Jump to content

Header Flange to Primary Transition

Recommended Posts

It’s been a while since I’ve posted here but there’s always good technical knowledge on this board.  This is not Z related but a header question in general.  I’ve got a set of BMW headers that doesn’t have consistent flange to primary pipe transitions.  There are gaps between the primary pipes and the ID of the flange where ideally it should be flush (welded on the backside).  Most of them are close to flush but the worst gap is about 1/8”. 


My question is should I go ahead and use them as is or should I attempt to fix the gap?  Can a high temp metal filler be used to fill the gap?  I don’t really want to go that route but maybe someone has it before and has some feedback.  If I have to weld to fill it I’d rather send the headers back.  I’m sure the gap will have some effect on flow and performance but would it be enough to not use the headers?  Keep in mind I’m not looking to extract maximum power out of the exhaust setup.  I’m mainly wanting to get rid of the factory headers that have the cats built into them.



Share this post

Link to post
Share on other sites

I agree, although I might be a little concerned about it pulling or twisting or something. On a few eBay headers I had like that the gap area thinned out and wore down and broke/cracked over time. I'm not sure how it is held on the back/outer side, but I would be a bit concerned unless the manufacturer can tell you otherwise. 

Share this post

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Create New...