Finished the install
I finished the install with the MagnaFlow [MF] in place of the stock main muffler. I didn't video the before and after as the sound reproduction is highly dependent on the listener's equipment; thus not making a comparison that objective. Instead I used an app on a friend's iphone that measures decibel levels. I placed the iphone a set distance away (marked the location for replication and installed the MF muffler and took another reading).
I placed the phone about 4' directly behind the exhaust and a couple inches off the ground, it rested on a wood block.
Scorpion and straight-thru exhaust after the cat. = 100-101 dB (@ approx. 5100RPM)
Scorpion and MagnaFlow after the cat.* = 91-92 db (@ approx. 5100RPM)
*This set up mimics the OEM set up: the MF replaced the OEM mid (main) muffler, and the Scorpion replaced the end muffler/resonator
Both registered a peak dB of 108 dB @ Redline.
The test readings are at 5100RPM because: if you have the Mirage motionless and rev the engine (i.e., floor it) it will rev (close) to redline and then fall to 5100RPM and hold, so I had a helper rev it out and hold it while I observed the meter. I can't speak to the accuracy in terms of a true dB level (this depends on the 'quality' of the app), however the same iphone with the same app in the same environment, measured within a couple hours should have a reliable relativity, to the readings. A 9 dB drop is significant as the dB scale is logarithmic.
As for the subjective reading: in the car I cannot say that it is louder than stock. I drove it out thru to redline in 1st, 2nd, and 3rd.
Granted I have been driving around for a little over a week with a ridiculously loud exhaust, so that may account for it seeming quiet, but regardless of that, I spent 22k+ miles with an OEM pipe and this is very, very close to that sound level. I have not heard the car being driven away from me yet to discern if it seems to be louder from that "POV" (outside the car).
So what was the point? Good question.
I was hoping to achieve a little noise increase. I like to hear my vehicles and I was hoping to get some 'sweet tunes' from the triple. TBH, at least for now, on day one it seems that the car sounds close to stock in dB level (I never took an OEM exhaust dB reading), not sure about in tone . At my age I prefer the closer-to-stock sound level rather than an overly noisy and droning set-up (what I had for about a week). With the elimination of the OEM muffler and 'passive' cat. the exhaust would seem to be hands down freer flowing (judge for yourself by looking at the OEM muffler pics in the next post), but I cannot claim that any gains were made in power without a before and after dyno run...
I am happy with the set-up, it has improved the look of the tail-pipe and it has (very likely) improved the flow rate of the exhaust. I imagine that the MF pipe will have a break-in period (it's construction is identical to the Scorpion: a straight-thru perforated pipe surrounded with sound absorption material) and that its sound level will increase slightly over time. Right now though, if one was driven around inside the Mirage I doubt they'd realize it had an aftermarket exhaust. If I did it over again I would likely go with the 4" OD MagnaFlow (I put in a 6"), but in my case, for this type of modification I prefer to error on too quiet rather than too loud. So, perhaps a 6" MF to replace the main muffler and a new tail-pipe (sans any muffling) would be a good set-up too...
TL; DR: put on two aftermarket mufflers in place of the OEMs; have a similar sound level, but likely better flow rate and a definite (IMO) better look and tone.
PICS of OEM muffler and Scorpion tail-pipe follow.
Last edited by Minihaha; 01-03-2016 at 02:38 AM.
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View my fuel log 2014 Mirage DE 1.2 manual: 33.4 mpg (US) ... 14.2 km/L ... 7.0 L/100 km ... 40.1 mpg (Imp)