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Discussion Starter · #1 · (Edited)
Hey everyone, i had muffler delete for a while and do miss the torque at the low rpms, will adding two resonators (one for each side of the exits) even out the torque curve? will i notice the loss in torque? im not talking about any special resonator, just universal resonator.
if anyone has done this, how was the sound?
 

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Can't speak to the sound, but to power....it depends. By resonator, are you talking about replacing the rear muffler with a glasspack straight through muffler? I will assume yes for this reply.

First I think it's important to understand why changing your exhaust can have a negative effect on performance if not done right. You'll often hear that you need backpressure to generate torque. This isn't true. When one of your cylinders is on its exhaust stroke, there's a short time near the end of the cycle when both intake and exhaust valves are open. The hot exhaust rushing out creates suction on the intake valves helping to pull fresh air in for the next cycle. This is known as exhaust valve scavenging.

When you increase the diameter of the exhaust pipe, fluid mechanics dictates that the velocity of the exiting exhaust gas will slow down compared to with a smaller pipe. This reduces the suction on the intake valves.

Backpressure is the resistance the gas encounters as it travels through your exhaust. Therefore, backpressure is bad for performance.

The trick with a performance exhaust is to reduce as much backpressure as possible without sacrificing exhaust gas velocity.

In your case, it should help performance provided that you don't go overboard.

Do keep in mind that yes the skyactiv is a little different than other engines and mazda did an excellent job with designing the exhaust in the 3 performance wise.

I'd stick with a smaller one for sure.
 

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Discussion Starter · #4 ·
yes, i did see that post @minsanity, thanks for that, my question though was about replacing the muffler with resonators. and zero gravity, thanks for the post, i will probably go with magnaflow resonators, will upload video and write about the performance when i do it. Thanks a lot for the response!
 

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*The Electrician*
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See my thread for info on using a resonator to replace the muffler(link below), it has been done by a few others as well. There are times I want to say I have lost power in this process but I cannot prove it without doing dyno testing which I cannot justify over such a small difference. If I have lost any power its extremely minimal, and I gained what I wanted which was a good exhaust note so I cannot complain. I have not noticed any changes in my MPG or in throttle response ect. If you think your missing power and want it back, my advice, go back to the oem muffler.

http://mazda3revolution.com/forums/...rmance/203634-custom-exhaust-coming-soon.html
 

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Discussion Starter · #6 ·
@Midnightsky228 thanks for the link, and, one way to see if u lost power, if you have the tools, put back the muffler, do a second gear pull from 1500rpm to redline and have someone with a stopwatch, then to the same without the muffler.(only if you wanted). either way, ill pull the trigger and do it. will later post about what i think about replacing the muffler. thanks again!
 

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Daily Driver
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Instead of starting a new thread, ill just post here since this is kind of what i have in mind.

Is there a difference between glasspacks and resonators? I was thinking of doing the same thing that op was going to do, except using dual magnaflow glasspacks instead of resonators to replace the oem muffler. I would hope for the exhaust note to be slightly louder than stock but still have a deep, controlled tone with minimal drone. I love the sound of the single-exit vibrant resonator setup but its just a tad too loud for me. I guess my options would be:
-dual magnaflow glasspacks (part no.18115)
-dual vibrant resonators (part no.1790)
-single exit 18 inch vibrant resonator (part no.1791)
 

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Discussion Starter · #8 ·
update: i bought the ultimate racing axleback, the reason i lost torque is that the piping was too large, if you dont want to lose torque get same size piping, or no more than 2.5 inch. adding a resonator or glasspack wont hurt or gain anything, it would be just to tone the exhaust note.
 

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update: i bought the ultimate racing axleback, the reason i lost torque is that the piping was too large, if you dont want to lose torque get same size piping, or no more than 2.5 inch. adding a resonator or glasspack wont hurt or gain anything, it would be just to tone the exhaust note.
Cool.. I plan on getting that one as well.

How are you liking it so far?
CK
 

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20180805_104941.jpg
Here is a good old school book.

The flow of exhaust, when intake and exhaust valves openings overlap, helps intake air enter combustion chamber. Exhaust velocity helps improve scavenge flow in intake, and is RPM dependent.

I play with kitcars, and develop ignition and EFI systems from scratch. I find exhaust system changes require tuning changes. Using data logging of vital engine parameters, I find it possible to retune engine, and also determine benefit of changes. I found by using dual muffers, with a spring loaded relief, low end performance, and high end is achieved without compromise.

I have not messed with my mazda, I like it as it is.
 
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