Custom Exhaust Magnaflow (Hopefully not too loud)

polskifacet · September 15, 2015, 11:36:51 AM

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.

ecoboostsho · September 15, 2015, 11:55:27 AM

Interesting! Can't wait to hear it and hope it works out great for you!

BiGMaC · September 15, 2015, 11:57:37 AM

Just beware of getting it raspy... Third cat delete does that often... Many have had it replaced after trying without... Experiences have varied.

SHOdded · September 15, 2015, 11:58:57 AM

Looking forward to pics of your project in progress.

14SHOCAR · September 15, 2015, 12:56:13 PM

Quote from: BiGMaC on September 15, 2015, 11:57:37 AM
Just beware of getting it raspy... Third cat delete does that often... Many have had it replaced after trying without... Experiences have varied.

LOL Here's my horror story:

https://www.youtube.com/watch?v=128SB_RY0UQ

BEWARE of the ecoboost RASP from HELLLLLLLLL

polskifacet · September 15, 2015, 03:45:55 PM

Quote from: BiGMaC on September 15, 2015, 11:57:37 AM
Just beware of getting it raspy... Third cat delete does that often... Many have had it replaced after trying without... Experiences have varied.

I'm banking on not having a straight through muffler and the stock resonator will keep that horrid rasp at bay.

ecoboostsho · September 15, 2015, 04:16:49 PM

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.

polskifacet · September 15, 2015, 05:28:05 PM

Quote from: ecoboostsho on September 15, 2015, 04:16:49 PM
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.

LOL! Bro ..... Bro .......

ecoboostsho · September 15, 2015, 06:26:06 PM

For the record it was only a test. I ended up going with the dynomax axle back and was happy with it.

polskifacet · September 25, 2015, 11:55:12 AM

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

polskifacet · September 25, 2015, 03:07:18 PM

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.

polskifacet · October 05, 2015, 10:27:22 AM

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.

polskifacet · October 05, 2015, 10:46:30 AM

! No longer available
! No longer available

14SHOCAR · October 05, 2015, 02:23:22 PM

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.

polskifacet · October 09, 2015, 11:17:26 AM

Quote from: 14SHOCAR on October 05, 2015, 02:23:22 PM
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.

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.