New NC1 owner with exhaust questions

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VAMiataFan
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Joined: Mon Nov 24, 2014 5:55 pm

New NC1 owner with exhaust questions

Post by VAMiataFan »

Hi Guys,
I recently was lucky enough to purchase an 07 PRHT, GT with a 6 speed, only 13,000 miles and it is liquid silver.
This is my first NC, prior 2 Miatas were an NA and a NB. The NB, an 01 SE had RB headers, RS midpipe and RB dual outlet exhausts. I absolutely loved the sound. The car was a 3rd car and used only for sunny weather top down cruising.
Here is my question, I would opt for the same setup on my new NC were it not for all the discussion re: Brian's build of his 2010. As a side note, Brian, your street build has provided what I consider to be invaluable information to us newbies just starting with a similar car.
While my new ride will be again a 3rd car used primarily for top down cruising, I am somewhat concerned about both the noise level and the need (I guess) to use the catted header to be legal in Virginia.
I am thinking I should go with the exact setup Brian is using or using the catted street header, the factory midpipe and either the RS II exhaust or the Q. Having said that, I am looking for max HP gain from the exhaust.
I hate the thought of having two aftermarket cats on the car and potentially looking at replacement after 2 to 3 years.
I am just looking for more low and mid range power and aggressive sound while keeping it legal. This car will be for street use only. What combination will be the best or is there another setup that you guys would recommend?
I do plan or adding the Progress springs and RB sway parts as step two to address the "SUV' look.
Thanks for any and all help.

Rich
Brian
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Re: New NC1 owner with exhaust questions

Post by Brian »

Hi Rich

Welcome. Glad you like our 2012 Project PRHT, my wife loves that car and doing that project has helped me understand the needs of a big group of non-racing enthusiasts that want more fun than stock...without making it too loud, too harsh, etc.

Indeed the max hp result would come with using our Max Power header with no cat...and that would not be legal in many states. Our Street header is massively better than the stock header but won't capture as much gain as the no cat version...and will not add as much sound. For both choices the exhaust note is going to be more aggressive...and the most mellow muffler choice to match with the header change is our SuperQ. Both my car with max power header and 2.5 conversion, and my wife's 2012 PRHT project car, run the SuperQ these days....it's our best match for controlling the sound unleashed from any header upgrade. As for whether you go Street header combo with that SuperQ... or Max Power Combo with that SuperQ...it comes back to how aggressive you want the results. If you want to keep it a mellow cruiser, likely the combo with the street header and SuperQ is your best choice....which is linked HERE.
Brian Goodwin
Good-Win Racing
www.good-win-racing.com
VAMiataFan
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Re: New NC1 owner with exhaust questions

Post by VAMiataFan »

Thanks for the input, Brian. I had really hoped to get more feedback from other users with their thoughts on various header and muffler combinations, but as I am anxious to get some better sound than stock I have gone ahead and ordered your RS II with the straight tips that is on sale.

This is a start and will allow me to judge the increased sound from this change only. I still expect to be ordering the street header shortly, but would still like to get any advice from other users.

How about it guys..........

Thanks.
Rich
Chuck H
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Re: New NC1 owner with exhaust questions

Post by Chuck H »

Brian has lots of sound clips of his various offerings linked in the exhaust section that should give you a pretty good idea of sound. You can also go over to Miata.net and do some searching and you'll find 20,000 threads on mufflers and which ones sound the best. The only thing you wont find over there is any consensus, since everyone has their own particular taste and tolerance for noise. :wink: You will find that Brian's Roadstersport options are very popular over there, though. They're very high quality, and priced very reasonably compared to some of the other options out there. Compare something like a Borla muffler to the Q, and you'll be shocked at the difference. And the much cheaper Q is higher quality!

If you are really looking to maximize power, a completely cat-less setup will give you the biggest gains, but of course be illegal in all 50 states (and kind of smelly, too). There's just no way of getting around the fact that cats always add some small amount of restriction to the exhaust, and that putting one in the header requires the primaries to be shorter than ideal for max power. A longer-tube cat-less header with a catted mid-pipe is going to be the next best option when it comes to maximum power. The Roadstersport Max Power header has been the champ for making power in any back-to-back testing so far. The newest PPE long-tube header hasn't actually been tested on a 2.0L motor yet, but it should give the Max Power a pretty good run for its money. The downside is that the PPE header itself isn't stainless, even though it's ceramic coated, and it's quite a bit trickier to install. The Roadstersport catted header is also a big improvement over the OEM one, but will give up a little bit of power vs. the longer-primary catless options. But it's easier to install, and more likely to get you past the smog police.

