Charlie Brown wrote:Best bang for your buck is without doubt
a set of headers. And yes dyno’s are not the be all and end all but my car registered 91.6rwkW standard and 105rwkW with the headers. Cost is about $555 landed, snail mail from Goodwin Racing.
http://www.good-win-racing.com/Mazda-Pe ... haust.htmlCold air intakes for the NC, in my opinion, are a waste of money. The standard intake sits horizontally in the nose of the NC and takes in cold air without modification.
I have a Cobalt CAI fitted, cost was about $140 delivered including filter when I got mine it’s slightly dearer now.
http://www.miatamania.com/Shop/ViewProd ... exID=73664The Cobalt CAI is the same length as the stock intake but sits vertically with the intake behind the lower slot in the nose. The K& N panel filter has the advantage that you can wash it clean, which you do often as the CAI picks up sand and bugs easily.
I noticed no difference when I fitted the CAI and there is no additional intake noise. The AEM / Mazdaspeed (about $360 landed, snail mail from Goodwin Racing) sits diagonally across the nose, its longer than standard and may have a minimal increase in torque at lower revs. Chris has dynoed a number of different CAI’s on his race NC’s and only picked up 1kW.
Mufflers. A word of warning. If you fit headers there is only one muffler to get and that’s the Goodwin ‘Q’ (cost $836). Any other will be way too loud. I’ve tried 5zigen, and the Roadstersport with baffles in and both will have you defected and your neighbours chasing you down the street trying to do you some injury.
Also besides the overwhelming loud note you have drone which kills the pleasure of driving even with a loud exhaust note. I think the note the stock muffler gives with the headers is fine, the main reason I wanted to change was a decrease in weight which would eliminate me having to swap mufflers at the track.
Performance wise Goodwin has some figures on his site about the development of the mufflers which is a good read. If you believe the figures you look at about a 4rwkW gain. A
new mid pipe (cost $643) around another 2 rwkW.
So summarising a set of headers for $555 will get you around 13rwkW.
Add an AEM intake, a mid pipe and a Q muffler for $1839 and you get another 7rwkW. Pretty easy to see where you need to spend your money.
