I found this while I was going through the Evo how-to's.

https://www.evolutionm.net/forums/ev...e-flapper.html

I wonder if the RA's muffler is the same..

Does anybody want to be a guinea pig? lol

 

Well if you screw up I have a Ralliart exhaust just gathering dust for you to replace

 

LOL Would it be free?? haha
What exhaust do you have on right now?

 

Damn things so heavy it would cost a fair amount to just ship it to Florida from here! lol


UR catback

 

Yeah lol I guess that wasn't such a good idea...lol

 

That sounds nice. I'm pretty sure our muffler is exactly the same. The only difference between our and the X is the pipe route b4 the muffler. I think you should do it and report back to us

 

Sacrifice one for the whole team huh? lol

 

Cut this hole too small. Almost made it too wide.



Cut a flap about 2 inches on the bottom, to make it easier to cut the tube.



Inside Shots:





No noticeable difference in sound or power. I would like to get it dyno'd but alas I have not the time.

If someone wants to donate a muffler, I'd like to try capping off the ends of the tube I cut, removing that flapping door, and capping off the rest of the holes inside the muffler.

Took about an hour and a half all said and done. This includes welding and waiting for the paint to dry.

edit: As an idea how about making a small h-ish y-pipe from the inlet directly to the outlets. Though that would probably defeat the purpose of the muffler it self. Unless you wanted that stock look.

 

I did this and there is definitely a difference in sound. You need to block off the part that goes around to the flapper. For more sound I cut off my stock resonator.

 

To amend an earlier statement, I have noticed an increase in torque.

 

Stock resonator?? Is that he part thats right before the stock muffler??

 

But no difference in sound? Outside and in-cabin sound is not different at all?

 

Hm... If modifying the stock muffler would make a difference in torque, even if it was a little bit why wouldn't any of the other performance axle back mufflers like ultimate racings wouldn't see any gains??...

 

It would...but the performance gained from any axle-back is probably negligible.

 

Nothing noticeable to me anyways, defiantly a gain in torque though. I drive pretty consistently so I can't say that the increase in torque is mashing the pedal harder.

I'd like to add, that because I didn't block off the any off the open holes, and just cut the pipe. Is probably why I didn't notice an increase in sound. If I had blocked off the inlet to the muffling portion of the muffler I would have noticed a difference in sound, along with a greater increase in torque. I may reopen the muffler at some point and make a lower case "h" to make it more of a direct flow.