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Thread: Exhaust questions

  1. #1
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    Default Exhaust questions

    Hey,

    what is the difference between an oval centre section or a circle centre section taht come after the cat on an exhaust?Is it a performance or a sound thing?

    and what does a resonator do?MAke it louder/quieter?add power??

    Thanks for the help...

  2. #2

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    No idea what different shapes do... mostly nothing I would say if the overall pipe size is the same

    Resonators are kinda like mufflers, they use reflection (refraction?) to cancel out sound waves. I think most useful if you have a drone at some rpms etc

  3. #3
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    will the resonator cause a reduction in power?Thanks

  4. #4

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    The big oval thing after the two cat's is the silencer (on the 3 Gen 1)

  5. #5

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    The difference between the oval and round is reduction of noise. The larger the muffler, the more sound it will reduce. Most places use oval to fit a bigger area and have more ground clearance.

    Resonators and mufflers are pretty much one and the same. Mufflers, muffle, resonators reduce resonation, same thing really.

    EG 1: 3" internal, 7" round would reduce noise better than a 5" round. A 7" x 5" oval would work better than 5" round, less than 7" round, but have 1" better ground clearance than the 7" round.

    If you fit 2 resonable size mufflers/resonators into an MPS sytem, you can reduce the sound to under legal Dbs and still make power. With a full 3" system and hi-flow cat.

    EG 2: A quality straight through design muffler will reduce power, but, only marginally. A cheaper "tri-flow" design will reduce power considerably, but reduce the noise alot more.

    Straight though:



    Tri-flow:

    Last edited by 2XS; 15-04-2010 at 08:10 PM.
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  6. #6
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    Default

    Nice job on the write-up 2XS

  7. #7

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    Quote Originally Posted by rogwick View Post
    Nice job on the write-up 2XS
    It helps having worked in the industry........... previously of course.
    Achievements
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    Aust. Quickest and Fastest MPS
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    Another Mazda 3 MPS - Almost fully bolted - Waiting for a turbo upgrade - The weekend hack.
    Toyota Yaris - Coilovers, rollcage, raceseats, harnesses, 18s - Also waiting for a turbo upgrade.
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  8. #8
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    So what is your opinion on chamber mufflers 2XS, I was of the opinion they offered decent noise reduction while maintaining good flow characteristics ?

  9. #9

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    Quote Originally Posted by MattMPS3 View Post
    So what is your opinion on chamber mufflers 2XS, I was of the opinion they offered decent noise reduction while maintaining good flow characteristics ?
    I will never use one on a car ever again. I've dyno'd a previous car of mine (1996 Magna 3.5L) and just changing the rear muffler (tri-flow design) to a straight through muffler, it picked up 5Kw @ the wheels, even with the stock cast headers on it.

    If you ever see flow charts for the two designs, the tri-flow design is very poor. If you look at the setup, the flow changes direction twice in its travel. It's almost like hitting a wall.

    Think of air movement like water, you need large radiuses. Water hugs the inside radius at slow speed and moves to the outside of the radius at faster speeds. I's the same when trying to change direction with air, sharp edges don't work. It also works with intakes too.
    Achievements
    2009 Jamboree Street Compact Winner
    Aust. Quickest and Fastest MPS
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    Proven over the Qtr mile

    Another Mazda 3 MPS - Almost fully bolted - Waiting for a turbo upgrade - The weekend hack.
    Toyota Yaris - Coilovers, rollcage, raceseats, harnesses, 18s - Also waiting for a turbo upgrade.
    2011 AWD Territory - White and Slightly lowered on 22s - The tow car.
    2011 RWD Territory - Black on black and slammed on 22s - The family transporter.

  10. #10

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    If you're thinking about exhaust options, it might help to know that the stock MPS6 mufflers are a piece of engineering brilliance. Their design specifically matches the car to cancel droning and resonance and they do so with a loss of just 4kw more than after market hi-flow mufflers.

    There are two flow restrictions in the stock MPS6 exhaust that have proven to give good gains when dealt with intelligently; the DP is one and it's covered elsewhere in these discussions. The other restriction is the T-piece, which is why I hate twin exhaust outlets on inline 4 cylinder engines.

