't have sufficient expansion points to allow for material growth at operating temperatures. By comparison aviation exhaust systems have bellows or slip-joints at most multi tube unions or collectors. Our header tubes are welded to the collectors, and have minimal usage of expansion joints. Too many rigid mounting points as well.

From room temp to 1600F, 12" of stainless tube can grow upwards of 1/16" and is subject to continuious variations from 900F at idle to 1300F cruise, to 1600F on boost, so the header temps are changing constantly while driving, as a result they continously change shape to a minor degree, and if there are limited expansion points, they eventually develop cracks.

On a different note, some advertisments I read claim to have turbo headers made from "aviation grade 304 stainless". 304 is not (never) used for comercial aviation exhaust. I guess the statement helps sell product. Aviation is 321, it demands a price premium because thin wall 321 tube only seems to be used... in aviaiton exhausts.
Old 11-03-2006, 06:42 AM
  Pelican Parts Technical Article Directory    Reply With Quote #38 (permalink)