Are Exhaust Flanges Necessary

[Davo53209@yahoo.com]

I'm going through some frustration in my attempts to fix my exhaust. At this point, I'm thinking about cutting off the old broken flanges from the down pipe to the intermediate pipe, while running them with straight pipe adapters.

My question is if whether or not it's advisable to do this sort of thing. Simply put, are exhaust flanges necessary and what is their purpose? From my point of reasoning, if I just ran the pipes straight & clamped them, I could seal off any leaks.

With that in mind, is there something that would eventually cause a problem if I didn't use the exhaust flanges?

[Frank Lee]

Do you mean where the flex joint or donut goes? Maybe it'll work but then maybe not; in fwd vehicles the engine rocks fore/aft so the exhaust system wants more "give" than longitudinally oriented engines need. If it was me I'd properly fix the joint.

[Davo53209@yahoo.com]

Originally Posted by Frank Lee

Do you mean where the flex joint or donut goes? Maybe it'll work but then maybe not; in fwd vehicles the engine rocks fore/aft so the exhaust system wants more "give" than longitudinally oriented engines need. If it was me I'd properly fix the joint.

Yes on both points, that's exactly what I mean. The question is what would happen? For example, would the exhaust system be to rigid, would I be effecting flow, restriction or back pressure somehow if I straight piped everything? Etc.

[Frank Lee]

I doubt flow would be affected... unless the rigidity causes the system to break again. I think really rigid motor mounts and really flexy exhaust hangars would be needed for a solid repair in that location to last as long as you would like.

[Davo53209@yahoo.com]

Originally Posted by Frank Lee

I doubt flow would be affected... unless the rigidity causes the system to break again. I think really rigid motor mounts and really flexy exhaust hangars would be needed for a solid repair in that location to last as long as you would like.

So the underlying point is that so long as I have flex point somewhere, to say the least...got it.

[Frank Lee]

Well, I think the flex point has to be right there where it was, or darn close to it, in order to best do it's job.

There are a few things to keep in mind:

That the engine rocks- at times more than you would think- and the exhaust pipe has to be able to handle that movement.

That the pipe needs to be isolated from the chassis via rubber hangars or unwanted vibes and noise get in.

There might be a "growth" component too, from when that length of pipe goes from cold to hot, that makes rigid mount bad. But I haven't ever really looked into that. And I know you aren't talking about rigid pipe hangars.