Exhaust Rasp HELP!

[BlackBetty3.5]

Hello to all fellow 4th Gen SHO owners!

This will be my first post and I am looking for guidance for my exhaust.

A little background, I had the car straight piped out the front of the rear wheels. This sounded AMAZING IMO. I even got the popcorn effect slowing down and overall sounded very aggressive obviously. This however created a ton of interior resonance and as this is my DD, not very professional. Thus began my quest for a middle ground for a tamed roar.

I have LMS catless DP plus Corsa 2.5" catback exhaust system installed (essentially straight piped till the muffler) among other items pushing me close to ~425 hp @crank. At idle and up to 3k RPM the car sounded magnificent, but, as soon as you hit WOT or anywhere in the range of 3k to 4k RPM I got this civic sound that crushed my soul. (no offense to those that enjoy "that sound" its just not my style) Especially after all the money that went into that setup for it to sound the way it did was very disappointing. After a bit of research I threw some Flowmaster super 40's on, which did increase the overall growl of the car and I do enjoy them over the corsa mufflers. This helped the rasp at WOT but it definitely is still there.

Now for my flood of questions.... Is the rasp there because the exhaust is clamped? should I weld the connecting points? Is there a better muffler setup or resonator to eliminate the rasp?

Any help or guidance is very much appreciative and I do apologize if there is a thread on this already, I looked but didn't find any answers.

 

[Johnbigdog]

You might want to search the forum for "J-Tubes" or Google this. Basicly you tune the exhaust to get rid of a certain tone frequency.

 

[SHOdded]

SilverSHO has added a tuned resonator to his SHO.

I believe tho the source is the catless downpipes, very common across brands.

 

[BlackBetty3.5]

I guess I should specify the sound maybe. The sound coming out is almost perfect. I tip my hat to Flowmaster as they can make a good muffler. It's not the "tone" or drone of the exhaust necessarily but and "tang" in the higher RPM's that I'm hearing almost like it overpowers the sound/tone/drone. Like the 4 bangers you see driving around town that sound like they have "just married" tin cans dragging behind the car. Is that something a resonator would eliminate/dampen?

 

[limited02]

What about adding a Flowmaster race muffler as a mid-pipe?

Something like this: https://www.jegs.com/i/Flowmaster/3...MIt8KDtIqs2wIVAQRpCh3pFQBwEAYYBCABEgKzlvD_BwE

 

[SilverSH0]

I guess I should specify the sound maybe. The sound coming out is almost perfect. I tip my hat to Flowmaster as they can make a good muffler. It's not the "tone" or drone of the exhaust necessarily but and "tang" in the higher RPM's that I'm hearing almost like it overpowers the sound/tone/drone. Like the 4 bangers you see driving around town that sound like they have "just married" tin cans dragging behind the car. Is that something a resonator would eliminate/dampen?

Technically Flowmaster mufflers are simply helmholtz resonators (I believe that's the same thing as J tubes referenced above) packaged very closely together to tune out certain frequencies. A proper resonator could reduce this tone and lessen that higher tone you're hearing. The hard part will be determining what frequency you want to remove.

 

[Jordan Arthur]

I guess I should specify the sound maybe. The sound coming out is almost perfect. I tip my hat to Flowmaster as they can make a good muffler. It's not the "tone" or drone of the exhaust necessarily but and "tang" in the higher RPM's that I'm hearing almost like it overpowers the sound/tone/drone. Like the 4 bangers you see driving around town that sound like they have "just married" tin cans dragging behind the car. Is that something a resonator would eliminate/dampen?

I also have the flowmaster super 40s and love them and have put flowmasters on all my vehicles. I too believe the rasp is from the catless dp's as i just have the mufflers and no dp's and i just have that nice deep growl and low drone at highway speed which some may hate but i don't mind at all.