    If you can get hold of a well-made mid pipe that improves flow at the split, you can gain up to 17kw. By keeping the stock mufflers it will cost a fraction of a cat-back system, it will deliver about the same power gains and it will have none of the droning and noise issues. This configuration has been proven by an experienced race car engineer, but the idea has never gained traction because a bunch of CPe fanboys told the expert that he didn't know what he was talking about. He quickly stopped wasting his time on Mazda development.

    It makes you wonder if the after market suppliers are only interested in maximising their profits, or if they feel obliged to produce products to meet the often poorly informed expectations of the market, even if that means producing products that are not optimal.

    Gone to Volvo


  11. #11
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    I might have used the wrong description there, the design I am thinking of, the gasses enters the muffler through a glass filled perforated tube section, then pass into a centre (expansion) chamber, the exit again through the same sort of perforated setup.

    Better still heres a pic
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

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  12. #12

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    Quote Originally Posted by kmh001 View Post
    If you're thinking about exhaust options, it might help to know that the stock MPS6 mufflers are a piece of engineering brilliance. Their design specifically matches the car to cancel droning and resonance and they do so with a loss of just 4kw more than after market hi-flow mufflers.

    There are two flow restrictions in the stock MPS6 exhaust that have proven to give good gains when dealt with intelligently; the DP is one and it's covered elsewhere in these discussions. The other restriction is the T-piece, which is why I hate twin exhaust outlets on inline 4 cylinder engines.

    If you can get hold of a well-made mid pipe that improves flow at the split, you can gain up to 17kw. By keeping the stock mufflers it will cost a fraction of a cat-back system, it will deliver about the same power gains and it will have none of the droning and noise issues. This configuration has been proven by an experienced race car engineer, but the idea has never gained traction because a bunch of CPe fanboys told the expert that he didn't know what he was talking about. He quickly stopped wasting his time on Mazda development.

    It makes you wonder if the after market suppliers are only interested in maximising their profits, or if they feel obliged to produce products to meet the often poorly informed expectations of the market, even if that means producing products that are not optimal.
    Anybody interested in this particular setup should PM Penguin740, I did this exact setup on his car. DP and mid-section only, retaining the stock rear mufflers. He is yet to dyno the car to see the proven performance gains, but the butt dyno seems to say so.


    Quote Originally Posted by MattMPS3 View Post
    I might have used the wrong description there, the design I am thinking of, the gasses enters the muffler through a glass filled perforated tube section, then pass into a centre (expansion) chamber, the exit again through the same sort of perforated setup.

    Better still heres a pic
    It's pretty much the same as the tri-flow, the gasses enter the chamber and then have to find their own way throught the exit pipe.

    This is about the only design the works with internal baffles, that's why most top-end sprintcars run these.



    Check here for all the designs available.

    furinox.com - Muffler Design

    Note: The sprial mufflers do nothing for noise or power, it's all in your head.

    -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

    Think of sound like this, higher freq. (treble) are directional, lower freq. (bass) is non-directional. A simple offset can eliminate the treble, directional change cancels out bass. If you fit a longer (or more) straight through mufflers, you can get the deep note. Having a large pipe to the rear of the car will cause drone. If you can fit a muffler at the very rear of the car, drone can be eliminated, this is why cannons drone so much, they have a large tip for the sound to resonate inside of and cause drone.

    The stock rear muffler on a Mazda 3 has no restrictions on power. I still have it fitted to my car. I have a twin DP, hi-flow cat and full 3" system with 2 3" straight through mufflers, with the std 2.5" muffler on the rear. This helps reduce any noise I may have gained fitting a larger system.

    -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

    The size of the holes inside the muffler also play a part in producing/reducing power.

    Small holes Vs large holes : If the total area of all the holes is all equal, smaller holes create less turbulence than less larger holes, therefore reducing power loss.
    Last edited by 2XS; 17-04-2010 at 08:16 AM.
    Achievements
    2009 Jamboree Street Compact Winner
    Aust. Quickest and Fastest MPS
    12.3 seconds @ 111Mph.
    Proven over the Qtr mile

    Another Mazda 3 MPS - Almost fully bolted - Waiting for a turbo upgrade - The weekend hack.
    Toyota Yaris - Coilovers, rollcage, raceseats, harnesses, 18s - Also waiting for a turbo upgrade.
    2011 AWD Territory - White and Slightly lowered on 22s - The tow car.
    2011 RWD Territory - Black on black and slammed on 22s - The family transporter.

  13. #13

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    OK.. sorry to dig this up a little

    I'm talking Gen1 MPS3.

