Custom Exhaust Magnaflow (Hopefully not too loud)

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polskifacet

New member
Hey Guys,
Just wanted to share my ideas for the next guy that's looking for a tame, cheap, but solid exhaust solution. I don't want to pay $1000 for something that is 100% performance driven. As my 2013 SHO is a daily, I just wanted to optimize the stock system. What I have planned out is removing the 3rd cat while keeping the resonator (so it doesnt resonate!) and installing some stainless steel Magnaflow XL 3 mufflers while reusing stock tips (saving another $160). I got them for $67 a piece on Amazon.

http://www.amazon.com/gp/product/B000COTD6G

The other cost will be the fab work and materials which should run about $200 depending on fitment etc. I will post plenty of pics and sound clips after I get it done (hopefully soon!).

Magnaflow XL 3 2.25" offset/center
Doesn't look like a $1000 polished exhaust of course but stainless is stainless and its going to be under the car for Chicago winters.
2015-09-14.jpg
 
Just beware of getting it raspy... Third cat delete does that often... Many have had it replaced after trying without... Experiences have varied.
 
BiGMaC said:
Just beware of getting it raspy... Third cat delete does that often... Many have had it replaced after trying without... Experiences have varied.
Click to expand...
I'm banking on not having a straight through muffler and the stock resonator will keep that horrid rasp at bay.
MUFFLER10-1.jpg
 
Just to add to the discussion...On my last SHO I'm somewhat embarrassed to admit that I cut a round hole in the bottom of my stock mufflers and tried pulling the packing out of them to see if that would change the sound.  I didn't touch the rest of the exhaust and plugged the holes back up with stainless hole plugs sealed with high temp RTV and painted the whole thing black.  FYI for anyone who has thought about it - In my opinion it was a total waste of time as I don't think it changed the sound at all. They were offset as well inside.  Maybe it sounded better outside the cabin but inside I couldn't tell the difference.
 
ecoboostsho said:
Just to add to the discussion...On my last SHO I'm somewhat embarrassed to admit that I cut a round hole in the bottom of my stock mufflers and tried pulling the packing out of them to see if that would change the sound.  I didn't touch the rest of the exhaust and plugged the holes back up with stainless hole plugs sealed with high temp RTV and painted the whole thing black.  FYI for anyone who has thought about it - In my opinion it was a total waste of time as I don't think it changed the sound at all. They were offset as well inside.  Maybe it sounded better outside the cabin but inside I couldn't tell the difference.
Click to expand...

LOL! Bro ..... Bro .......
 
Do not use these chambered mufflers! Drone at 2k. Called Magnaflow and they said these have no packing. Chopping them off and got the regular straight through Magnaflows. #11256
 
After talking to Magnaflow, they said to put in the longest straight thru mufflers I can fit. The XL Turbo doesn't have any packing material so it doesn't absorb any of the low frequencies.
 
Final Setup: 3rd kitty removed, stock resonator, stock piping Magnaflow 11256 mufflers (longest that would fit), Ebay 2.5 to 4 inch tips. (2.5 inch mufflers ect. fit well with stock piping after slight hydraulic expansion of stock piping).

Props to Corwell Customs in Plainfield.

exhaust1.jpg

exhaust2.jpg

exhaust3.jpg

exhaust4.jpg
 
FYI you need the fiber glass packing to keep the drone at bay. All exhaust systems will have a drone. There is no magic combination to get ride of drone 100%. The best you can do is get mufflers that will keep it to a minimum. I just mentioned on another thread that I still get drone between 2k-4kRPM, with a load of going up a hill. It sounds meh.  (only have the corsa). Ford put the right combination of mufflers, resonators, and cats to keep the sound tame. When you open the exhaust, you open the sound, therefore you get more flow.

Sound vs HP, you pick.
 
14SHOCAR said:
FYI you need the fiber glass packing to keep the drone at bay. All exhaust systems will have a drone. There is no magic combination to get ride of drone 100%. The best you can do is get mufflers that will keep it to a minimum. I just mentioned on another thread that I still get drone between 2k-4kRPM, with a load of going up a hill. It sounds meh.  (only have the corsa). Ford put the right combination of mufflers, resonators, and cats to keep the sound tame. When you open the exhaust, you open the sound, therefore you get more flow.

Sound vs HP, you pick.
Click to expand...

90% agree, my only gripe is highway speed drone which makes the car un-drivable for road trips etc. First set of mufflers had a weird sound and attenuated 93 hz. The long magnaflows I got the second time around definitely do a decent job in the 85 hz to 120 hz range, which is like 55mph to 80mph for me. In Chicago for a DD, cutouts aren't an option because of winter. What I learned from this project is get the longest packed mufflers you can fit and you get all of the performance benefit and a tame sound. Note: WOT the exhaust becomes virtually silent above 3k, good for now drawing much attention. Sound vs HP isn't a linear curve. Packed Muffler length vs Sound is. As long as its straight thru, HP is a constant.
 
Hey Guys,
Finally got my exhaust sounding like what I was expecting. A big part of the problem was the stock resonator, seems that it is basically a straight pipe, I don't see any perforation in the tube etc. that would allow the sound to go to the body or packing of that stock resonator. Also the two banks are not connected so in my case it was running like "true duals". Here are some pics of the third revision and how the innards of the stock pieces look. The drone is extremely tolerable now, the X inside the magnaflow muffler that I replaced the stock resonator with, it definitely makes the exhaust sound as one vs with the true duals you could kinda tell that the banks were separated, more of a lugging sound.

Magnaflow Resonated X welded in
3rd%20muffler.jpg

Inside Magnaflow Muffler (Resonated X)
inside%20X.jpg

Awesome TIG welds
tig1.jpg

Stock CAT
stockcat.jpg

Stock Res
stockres.jpg
 
Is this the same place you took it to originally??must admit those are some professional quality welds to say the least,enjoy.  Z    :thumb: :thumb:
 
ZSHO said:
Is this the same place you took it to originally??must admit those are some professional quality welds to say the least,enjoy.  Z    :thumb: :thumb:
Click to expand...
X2!  Looking forward to an updated sound clip, polski, you sure know how to build up the anticipation!
 
That first sound clip was awesome! Exactly what I would be looking for.  I had Magnaflow's on my Marauder and I miss having a daily with an exhaust note.  Just a muffler change would probably get me what I'm looking for.  To bad these engines don't "sing" worth a damn.  6200rpm is pretty low.
 
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