I found this over on the subie guys' forums, an awesome 3" to 2.5" flange converter that's also available on Amazon:

3" Downpipe Adapter - Aftermarket DP>OEM Subaru Catback - GrimmSpeed

As a lot of you guys with the top speed exhaust and a 3" y pipe know, some of the rasp you get is from having the uneven piping diameter from the 3" y pipe to the 2.5" top speed y pipe. This can be pretty annoying considering the top speed on its own has no rasp and very little drone. And welding in a 3" to 2.5" exhaust reducer can be a hassle and possibly expensive at a shop as well, unless you can weld yourself. Something like this adapter that you can slide in between two flanges is so much easier.

If you buy this you're gonna need to cut off the 2.5" side of the pipe sticking out, but it only took me about an hour as an inexperienced dremel-er, haha. Mainly we're using the funnel on the 3" side. I installed this in an hour or two, and just tested it out this morning on my commute to school. There is still rasp and drone but I'd say its cut down by 1/3 to 1/2.. for a $40 part and a 2-3 hour DIY job that seems pretty awesome to me.

 

Is the rasp really bad because I'm about to buy fast intentions rhfcs, manzo 2.5in to 3in outlet y pipe and top speed y back exhaust and this is making me think twice on the y pipe

 

It livable but not what you'd want if you just dropped 2-3K on an exhaust setup. Though the performance gains imo are worth it. If I had known in the future that I would be getting ART pipes and a 3" y pipe I probably would have gotten a 3" catback as well.

 

I would love a full catback like Ark but I'm getting one heck of a deal 950 barely used full setup including the fi rhfc. If I had the funds I know someone selling art pipes locally to me for 500 and I would of got the ARK but right now can't be spending that much so I figure might as well get the setup for 950. I have Stillen gen 3 so this will be my last power mod and then tune and call it quits

 

What do you think about using a magnaflow resonated x pipe instead of the y pipe and paired to the top speed y back?

 

Nice find! I ended up going back to my OEM Y-pipe since the rasp was pretty bad w/ my resonated test pipes going into a new 3" Ypipe then into my 2.5" TopSpeed. Now my rasp is completely gone. Not sure I want to introduce any rasp as I love the way the Resonated TPs sound w/ my Top Speed and OEM Y. If I could install this on the 3" Y that would be ok since I could go back to my OEM Y if I didn't get enough rasp reduction, at $40 it's worth a shot, and my OEM Y is SO shredded it would be nice to put that 3" one back on. Thanks a lot fro posting this up. Do you have any pics of the new connection?

 

I'm going to see Motordyne art pipes right now and pairing it with top speed y back and stock y pipe

 

I think that's going to sound awesome, look forward to your impressions.

 

Interesting thread. Trying to figure out which 2.5in exhaust I want to pair up with my 2.5in Berk's HFC so I can reduce some of the rasp.

 

Killer find.. I have a Top Speed Y to the stock mid pipe and then Manzo mufflers. The rasp is pretty annoying.. A more expensive ($260) fix would be getting the Megan Mid pipe which is 3".. I think I'm going to swap in the OEM Y pipe again and see what the noticeable ratio is from power loss to rasp elimination. I'll make a before and after video like I always do on my YouTube channel with any mods.

 

Sadly I did not take a picture of the connection where the adapter goes, but you can imagine fairly easily how it would look with that flange having a 1/2" additional flange adapter in between. Also, I have been hesitant to switch back to an OEM y pipe because I've heard how restrictive it is.. but at the same time the prospect of no rasp sounds amazing.

 

Not sure how restrictive the OEM Y really is. It seems like it would be, but TBH when I went back to OEM the car still seemed just as responsive.

 

I might just do that then. I feel like test pipes are the main benefit in full exhaust anyways, and they shouldn't be affected by a different Y pipe.

 

I actually just got my ART Pipes installed with my top speed y back and stock ypipe and it's perfect. The test pipes made my throttle response much better and definitely gained some whp.

 

x2, my resonated TPs gave me the best butt-dyno of the mods I've done, but it's just a Y-back and intake in my case But definitely a best bang for the buck!