I know this has probably been asked a million times, I'm just trying to get a quick answer.

I plan on getting 2 Thrush Welded Mufflers from Jegs along with 2 JEGS tips and going with true duals. I'm leaving the CATS on and not even touching those. I know the V6 mustangs have stock 2.25" exhaust diameter. I've heard a lot of people on the forums say to go to 2.50" diameter piping.

So my question is, can a shop increase the diameter of the pipe size after the cats?

Thanks.

 

Yes they can. Just make sure if you do that you order the correct 2.5'' mufflers.

 

Just the person I wanted to hear that from. You have the same set up I'm wanting to get. How do you like the sound of the set up? Anything I should kind of be concerned about before buying the parts?

Does your set up sound something like one of these?
http://www.youtube.com/watch?v=n890joNemrc
or
http://www.youtube.com/watch?v=fApTHLHSz_U
or
http://www.youtube.com/watch?v=Xp_T5ojyZyM

 

I think those are all his videos. Almost positive the first one is.

 

I did the same thing to my 1999 mustang too 2.5 inch stainless steel piping all the way back; but I had two Mac mufflers instead. I never heard of thrush before but they sound better than mine! Also keep the cats on! I took mine off and it just made the car lag..but it did sound much louder. But then it won't pass the emission testing. Anyway good luck.

 

I'm not quite sure if the piping for the cats is 2.25" or 2.5", but if it is 2.25", going from 2.25" piping to 2.5" is pointless. Your piping is only as big as it's smallest diameter. I've got LTs, no cats, and 2.5" piping all the way and acceleration did lag some... until i got a tuner. If i had gears it'd be even better.

 

Well from what I've heard by talking to a few people, they say the 2.5" diameter makes the car sound better. I'm not exactly sure why though. Maybe it doesn't restrict the exhaust flow as much, don't quote me on that though.

 

haha yes all those videos are mine. going to 2.5 piping isn't going to really make a difference, you can only flow as much as your smallest pipe allows so essentially, the 2.25 will just be a bottle neck

 

I thought the stock exhaust was 2"? Even if it is 2.25, splitting that from one 2.25" pipe into two 2.25" pipes would still flow better...

 

Stock exhaust is 2.25''. Yes, I agree that sticking with 2.25'' piping WILL be your best bet. I don't think there really is a difference in sound.