quote:Originally posted by garth66:....... Therefore, the collector flanges should not fatigue and crack since the exhaust, engine, and ZF are all joined together and move together, as one unit.
But the engine and TA don’t undergo the kind of temperature change the exhaust system does. The primaries and remaining exhaust system exhibit thermally induced growth and do so in the direction the tubes are pointing and if you anchor them rigidly, that thermal growth induces a lot of stress. An 1/8” movement of the 180s at the rear of the TA wouldn’t be unusual at all. Depending upon how you have it tied down, through cycles it adds up. Various stainless alloys maintain their strength at temperature better than carbon steel and can be more tolerant to a degree. It’s an even more significant issue in turbo systems and that’s why turbos typically are supported but not rigidly mounted. They always have expansion tolerance, at least the well designed ones do.
Best,
K