2011 MX5 Mod Options and their impact on Roadworthiness
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- Fast Driver
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Re: 2011 MX5 Mod Options and their impact on Roadworthiness
Thanks Regie! I'm guessing the super-q is very similar to your rsq. I hear the super q has less drone though, do you experience any?. Also I ordered the ceramic max power, is yours the same? Do you have the baffles inserted to reduce excessive sound?
BTW I checked with Brian and the ppe catted header does fit rhd as mentioned here http://www.good-win-racing.com/Mazda-Pe ... -0895.html
BTW I checked with Brian and the ppe catted header does fit rhd as mentioned here http://www.good-win-racing.com/Mazda-Pe ... -0895.html
- Charlie Brown
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Re: 2011 MX5 Mod Options and their impact on Roadworthiness
Jassi, here’s my exhaust experience that may not help you now.
I’ve run the GWR max performance header for the last 6 years with the stock midpipe and muffler. It has around 25% more noise than the standard system and would fail an exhaust emission test. The retained stock secondary cat isn’t big enough to handle the engine's noxious gasses. The GWR midpipe cat is smaller than the stock secondary cat.
Six months ago I got a second hand GWR midpipe from Regie, with a raspy noise at 3,000rpm thrown in for free. I found the noise level with the GWR header, GWR midpipe and stock muffler to be double that of the GWR header & stock system.
It was very loud but I thought if I could eliminate the rasp (which I figured was loose baffles), I may be able to live with it. So I inserted some long screws to hold the baffles against the wall of the resonator to eliminate the rasp. Well that failed miserably.
As my car is a daily drive I realised that every car/driver within 300 metres knew if I was on or off the throttle, something that I didn’t want. Then driving to work through the Cross, little kids would dive for cover and dogs bark at every gear change as the pops in the stock system sounded like rifle shots with the GWR midpipe. So last week it came off the car. It is now back to a semi “civilised” sound and a lot more pleasant to drive.
At the track it’s different. I fit a small 350mm long muffler, that’s LOUD. It puts out enough noise to vibrate every panel in the car and undo nuts. On the road, I’d rather fly under the radar.
I’ve run the GWR max performance header for the last 6 years with the stock midpipe and muffler. It has around 25% more noise than the standard system and would fail an exhaust emission test. The retained stock secondary cat isn’t big enough to handle the engine's noxious gasses. The GWR midpipe cat is smaller than the stock secondary cat.
Six months ago I got a second hand GWR midpipe from Regie, with a raspy noise at 3,000rpm thrown in for free. I found the noise level with the GWR header, GWR midpipe and stock muffler to be double that of the GWR header & stock system.
It was very loud but I thought if I could eliminate the rasp (which I figured was loose baffles), I may be able to live with it. So I inserted some long screws to hold the baffles against the wall of the resonator to eliminate the rasp. Well that failed miserably.

As my car is a daily drive I realised that every car/driver within 300 metres knew if I was on or off the throttle, something that I didn’t want. Then driving to work through the Cross, little kids would dive for cover and dogs bark at every gear change as the pops in the stock system sounded like rifle shots with the GWR midpipe. So last week it came off the car. It is now back to a semi “civilised” sound and a lot more pleasant to drive.
At the track it’s different. I fit a small 350mm long muffler, that’s LOUD. It puts out enough noise to vibrate every panel in the car and undo nuts. On the road, I’d rather fly under the radar.
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Re: 2011 MX5 Mod Options and their impact on Roadworthiness
thanks for sharing Charlie! Since you have tried both the gwr header and gwr mid-pipe in conjunction and its loud, i can only hope that the gwr super-q muffler with the baffles inserted does a good job at suppressing the loud rifle shots
As far as emissions, I was warned of the failure to comply on this thread, but also told no one ever checks for it How did you end up in an emissions check - was this part of a mandatory roadworthiness check needed in your case or a letter by EPA, etc.?
Lastly if you've got Regie's mid-pipe then what is he running
i thought he shared his experience on his current setup which is gwr max power, mid and rsq 

As far as emissions, I was warned of the failure to comply on this thread, but also told no one ever checks for it How did you end up in an emissions check - was this part of a mandatory roadworthiness check needed in your case or a letter by EPA, etc.?
Lastly if you've got Regie's mid-pipe then what is he running


- Regie
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Re: 2011 MX5 Mod Options and their impact on Roadworthiness
You will have a nice sound with the SuperQ, it won't be too loud
, remember CB is running a 2.5L and they push a fair bit more air.
Emissions, none of us have had a emissions check, its not part of our roadworthiness checks up here.
Im on my second GWR mid pipe, the one that Phill has is my old one, it developed a buzzing noise in the muffler, i thought the muffler insides had separated from the muffler itself, hence Phill using some screws to secure it

