I have a 4cyl, sch40, mild steel log on a 3/8" flange that supports a t25. I'm having one or two bolts that I have to keep my eye on more often than others for backing out. I'm prolly gonna go to stainless allen screws and drill/safety wire them but I'd still like to know if it'd help to put any cuts thru the 3/8" head flange to take any stress off anything? The DP and entire exhaust are pretty lightweight, just 2" mild to a little turbo muffler and a dump. Only about 5' long. I do only have one hanger though, its at the back of the muffler. Is this too much weight pulling on the log mani?

#ad

 

I did have the muffler pop out of the hanger once while out four wheeling and now that I think about it, it wasn't too long after that it blew the gasket out. For a few minutes the entire weight of the muffler, DP, turbo and all were hanging of the manifold. Regardless, I'd still like to know the science behind cutting flanges? Is it worth doing? I'm gonna have it off to reseal it anyways.

 

I can't tell you if it's worth doing or not, however the basic idea is it lets each primary move / flex / expand at it's own rate.

If it's the rest of the exhuast creating the issue I would tend to think it would make it worse not better. What do I know though i could be wrong, I have been before lol.

 

I guess I understand the theory behind it but not so much the specifics. Should I go between each cylinder or just one cut up the middle two? Should I cut thru bolt holes?

 

Just make the bolt holes larger from the middle of the flange to the outside, to allow the flange to grow. No need to cut anything. No need to modify the inner set of holes. Make sure the flange is flat while you are at it.

 

You know what, I've heard of that and I totally forgot. Thanks. Some of the bolt heads are touching the very edge of the weld to the primary in certain holes so IDK how effective that will be for those ones. I'll wallow out the holes, switch to stainless allen heads, safety wire, yada yada, before I run a band saw thru it. Thanks for the replies

 

On Mustangs I know the Mac shorties leaky like a SOB with their individual flanges compared to JBA, Bassani, BBK.

 

I wouldn't cut it. Just get it rresurfaced and add another hanger before the muffler.