Aftermarket Headers NB

[philz]

thanks PC for the updates and dyno figures.

10kw sounds great, but I would assume engine response will now be fantastic.

Would love to see the dyno charts for stock vs mods, the power and torque curves.

[stevesports]

iirc, the headers for the NB8B are quite well designed compared to the NB8A ones, so i guess a cheap alternative is to source from the wreckers a second hand set of NB8B headers.

[pcmx5]

Actually the NB8A's one are very well designed compared to the NA8A ones and i am pretty sure that a lot of the gain in this case came from the catback.I went from 66.8(Genie SS catback) to 71.2 T&C with no further mods,

I have no idea if NB8B' stock headers are better than NB8A's.


Peter

[stevesports]

i just heard from the miata.net forums that a common cheap upgrade for the NB8A is to swap the NB8B headers into it.

[Okibi]

I'm pretty sure the NB8A came out with a cast manifold in the US of A and thus it's very easy to look at their websites and see massive improvements made by after market extractors.

[pcmx5]

i just heard from the miata.net forums that a common cheap upgrade for the NB8A is to swap the NB8B headers into it.

Not saying you are wrong Steve, but the headers on the NB8A here almost look like aftermarket whereas my NA8A had a cast job.

Maybe Okibi is right and the stock US ones were not the same as here and THEY do get a huge improvement
fitting aftermarket ones.

Has anyone compared Aus. NB 8A/NB8B stock headers?

Peter

[pcmx5]

Philz,

Any chance of you putting the Dyno sheet up for me? I am computer challenged!!

Peter

[stevesports]

i just heard from the miata.net forums that a common cheap upgrade for the NB8A is to swap the NB8B headers into it.

Not saying you are wrong Steve, but the headers on the NB8A here almost look like aftermarket whereas my NA8A had a cast job.

Maybe Okibi is right and the stock US ones were not the same as here and THEY do get a huge improvement
fitting aftermarket ones.

Has anyone compared Aus. NB 8A/NB8B stock headers?

Peter

yeah i assumed the NB8A in the states are the same as the ones here in terms of headers. However, it wouldn't be the first time that the US MX5's are different to Aus MX'5.

example would be NB8B brakes. They have the standard ones, and the sport ones. We have only 1 type, which is equivalent to their sport type.

[philz]

I've uploaded the dyno that PC sent me. Thanks Peter!



And looks like it's much more linear, a healthy bump at 2000-2400rpm.

Edit:
I've read about changing the exhaust manifold from the NB8B, from CAST to Tubular style.

Though there are some US miatas that differ from the AUS, due to California's strict emission laws- CARB.

[Okibi]

The JDM NB8A headers are the same except they don't have EGR.

[Alex]

RE: NB8A US vs AUS

The NB8A US headers were cast as it was a cheap way to make sure they cleared the steering column on left hand drive cars. A redesign of the headers meant that the NB8B headers were tubular and better flowing.

AUS NB8A headers should be tubular along with the Jap spec models, the NB8B headers are also tubular but I'm unsure if they changed the design or not.

[Leonw]

I've uploaded the dyno that PC sent me. Thanks Peter!



And looks like it's much more linear, a healthy bump at 2000-2400rpm.

Edit:
I've read about changing the exhaust manifold from the NB8B, from CAST to Tubular style.

Though there are some US miatas that differ from the AUS, due to California's strict emission laws- CARB.

Just to add to the fitting of the exhaust organised by Peter in Geelong - we drove down from the Central Coast to have the work done and drive the Great Ocean Road in December.

The trip was awesome. We did just under 2,500ks in 5 and a half days. The car went and now goes like a bullet with Peter's exhaust, plus it sounds terrific. We averaged 40.34 mpg for the trip. Don't know what that is in litres per hundred.

We are looking forward to going down to Vic again to do a bit more sight seeing when the weather gets cooler.

Leon

[crzymx]

This is interesting, so a few questions.

Without any exhaust upgrades, the headers will make close to no difference. Why is this?

Why would headers be the last thing done to gain the last bits of power out of the engine?

What kind of noticable difference do you get from a catback (hi flow cat and new midpipe)? Is there a lot of noise that comes out of it, im scared it will get annoying after a while..

[philz]

The header MIGHT make a difference, but you will still be restricting power with the stock cat, midpipe and muffler.

So it's better to free up everything. Why use only 50% of the headers potential...

[pcmx5]

This is interesting, so a few questions.

What kind of noticable difference do you get from a catback (hi flow cat and new midpipe)? Is there a lot of noise that comes out of it, im scared it will get annoying after a while..

I think that I can be confident based on my results and Leon's that a Town and Country catback on an NA8A and NB8A will add about5- 6KW on average.a high flow cat may add a little more.

The issue of noise is subjective but it has a nice note when asked for a bit of effort and is quiet at normal cruising speeds. In fact Chris H's setup on his NB8B sounds magnificent but he would actually like a bit more noise(and no he is not a hoon).I spent (wasted) a lot of money trying to achieve that result.I have no idea why this set up works and we arrived at it by trial and error ,but it does work.

I have changed my cat from a highflow to a high flow steel cat that is smaller and had to add a bigger reasonator as the new cat made the exhaust a lot louder.I haven't put the changed system on the dyno.

Peter