UEL + OP + Catted FP + OEM catback = abnoxious rasp?
 

I have put on this combo temporarily and was shocked to find out that the muffler is terribly failing to muffle the exhaust properly. It is silent at idle but when I give it some revs or load, it gets ugly: loud rasp.

Someone said the baffling in the muffler is not designed to handle the increased sound.

Anyone else have this experience? It is so loud that I almost feel like something is wrong with my muffler (yes I checked for exhaust leaks).

you're getting a bad resonance somewhere, but it seems increased flow does that on the stock exhaust.

Robi's car is like that too.

video?

My EL + OP + catted FP + OEM catback has rasp. It doesn't bother me so much though, just turn the music up.

Can no muffler tame a full exhaust setup?

Put the OEM front pipe back on.

Edit - just saw you're s/c. OEM muffler won't like the increase in flow. As others have said, I would think this is the source.

The OEM muffler is a reactive style muffler. It muffles sound by reflecting sound waves to cancel specific frequencies. When the exhaust flow is dramatically changed with something like a header it won't work as designed. OEM mufflers work as a system with the entire exhaust rather than an independent part.

Most aftermarket mufflers are whats called absorptive mufflers. A type of packing, such as fiberglass, is used to muffle the sound. These don't rely on a specific flow/velocity to work properly.

I'm considering swapping out my 3" exhaust with the JDL UEL header due to the noise I get in my head at 70 mph. Also some rasp when I gas it. The loudness I can handle, but the droning noise, windows vibrating not so much.

My downpipe is catted and has a resonator in it, the midpipe has a resonator, and I'm using the offset 5" mufflers on the Nameless axleback. It STILL has rasp.

My question is, would a beefier resonator/muffler like the Perrin 3" catback eliminate my problem? I love my Nameless downpipe... best fitting true 3" overpipe/frontpipe there is with very few bends. Otherwise, I was considering something like the Q300 and going back to 2.5".... but that's a moneysink.



Sorry to thread jack OP. I'm with the other posters thinking the stock muffler is just junk and doesn't have the muffling capability of some of the other aftermarket systems.

Welcome to having a 3in exhaust. Your problem is your exhaust is huge. The Perrin 3in will be really raspy. Darrens car has the 3in Perrin and it is loud n rasp. Lots of noise n drone comes with big exhaust n single wall headers. The drone is mainly coming from your pipe diameter and your header. I guarantee if you put your stock header back on your drone will most likely go away. But you might also be confusing drone with FUCKING LOUD. Ahahaha. Most of our cars will drone at cruise. It's a subi thing. My wifes WRX does it. The built wagon does it. My 11 sti did it. You just have to roll with your windows cracked and love the noise!

Yeah, I just watched a video of a full Perrin 3" with a Borla UEL. Still had rasp. Son of a....

Oh my stock header went straight to the trash can. That thing is possessed. Looks like the only solution would be going back to 2.5" BUT.....

I'll let the dyno make the decision for me. I'll be dynoing my car soon, and if it throws up good numbers with the JDL UEL and the full Nameless 3", then it will sway my decision easily. This is my first big diameter exhaust, even larger than my LS1 Camaro, lol. I'll just wait and see what happens. Worst case scenario, someone will buy this full Nameless system off of me probably for what I paid for it.

The resonator in your front pipe is a Hemholz resonator that works the same as an OEM exhaust to cancel specific frequencies. I'm sure Nameless has the volume calculated to eliminate the drone in the frequencies a stock header produces. So changing that volume may help you eliminate that... I think.

The resonator in your midpipe is an absorptive muffler with the same construction as the ones used in the axleback. With that style more volume equals less sound.

The downpipe/overpipe has a cat followed by a regular resonator. They don't have a Helmholtz option for the 3". Even with the stock header, you can hear some rasp. Check out this stock header video of my system:

[ame="http://www.youtube.com/watch?v=XrxfZmRVILY"]Nameless Full 3" Exhaust With 5" Offset Axleback - YouTube[/ame]


The lower rpms are okay, but the mid range is where it hits. The JDL UEL definitely brought out more rasp due to losing a cat and the thinner walls of the header.

Pic of OP/DP:

http://i1133.photobucket.com/albums/...psc267a5d8.jpg

As you can see, the resonators aren't too large, but they aren't very small either.

^^ sounds great to me

The resonators/mufflers look pretty small. So I'd say the perrin catback would be a little quieter because of the larger volume resonator and muffler. But I don't believe that would solve your drone issue.

In the process of building my 3" exhaust with a high flow burns 2 stage muffler. Hoping there won't be much drone or be abnoxiously loud. Will post results once its done. :thumbup:

http://grassrootsmotorsports.com/med...=400&width=700