    The large oval shaped muffler.. SO: DP...Second cat.. resonator.... oval muffler...then small res/muffler just before the tailpipe.

    Im talking about the oval muffler.

    What is its internal construction? Is it straight through like one at the top of 2xs's post? or is it a chamber type?

    Im getting conflicting info, so only reply if you actually know...
    2xs.. im basically aiming this one at you mate

    Thanks in advance

    Doc

  14. #14

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    Quote Originally Posted by Doc View Post
    OK.. sorry to dig this up a little

    I'm talking Gen1 MPS3.

    The large oval shaped muffler.. SO: DP...Second cat.. resonator.... oval muffler...then small res/muffler just before the tailpipe.

    Im talking about the oval muffler.

    What is its internal construction? Is it straight through like one at the top of 2xs's post? or is it a chamber type?

    Im getting conflicting info, so only reply if you actually know...
    2xs.. im basically aiming this one at you mate

    Thanks in advance

    Doc
    It's a chamber type.

    You can tell this by the hot spot created on the external casing (in the centre)
    Achievements
    2009 Jamboree Street Compact Winner
    Aust. Quickest and Fastest MPS
    12.3 seconds @ 111Mph.
    Proven over the Qtr mile

    Another Mazda 3 MPS - Almost fully bolted - Waiting for a turbo upgrade - The weekend hack.
    Toyota Yaris - Coilovers, rollcage, raceseats, harnesses, 18s - Also waiting for a turbo upgrade.
    2011 AWD Territory - White and Slightly lowered on 22s - The tow car.
    2011 RWD Territory - Black on black and slammed on 22s - The family transporter.

  15. #15

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    ok SO would a straight through muffler of similar size make it much louder?

    Not sure if I should even bother with this..
    Otherwise Maybe the Hooker Auro Chamber as you suggested.. This would be a step up from the stock one at least.. and not stupidly noisy?
    Last edited by Doc; 24-04-2010 at 02:40 PM.

  16. #16

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    Quote Originally Posted by Doc View Post
    ok SO would a straight through muffler of similar size make it much louder?

    Not sure if I should even bother with this..
    It would make it louder. It would make it noticable, but, it wouldn't make it excessive.


    \
    Achievements
    2009 Jamboree Street Compact Winner
    Aust. Quickest and Fastest MPS
    12.3 seconds @ 111Mph.
    Proven over the Qtr mile

    Another Mazda 3 MPS - Almost fully bolted - Waiting for a turbo upgrade - The weekend hack.
    Toyota Yaris - Coilovers, rollcage, raceseats, harnesses, 18s - Also waiting for a turbo upgrade.
    2011 AWD Territory - White and Slightly lowered on 22s - The tow car.
    2011 RWD Territory - Black on black and slammed on 22s - The family transporter.

  17. #17

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    would be interesting to see a cross section of the stock muffler for comparison.. Anyone seen one?

    So 2xs.. what do you think of the Aero chamber on an MPS then? Only exhaust upgrade so far is the full DP with a 100CPI cat.

  18. #18

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    I wouldn't fit an Aero chamber, sometimes it can make the car sound "hollow".

    If you were to replace only the centre muffler, a decent straight through type setup works best. I've used Magnaflow, Race Magnum and hand built ones (not on an MPS, but, on higher HP cars). These types work best, for power and noise.

    The stock piping is suff. for most street driven MPS's. Upgrade the piping only to make peak HP gains. 2 1/2 to 2 3/4 is good enough for 300hp @ wheels. Increased volume also means increased noise (and potentially drone if done wrong)
    Last edited by 2XS; 26-04-2010 at 10:18 PM.
    Achievements
    2009 Jamboree Street Compact Winner
    Aust. Quickest and Fastest MPS
    12.3 seconds @ 111Mph.
    Proven over the Qtr mile

    Another Mazda 3 MPS - Almost fully bolted - Waiting for a turbo upgrade - The weekend hack.
    Toyota Yaris - Coilovers, rollcage, raceseats, harnesses, 18s - Also waiting for a turbo upgrade.
    2011 AWD Territory - White and Slightly lowered on 22s - The tow car.
    2011 RWD Territory - Black on black and slammed on 22s - The family transporter.

  19. #19

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    I think im going to go with a magnaflow straight through unit..

    Thanks for the advice

    And ive read a few things about the aerochambers not having much noise deadening capability..

    Thanks for the advice..

    Doc

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