I posted this in the Pipes section but didn't get any responses.

Any of you guys know if you can take the diameter of a muffler and open it up? Like go from a 2.5" to a 3" inlet/outlet? I've searched google a couple hours but haven't had much luck. I'm upgrading to 3" exhaust but really don't want to buy new mufflers, especially when I got these less than 2 years ago.

 

The only way I know is to get the 2.5" to 3" adaptors . I mean if you took the time to cut out the 2.5" inlet/outlet tubes cut new holes in the ends and weld in new tubes maybe but not worth it in my book . And you would likely mess up the tune of the muffler.....

 

What dawson said... Plus I can't imagine what motor you've got in mind that needs 3" full length dual exhaust...

 

cut them flush with the case then use a grinder to open the hole up and weld in a 3 inch piece of pipe

 

I have seen cases where mufflers being to big cause a lose of horse power because its to much flow.

 

he'll be just fine with 3 inch, he has a 351 stroker not a 4 popper.

 

See sig.

 

Thats what I had planned on, I just didnt know if the internals of the muffler was built differently.

Anybody used one of the exhaust cut out kits?

 

My question isn't so much about whether or not it will hurt performance (though I think the argument has some merit), but more about if it's worth the trouble on anything short of a NASCAR motor.

I do remember reading some stuff about how exhaust gases contract as they cool in the pipe, thus loosing velocity, so in some applications you're better off to reduce your pipe sizes down in stages the further you get away from the headers. The intent being to maintain that velocity and increase scavenging. Again... This was geared toward race car type of stuff.

If nothing else, on a street car, I wouldn't go through the hassle of fitting up 3" TAIL PIPES. Turn it down in front of the axle or go with the regular old 2.5" tails.

 

Ive known a couple guys to run 347's with 3". Depends on the application