As far as mufflers go, most of the difference is in sound. They all flow better than the OEM one, and will make a little more power. Straight through mufflers like the Roadstersport Race Single and Street Single have the lowest restriction, will make the most power, and will be the loudest. Dual outlet mufflers like the Roadstersport II, Q, and Super-Q may give up 1 or 2 hp vs. the straight-through options, but they're significantly quieter.

If you have the budget available, and you're definitely changing out the header, then a tune is where you will really see the nice power gains. Headers increase the exhaust flow enough that the factory tune doesn't have enough self-adjustment range to maximize their effect. You will be perfectly safe running the factory tune with an aftermarket header and will see some nice gains, but there's even more power available just waiting to be un-locked with a more aggressive tune.
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VAMiataFan
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Re: New NC1 owner with exhaust questions

Post by VAMiataFan »

Thanks for the reply, Chuck, you reinforce a lot of the points made by Brian. I will surf the threads on Miata.com to get some other views as well.
I am definitely going to move ahead with some header option for for the increased power and also to add some better sounds.
One question, I would love to use the Max Power Catless header rather than the more restrictive street header if I could be reasonable assured of not throwing codes. Would the RS midpipe with cat help to avoid codes or would sticking with the factory mid pipe be a better option?
Do any of you guys have either of these set ups? If so, what about throwing codes and how much louder with the header, RS mid pipe and RS II?

I know, a lot of questions but I would like to get this right the first time so I would greatly appreciate any other thoughts.
elloco54
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Re: New NC1 owner with exhaust questions

Post by elloco54 »

Save yourself a lot of headaches and go with the max power complete combo. Easy install, sounds great pleasant at freeway speeds, no engine codes and includes everything you need. Combine that with a Motoeast tune and it becomes a completely different car (as in way more fun) :lol:
VAMiataFan
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Re: New NC1 owner with exhaust questions

Post by VAMiataFan »

Thanks for your input, elloco 54.
By "the max power complete combo", I assume you mean the Max Power header (without cat), the RS midpipe and RS exhaust (I have the RS II on order).
I am sure the power and sound of this set up would be great, but do you have this setup on an NC and have you avoided throwing codes due to not having the cat in the header?
Also, I live in Virginia and am not sure what problems, maybe none, I would run into with annual safety inspections. To the best of my knowledge, Virginia doesn't perform emissions testing in the Richmond area, they only test in Northern Virginia in the DC suburbs. If anyone can confirm that I would like to hear from you.

I will also do a local check with an emissions center in my area

elloco 54, hope this works out I would love to have the max power rather then the street header...............more power, ,more sound and one less cat to worry about replacing in the future.
Chuck H
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Re: New NC1 owner with exhaust questions

Post by Chuck H »

Just one minor note to add. I think you're worrying too much about having to replace cats on the car, whether the original ones or aftermarket. OEM catalytic converters are warrantied for 80,000 miles and the manufacturer will replace them for free if they fail in less time than that. The aftermarket ones don't carry the same warranty, but they should all be good for 80,000 to 100,000 miles of normal use. The only thing that's going to burn them out quicker is running super-rich, or with superheated exhaust from a supercharger or turbo.
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StephenW571
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Re: New NC1 owner with exhaust questions

Post by StephenW571 »

I agree with Chuck H
I put the catted street header, catted mid pipe and Q muffler on my 2011 prht about a year ago.
No propblems what so ever. Great increase in power/torque and sounds really good too. I left the baffles in the muffler off as this suited me better for the sound i wanted.
No need to re-flash the ECU either, the car adapted very nicely all by itself. No codes what so ever either. Brian says most will self adapt very well but a few will not.
I asked Brian on the benefits of an ECU reflash, and short answer is, no real gain in power but would remove the second gear hesitation. I can live with the latter and i now know exactly where this point is in the rev range so i just drive it accordingly.

I went through the same concerns and thoughts you seem to be doing right now.
My advice, dont worry too much, study the threads well to get yourself comfortable and then just go do it, you wont regret it.

Happy holidays
Steve W
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Re: New NC1 owner with exhaust questions

Post by skeeler »

VAMiataFan wrote:Hi Guys,
I recently was lucky enough to purchase an 07 PRHT, GT with a 6 speed, only 13,000 miles and it is liquid silver.
A minor correction: Liquid Silver is a 2009-2015 color. A silver 2007 has to be Sunlight Silver.
2009, STR & DD. 1995, HPDE. 2004 MSM, sold. 2010 Mazda3, hers.
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