I recently put the magnaflow high-flow cats on my STR, the ones recommended by others in the forum combined with the x-pipe and resonator deletes. It sounded like a terrible honda. Went back and replaced mufflers with flowmaster...then magnaflow. Took out x-pipe and put in resonators. Now at idle an low acceleration it sounds good but under medium acceleration it still has a rasp that doesn't sound good.....has anyone ran into this before? How did you fix it?


Also....starting to get rpm jumps slightly when not fully warmed up but they go away once warm....usually only jumps 100 rpms for about 10 seconds and then goes away.

 

Do you perhaps have exhaust leaks?

 

I don't believe so but I am still going to take it into another shop to have them check for any.

 

bgs, I installed almost every imaginable muffler combo after hi-cats and x-pipe install. 1. install magnaflow Tru-X center muffler (a muffler in an internal x-pipe configuration. This'll take the rasp out of her. 2. see how you like it. If too loud (even with the Magnaflow's), then replace with a pair of Walker Dynomax VT mufflers ($100/each). This'll definitely quiet her down in and out. When under full throttle, they open with more flow than most flow throughs. These are going on my 03 STR soon.

 

I'm not a big fan of my Magnaflows and their sounds. If I could do it all over again, I would have left the OEM cats in as they were already pretty small, and just thrown on a Mina Gallery axle back and called it a day.

I have had high end exhausts systems in e past on other cars (Eisenmann, Prodrive) and they are built to make a wonderful sound. The Magnaflows are universal so they are not built to work with your car to make any sound.
Plus the welding instead of bolt on always leads to leaks. I so wish I wentq Mina Gallery axle back and never installed by Magnaflow resonated x pipes and cats.

 

I am almost on the same page as under pressure, I wish I just would have bought the catback and called it a day. I recently bought a borla 400287 and its two inches two long to work, next up is the magnaflow 11385 that is only 14 inches long (looks like the max is 17). Hopefully this will sound better than my current 11387 which I am not happy with.

OP: I am surprised u installed just the x pipe with not a full muffler unit as described above. I did the same thing and complained with a video earlier this year, looks like you skipped my post, sorry!

 

The Magnaflow Tru-X center muffler and Dynomax VT will quiet her down. Mine runs the hi-flow cats and Tru-X. The Dynomax VT are next. Or...go to Magnaflow's 50 state legal cats. These outflow stock cats and are much quieter than the hi-flows.

 

Rasputin, I have the Borla 400287 on my R and the muffler shop didn't have any problems installing it.

 

goblue, do you have the stock rear boxes, because I do and thats the problem? If not then that would make sense. I went under there to look and see what the mechanics were saying, and they were right, if you utilize the stock rear boxes, where the two tips exit out of the stock resonator(or new muffler) is where it gets tricky. For the 400287 to fit, you would have to redo the pipes that connect to the rear boxes ($$$$$$) from the muffler, because moving it toward the front of the car would have it knocking into the body if you didnt. Hopefully that make sense. So a 19inch 400287 is too long, but a 17 inch muffler would be ideal.

 

That makes complete sense... and yes, I'm using the Mina axle-back exhaust.

 

Just got the magnaflow 14385 installed (11385 is cheaper and not polished, same size) and I am very happy. Haven't had a chance to get out and have someone else drive it so I can hear, but, from inside the cabin it sounds very good. Very mustang like below 2krpm with a subtle burble. Above 2.2krpm it sounds V8 M3 esque. Will try and get some vids here in the next week. OP get this installed, you will be happy!

 

Rasputin, that's the setup I'm running and really enjoy it as well. Have had compliments from other people that have heard it running as well.

 

rasputin, are those 49 state magnaflow hi-flow cats or magnaflow 50 state? If yes or no, what diameter (2.25" or 2.5")?

 

The 59775 or 59975, whatever that part number is, is what I have for 2.25.