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1/2" or 3/8" turbo header flange

5K views 16 replies 12 participants last post by  michaeld 
#1 ·
Redoing headers for new heads, headers MS and I have new 3/8" MS flanges.
Should I spend the extra money for 1/2" flanges?
Thanks, J
 
#2 ·
Do the headers support the weight of the turbo? The thicker the better no matter what. Thicker flange won't flex which means you won't have gasket sealing issues.
 
#3 ·
Either will work, the 1/2" will offer better sealing and are less prone to wrappage.
 
#8 ·
I have used 3/8" MS on several builds and never had a leak.

I always support the turbo independent of the headers and I use a flex joint after collector.

IMO 3/8" is all that's needed. I am careful to keep them flat while building and don't build in any preload or stress. After complete I plane the flat surfaces to get rid of any small imperfections.
 
#10 ·
Thanks guys.
I already have the TFS 3/8" MS head flanges for the TFS High Ports, just wondering if it would be worth it to find 1/2".
Headers will be MS for single turbo. Cross-over will have flex joint and turbo supported off frame rail.
Any source of 1/2" MS High Port flanges?
-J
 
#11 · (Edited)
there is no reason to go thicker then 3/8" unless you are using stainless flanges (which will warp more then mild steel and thus need to be thicker)

the header flanges should not be supporting any turbo weight at all (the turbo needs to be independently supported or your tubing joints will start falling apart after a few heat cycles)

IMHO 1/2" just makes it more of a PITA to get hardware in/out. I'd say keep the 3/8" and have them nickel plated or coat your headers. Just make sure you bolt the headers down when welding the tubes to the flange, and check afterwards to make sure there are no low spots..

Also if you insist on 1/2" flanges, send me a gasket or a sample flange and i'll cut them on our waterjet. turnaround time is 1-2 days with a sample.
 
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