Emissions, none of us have had a emissions check, its not part of our roadworthiness checks up here.
Im on my second GWR mid pipe, the one that Phill has is my old one, it developed a buzzing noise in the muffler, i thought the muffler insides had separated from the muffler itself, hence Phill using some screws to secure it
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Re: 2011 MX5 Mod Options and their impact on Roadworthiness
It's quite common knowledge that if you do get pulled up for a noisy exhaust in Melbourne you can be directed to get a check for emissions/ noise at the drivers expense. A sporty note without frightening the wild life is achievable on most cars without attracting an order to get it checked. Having said that it does not seem to be applied to Harley's.
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Re: 2011 MX5 Mod Options and their impact on Roadworthiness
Regie - thanks for clarity on the sound levels. I've been listening to videos on YouTube and it doesn't seem that loud, but that can be subjective!
Mr. Morlock - thanks for the Melbourne specific view. I am hoping putting the baffles in the gwr muffler dampens the sound enough to be tasteful not loud. I don't want to be in a situation where I'm extra cautious all the time avoiding revving the engine in gears 1-3 and having fun! Also even if it is loud I will eventually get used to it, then I'll lose judgement on being cautious, which is even worse a situation!
Is one allowed some notice (enough to swap headers) to get these emissions/noise tests and are they expensive?
Edit - found this http://www.epa.vic.gov.au/your-environm ... le-testers
Mr. Morlock - thanks for the Melbourne specific view. I am hoping putting the baffles in the gwr muffler dampens the sound enough to be tasteful not loud. I don't want to be in a situation where I'm extra cautious all the time avoiding revving the engine in gears 1-3 and having fun! Also even if it is loud I will eventually get used to it, then I'll lose judgement on being cautious, which is even worse a situation!
Is one allowed some notice (enough to swap headers) to get these emissions/noise tests and are they expensive?
Edit - found this http://www.epa.vic.gov.au/your-environm ... le-testers
- hks_kansei
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Re: 2011 MX5 Mod Options and their impact on Roadworthiness
jassi wrote:Is one allowed some notice (enough to swap headers) to get these emissions/noise tests and are they expensive?
Edit - found this http://www.epa.vic.gov.au/your-environm ... le-testers
There are a few different tests they can order, the most common being a noise test, and less common being an emissions test.
From memory, other people who have had to have a noise test have been given a week or two to get the test done. The cost for a noise test wasn't particularly high from memory, just annoying since it needs to be done at one of a few specific places.
The emissions test is the harder one, and I've heard so many conflicting stories I have no idea about cost etc.
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Re: 2011 MX5 Mod Options and their impact on Roadworthiness
hks_kansei wrote:jassi wrote:Is one allowed some notice (enough to swap headers) to get these emissions/noise tests and are they expensive?
Edit - found this http://www.epa.vic.gov.au/your-environm ... le-testers
The emissions test is the harder one, and I've heard so many conflicting stories I have no idea about cost etc.
The cost from the link i posted above is as follows
The noise test fee is $43.70 (inclusive of GST). This fee is charged by the tester for his services and is not refundable.
The emission control and noise test fee is $87.40 (inclusive of GST). If your vehicle fails and the same tester conducts the retest, the retest fee is $43.70 (inclusive of GST). This fee is charged by the tester for his services and is not refundable.
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Re: 2011 MX5 Mod Options and their impact on Roadworthiness
All - does anyone know from personal experience what the header and midpipe install would cost and how much time should it take. Any gotchas or things to make it easier? I'm reading through install instructions on goodwin forums to understand if any issues with fitting the header into rhd, but you guys may already know the tricks to make it easier ;-) I just want to be informed when I negotiate the install costs/time as well as be able to guide the the installer if needed. Thanks!
- Regie
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Re: 2011 MX5 Mod Options and their impact on Roadworthiness
Header install probably around 3 hrs. It took me a while longer on my first set but now I've done a few I could probably knock it out in about 90 mins.
Good tip is to remove the alternator or at least pivot it as far fwd as u can.
The mid pipe is a 5 minute change over. It will be removed to access the headers anyways.
Good tip is to remove the alternator or at least pivot it as far fwd as u can.
The mid pipe is a 5 minute change over. It will be removed to access the headers anyways.
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Re: 2011 MX5 Mod Options and their impact on Roadworthiness
thanks for the time estimate Regie! if its just 3 hours, i guess i could be around at the installer's and see how the install is done
yes the alternator tip is what i gathered from the gwr forums as well! it seems thats the key to a smooth install. Any tips on where you adjusted o2 sensor cables so they don't melt/burn by touching the exhaust pipes?

yes the alternator tip is what i gathered from the gwr forums as well! it seems thats the key to a smooth install. Any tips on where you adjusted o2 sensor cables so they don't melt/burn by touching the exhaust pipes?
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Re: 2011 MX5 Mod Options and their impact on Roadworthiness
You will need a block off plate for the exhaust thingie from the stock headers to the inlet manifold as well, very easy to fabricate, just reuse the steel gasket .
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Re: 2011 MX5 Mod Options and their impact on Roadworthiness
Hey MLR - thanks for the response. Is there another term for the block off plate? Couldn't see it mentioned on the gwr install instructions http://www.mazdatalkforum.com/viewtopic ... 0b0cbc460f
The instructions do say to reuse the gaskets on the either sides of the header - is this what you are referring to?
The instructions do say to reuse the gaskets on the either sides of the header - is this what you are referring to?
The factory gasket for the header connection is reused. The factory gasket for the downstream connection is also reused...just use a very thin edge (such as on a small flat tipped screw driver) to GENTLY pry it off the factory header as shown and then slide it onto your new header.
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Re: 2011 MX5 Mod Options and their impact on Roadworthiness
MLR wrote:You will need a block off plate for the exhaust thingie from the stock headers to the inlet manifold as well, very easy to fabricate, just reuse the steel gasket .
no you don't

There is no recirc pipe on the NC's
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Re: 2011 MX5 Mod Options and their impact on Roadworthiness
Sorry about the incorrect information mate, for. Some reason I though NB.
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