300,000 mile NA6 smog check saga

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GPZrider
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300,000 mile NA6 smog check saga

Postby GPZrider » Sun May 26, 2013 10:19 pm

Well, I don't post actively here anymore. But, I still have my NA6 and drive it everyday.
I just got the car smogged recently, and thought this might help some people who are having trouble with smog check.

About the car
1992 NA6, at the moment of passing smog check it had 296,993 miles.
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Things related to smog check

Original engine, retain stock air cleaner box set up.
Jackson Racing (carb legal) header ( due to the exhaust leak from original exhaust manifold)
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Flyin Miata Hi-flow cat
Racing Beat cat back exhaust

Okay, so what do I need to do in order to pass the smog check with 21-year old car (with nearly 300,000 miles on it)?

Let's the show begin.

1)Start from obvious things. (e.g. ; basic tune up)

change air filter
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Top : new one
Bottom : old one

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old one close up
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change spark plugs

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change spark plug wires

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change oil and oil filter

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2)The secret of passing ...

set the ignition timing back to stock (I normally run at 12° ).

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See the line and punch mark? Punch mark is 10°, the line is 12°.

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And the biggest secret is ...

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Mazda OEM cat.

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Compare to FM hi-flow cat that I normally use. It's twice as heavy ...

3)things may or may not help but I do anyway

Redline fuel system cleaner
Switching to Chevron premium gas (normally run on regular)

4) ... and it's been said over and over again,
completely WARM UP your car before taking test! It DOES make difference. If you have to wait at the smog check station, keep the engine running.

And the result is ...
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PASS! :banana:
(it may be a little bit hard to read. The results are
HC

15MPH 40(ppm) (Max allowed 94)
25MPH 12(ppm) (Max allowed 76)

CO
15MPH 0,02% (Max allowed 0.58%)
25MPH 0.01% (Max allowed 0.49%)

NOx
15MPH 0 ppm (Max allowed 847ppm)
25MPH 0 ppm (Max allowed 786 ppm)
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MartinezA92
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Re: 300,000 mile NA6 smog check saga

Postby MartinezA92 » Mon May 27, 2013 10:25 pm

God damn those are clean numbers. I do smogs at a dealer on mostly new cars and the numbers are similar.
92 Miata/1.8 - 6speed/3.90 - MS1 - 460s - 2860/v-bands/EWG
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w00fm00baaa
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Re: 300,000 mile NA6 smog check saga

Postby w00fm00baaa » Tue May 28, 2013 3:27 am

Holy crap 0 NOx
i rike fassssssssssssssssssst
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Thriceeee
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Re: 300,000 mile NA6 smog check saga

Postby Thriceeee » Tue May 28, 2013 6:33 am

That's... impressive!!
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mrFanel
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Re: 300,000 mile NA6 smog check saga

Postby mrFanel » Fri May 31, 2013 10:00 pm

Those numbers are crazy impressive for a 300k motor! FYI - I managed to smog my 97' with the FM high flow cat - it BARELY passed, I mean I was on the borderline... but it passed!!!
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99nb
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Re: 300,000 mile NA6 smog check saga

Postby 99nb » Fri May 31, 2013 10:51 pm

GPZrider wrote:And the biggest secret is ...
Mazda OEM cat.


:)
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GPZrider
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Re: 300,000 mile NA6 smog check saga

Postby GPZrider » Thu Apr 30, 2015 3:39 pm

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OK, so 2 years later, and at 342, xxx miles, my NA6 is still running strong as my daily driver.
AND it’s time for smog check again.

Did all the usual thing (see my original post) and took it for a test this morning, and ...

IT PASSED !
(I’m away from home right now and can not post the scan of the print out, but it went like this.)

HC at 15MPH 34ppm (max allowed 94), at 25MPH 10 ppm (max allowed 78)
CO at 15MPH 0.06% (max allowed 0.58 ), at 25MPH 0.01% (max allowed 0.49)
NO at 15MPH 0 ppm (max allowed 847), at 25MPH 0 ppm (max allowed 786)

I’m in the pretty good mood despite the lack of enough sleeping time, having been working way too much.
At least my car and motorcycle are running great.
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2cam16
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Re: 300,000 mile NA6 smog check saga

Postby 2cam16 » Thu Apr 30, 2015 7:33 pm

Impressive! Congrats !
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Re: 300,000 mile NA6 smog check saga

Postby skoolboi » Fri May 01, 2015 12:01 pm

well done!
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rennkafer
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Re: 300,000 mile NA6 smog check saga

Postby rennkafer » Fri May 01, 2015 6:18 pm

That's impressive for a 300k+ engine. You would (not that you need to) get better numbers from regular than premium though. Being easier to ignite means it burns slightly cleaner.
Bill J
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Brain_zata
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Re: 300,000 mile NA6 smog check saga

Postby Brain_zata » Sat Jun 13, 2015 12:36 pm

342k running better than most everyones on here! loll
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Re: 300,000 mile NA6 smog check saga

Postby itsdrogbaaa » Sat Jun 13, 2015 8:54 pm

simply heroic

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