NB8A Exhaust Compatible with NA8

myredmx5 · Postby **myredmx5** » Wed Aug 01, 2012 1:08 pm

QUESTION??

I have an NB8A complete exhaust system (manifold to exhaust chrome tip), will this fit on my NA8 or are some modifications necessary.

zossy1 · Postby **zossy1** » Wed Aug 01, 2012 1:17 pm

Bloody good question.

Obviously the individual parts are not compatible with each other but a full system front-to-rear... not sure.

I have never tried it myself, but in theory the routing should be fine. The problem I can see is that the mounting bars for the rubber pipe hangers may not be in the same spot and may need to be cut off and relocated...? Just guessing but that is one potential problem I can foresee.

Another potential issue, and this would affect routing, is the bracing between NA8 and NB8A. I can't recall the differences off the top of my head, I think it is mostly the same and there was only MORE bracing as time went on so it might not be an issue. Potential issues are more likely in the rear subframe area I think.

hks_kansei · Postby **hks_kansei** » Wed Aug 01, 2012 1:27 pm

Headers will fit, but the EGR fitting will be different (I'm not certain on what the difference is though)

Exhaust hangers will likely be in different places.

And as mentioned, there might be an issue around the rear subframe.

While there was bracing between the rear lower control arm's rear bolts on both NA8 and NB8A, the bracing was slightly different, the NA8 brace bolted to the alignment bolts and bent up slightly between the 2 control arms.
The NB brace was simply a flat tube bolted below the alignment bolts (Mazda added captive nuts here for this)

It's possible the exhaust may hit the NA brace.

zossy1 · Postby **zossy1** » Wed Aug 01, 2012 3:08 pm

Ahh yes, EGR. My NA8 (1994) did not have any EGR, not sure about the 1995-97 cars that had OBDII.

So that is one thing you WILL need to do, find a bung for the EGR fitting on the NB8A header - at least for early NA8s (can't speak for the later cars).

hks_kansei · Postby **hks_kansei** » Wed Aug 01, 2012 3:12 pm

zossy1 wrote:not sure about the 1995-97 cars that had OBDII.

???

ODBII came in with the NB8B in 2001 or so. (For Aussie ones)

It was only the USA who got it earlier to my knowledge. (I think 1998 they got it?)

zossy1 · Postby **zossy1** » Wed Aug 01, 2012 3:15 pm

hks_kansei wrote:
zossy1 wrote:not sure about the 1995-97 cars that had OBDII.

???

ODBII came in with the NB8B in 2001 or so. (For Aussie ones)

It was only the USA who got it earlier to my knowledge. (I think 1998 they got it?)

I'm sure you're right - once again my US Miata background leads me astray

Well in that case, you will definitely need a bung.

OBDII was mandatory on all vehicles in the USA from 1995 onwards. This is why all NA8s worldwide had an ECU change in 1995.

sailaholic · Postby **sailaholic** » Wed Aug 01, 2012 11:49 pm

Having recently fitted a aftermarket nb extractors I can say the do fit.... But it doesn't line up at all well with the name cat back. Nb are too short with the wrong angle on Them.

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