Advice on Exhaust please - Headers, cat, mid-pipe and muffle

[OzGuvnor]

I am looking to do the whole exhaust. Want to improve the sound and a little performance.

I was looking at Racing Beat Miata Header (from Good-Win Racing in US) http://www.good-win-racing.com/Mazda-Pe ... -1024.html

Plus the following:
* Cat-Back RoadsterSport 3 Miata Polished Stainless Steel Exhaust for 90-97
* RoadsterSport High Performance Miata Catalytic Converter-FEDERAL Version for 1994-1997

Has anyone fitted this to an NA8?

Outside that, what have you others installed and are either happy/unhappy with.

Cheers

[Magpie]

I have a Racing Beat header and full exhaust, no complaints. However consider a 100 cell CAT as this will be less restrictions. Plus be careful of running too rich as this will destroy the CAT and if it starts to melt you will cause an exhaust blockage. Yes experience.

[joshuam]

I have recently been looking into the Racing Beat headers and power pulse exhaust for my NB8B.

Shipping out of the states to Australia is VERY expensive, so my recommendation if you chose to get these products would be to buy the brand name headers and muffler, and get a local exhaust shop to make you up a custom mid pipe with cat. It will end up being mild steel instead of stainless for that section, but it will be cheaper than shipping bits those extra bits from the states.

With regards to the cat, 100 Cell is definately not emissions legal, but will get you the most flow without getting in big trouble with the EPA for completely removing it. I had 200 cell on my last car and I would do the same again for the MX5 (around 400 cell is usually stock).

[OzGuvnor]

So not understanding CAT's very well, is what you are saying that the less cells is better for performance - and that 400 is the stock part?

On the Racing Beat headers Brian Goodwin said he wasn't 100% sure of clearance regarding RHD cars. Sounds like you have fitted it without issue though. Which is positive.

Has anyone fitted heat shielding?
Looks ugly, but if it helps with performance... ?

[tbro]

pcmx5 where are you???????

Ozg your lucky as you live close to one of the best exhaust people around. Geelong mufflers ????? dunno.
Send a pm to Peter (pcmx5) and he'll be able to steer you in the right direction.


Terry

[hks_kansei]

Ozg your lucky as you live close to one of the best exhaust people around.

Also one of the worst.

Don't go to Exhaust Bros.

[joshuam]

So not understanding CAT's very well, is what you are saying that the less cells is better for performance - and that 400 is the stock part?

On the Racing Beat headers Brian Goodwin said he wasn't 100% sure of clearance regarding RHD cars. Sounds like you have fitted it without issue though. Which is positive.

Has anyone fitted heat shielding?
Looks ugly, but if it helps with performance... ?

A catalytic converter is made up of cells that do the actual work of cleaning up the gas emissions. Generally speaking, the more cells it has, the more effective it is at doing its job. HOWEVER, this also significantly reduces flow through your exhaust system. From a performance point of view, you want to remove it all together, but there are large fines in place for doing so (if the EPA are doing a sting with police a decat could result in a fine up to something around $7k). So it is a balance of effectiveness vs performance that you need to find for yourself.

I think 200 cell is the go-to for most exhaust shops when you just ask for a high flow cat. My last car was 400 standard, but I'm not sure about the MX5.

[Trackphotos]

I've got RB stainless 4-1 headers, magnaflow cat welded into RB connecting pipe, and an RB power pulse muffler. This is a clip recorded from a gopro mounted on the rollbar, using a $2 external mic: https://www.dropbox.com/s/lpog62025qh5l ... h.mp3?dl=0

Can't say I noticed any power improvement really, maybe a tiny bit but I expect it was more placebo than anything. The sound is nice, maybe a tiny little bit of droning around 3200rpm, but not a lot. It's louder than stock a fair amount, without being too loud to run at Lakeside, or drawing police attention as long as you're not booting it to redline. Overall pretty happy with it, being RB it was more expensive than a lot of other brands though. Still, happy.

[pcmx5]

Town and Country use a 200 cell cat and their exhaust,cat, reasonator, mild steel pipe and stainless straight through rear muffler is around $1000 fitted.It works well,makes more torque and power and sounds glorious.

Colin has done 4 in the last week or so.

I had a terrible experience at Exhaust Brothers(like HKS obviously) early in my MX ownership which lead me to T&C .Have done a fair bit of dyno testing on my car and plenty of others which show the gains in one case 12 RWKW,but a lot depends on the condition of the exhaust/cat being replaced with 6-8 RWKW being the norm.

My car is a little louder than the normal T&C set up as it makes 106 RWKW but there is a clip on T&C's Facebook page.

Peter.

[93_Clubman]

Got Garry Stewart full system for $1500 approx delivered from QLD (2005 prices: headers: $590 + hiflow cat: $370 + catback: $570).