I'm considering the idea of custom making a s-pipe back exhaust with 2.5" piping and Magnaflow muffler. I want to get an extra hp and give the car a deeper sound than the current setting
(ricey megan header with stock exhaust ). However, I need to keep my car as quiet as possible because I work with sales and clients don't appreciate if I arrive at their parking lot with a loud car. The current setting sounds bad at full trotle, but is pretty quite at lower rpms. So, I'm in doubt if I should use 2 mufflers or only 1. Here are what I have been thinking about.

OPTION 1:
2 mufflers
One 4" round x 18" long in the middle of the car (magnaflow part# 10426) and a 4"x9" oval x 14" long on the end of the exhaust (magnaflow part#13236).
OPTION 2:
1 muffler
One 5"x8" oval x 18" long on the end of the exhaust and straight pipe from s-pipe back
OPTION 3:
Think of something better.

I'm looking for your opinion and an explanation for your choice. Thanks!

 

Another option would be to go with a resonator/muffler combo, or even throw a highflow cat in the mix. That will keep your tone down without restricting the flow as much as 2 mufflers. This seems to be a popular option.

I have the megan headers as well and they do sound ricey, but I'm going with a 2nd resonator soon so we'll see how it sounds...

 

^^ Thanks for the tip...

anyone else?

 

With either of the first 2 options you will be losing low-end torque. Keeping the cat - or replacing it with aftermarket hi-flow cat - will help the low-end, provide some muffling, and keep you from stinking out your clients (remember you will be cat-less if you lose the cat in mid-pipe too).

If you just want high RPM gains with minimum noise I would suggest the biggest Magnaflow muffler you can fit on the axleback + biggest resonator(s) you can find on the midpipe.

Some folks have had success with smaller Aero resonators. Search for a post by I think it was tCizzler. With a smaller resonator you could still keep a cat on the midpipe.

Just my 0.02 ...

 

I have a Megan header, Invidia s-pipe, 2.5" mid-pipe with hi-flow cat, Vibrant Ultra Quiet resonator, and Magnaflow cat-back. It sounds decent in light to moderate acceleration. There is a little bit of rasp in the higher RPMs during hard acceleration, but it isn't real bad.

http://www.sfxperformance.com/parts/VIB1141.htm

 

Thanks for your .02! I didn't know that the cat helps with low-end... living and learning every day!

 

^^Anything that helps retain exhaust heat will help the exhaust system scavenge better at low rpm's. This includes coated headers, cats, and mufflers which are of the reverse-flow (Dynomax Turbo, Flowmaster, etc.) or chambered/baffled types (like our OEM muffler).

Retaining the heat means the exhaust will cool less as it travels down the pipe. If exhaust is allowed to cool too much it will become dense and heavy and harder for the engine to force out, causing loss of torque.

 

^^^ Interesting... since you seem to know what you are talking about, I have 2 questions for you:

A muffler shop told me to use a magnaflow 4" round as a resonator and a 5x8 as the exhaust. Does the "resonator" part of it make sense? Is a resonator the same as a round muffler?

Q2: If I manage to have the muffler in the middle of the car and a straight pipe from the muffler back, will this make it louder than if I put the muffler on the end of the exhaust?

Thanks for the class

 

my current setup is 2 18" resonators with a magnaflow muffler in the rear (PM axleback/custom midpipe). I've actualy been thinking of removing the 2 resonators and replacing them with a thrush magnum glasspack..... I've been talking with a few people, and they've said that the glasspack will not only quiet it down a little bit, but also help with the rasp that i'm still getting.

 

Mufflers and resonators do different things. A muffler knocks down the overall noise while a resonator is designed to quiet a specific noise frequency you get at certain rpm's, which is rasp.

Chambered mufflers, like our OEM, have resonator chambers built into them to attack (along with the resonator in the midpipe) the specific raspy frequencies that the OEM exhaust would otherwise make. And Toyota's engineers did a nice job - if you hear rasp on an OEM setup you've probably got exhaust damage, like a leak.

Problem is, once you change from the OEM setup - new header, midpipe, axleback - you're dealing with different rasp frequencies and removing or changing resonators. And everybody has different exhaust setups so a resonator that works for one setup won't always help another. No one has engineered a tuned IHE system yet for the tC, so it's hit and miss right now as far as rasp.

But to answer your questions ... to the first one, you'd have a fairly quiet system overall with two straight-through mufflers, but without the proper resonator you'd have loud rasp.

If you only use one muffler - and I'm assuming no resonator (?)- I don't think it matters where you put it. Since it's a single straight-through type muffler with no resonator it would be loud and raspy.

 

^^ What does a resonator looks like on the inside? Would you know where I can get a pic? I tried to search but had no success...

 

 

^^ Thanks Neothin. Now, I thought that this was what the muffler looked like... is this a resonator?

 

the picture description on google said it was :-/

 

lol Thanks!

 

This is actually a straight-through type muffler with (either fiberglass or steel wool) packing inside.

Resonators are hollow inside, essentially a tube within a tube, acting as a cavity to cancel out a specific band of rasp frequencies. The inner tube has perforated holes just like a straight muffler, and they look alike, adding to the confusion. The difference is that a resonator has no internal sound-absorbing packing.

Couldn't find a pic of a resonator cut open but here's a couple links. First one explains how a resonator works as part of a chambered muffler - a discrete resonator works off the same principles:

http://auto.howstuffworks.com/muffler4.htm

This is a good article on exhaust theory, the resonator stuff is about 3/4 way down. Enjoy!

http://www.nsxprime.com/FAQ/Miscella...austtheory.htm

 

good info!

 

Damn! Good stuff! Mid Life, are you an exhaust especialist or a professor? hehehe...

Resu, I really like your picture :lmao:

 

so.... do straight through style mufflers eliminate certain rasp frequencies due to the design AND lower the overall decibel level due to the absorbing material in them?

 

^^Straight-throughs only drop the overall sound level, they won't help with rasp since they don't have hollow chambers.


Nope ... just a voracious reader who finds this stuff interesting!

And like you, I'm going custom exhaust. All the aftermarket exhausts are for looks & sound, I want something quiet and functional - and for a lot less $$. Have a DC header still in the box, not going to put it on until I'm through researching exactly what I want to do ...