Two Years On
May 2010 marks 2 years with the NC.
So naturally, I had to mark the occasion with a suitable edition.
Namely a much needed exhaust upgrade: the HKS Legamax Premium.
That's the stock muffler on the left, HKS item on the right.
There has been a great deal of deliberation by yours truly over muffler selection for the NC.
I started this thread on MX5 Cartalk to assist with my research.
Primarily, the NC owner is faced with the question - stay with the dual muffler, or go single.
The benefits of the single muffler are obvious - free'er flowing, cheaper, and much lighter.
Greddy offer one, as does Goodwin Racing. Custom is also an option of course.
However as the numerous threads, and Brian Goodwin's tireless development has shown,
the 2L MZR engine in the NC LOVES to drone. It's also a fairly loud engine,
with some full exhaust setups seeing 90db at track days.
So any exhaust mods for a road going NC have to be treated with caution.
Initially, I was going to go with a single muffler. However, after much consideration,
and countless threads and You Tube videos, I had to conclude that sound
was more important than weight or horsepower. With a road car, I reason that max HP isn't
something I'm going to use all the time. However sound is something that is always there.
What's more, for a daily dríven car, it's a big part of the Roadster experience. So it's important to get it right.
There aren't many aftermarket exhausts getting around on NC's yet, so first person experiences were scarce.
I'd heard the Mazdaspeed muffler in person, and was not impressed. Plus the car had an aftermarket midpipe.
Lots of drone at constant throttle.
Meanwhile, I kept coming back to this video (and the one on the HKS website)
So, as some will know, a small band of us crossed the border into VIC in March
to rescue one of the greatest NA8's known to man-kind!
That car now belongs to Reggie, and the epic story of it's retrieval can be read on the Roadsterlife blog.
However, while in VIC I also met up with Andrew to purchase this exhaust.
The muffler install was straight forward, it's just a diff back muffler.
Just a few bolts to undo, and there is a replacement gasket provided in the kit also.
First drawback - stock muffler, 11kg, HKS Legamax: 12.5kg
Looks quite cool though. Sits lower than the stock item, so you can see the twin cannisters.
Soundwise, it's exactly what I am after.
Firstly when you turn the car over, you notice a bit more exhaust sound, and a much lower tone.
On the freeway, at constant throttle, I would say it's maybe 5% louder than stock.
Under load it's probably 15-20% louder.
It has a nice low hum up to 3000rpm, the note hardens, and above 4500rpm it develops a bit of a rasp.
Brian Goodwin has said a great deal about the drone the NC makes at 3000rpm on trailing throttle.
Well HKS seem to have pushed it further down - it get's some nice standing waves around 1500rpm.
Not the 'brown note' but close. Only at that rpm though, which is above idle and below cruising speed.
So you never notice it.
Driving impressions? Well, this is the good part.
Immediately, the 'seat-of-the-pants' dyno pointed to better response through almost the entire rev range.
Throttle response is improved again from when I added the Autoexe intake. In fact I would say it is now
where I have wanted it to be. Gear changes, and particularly rev matching, is that bit sweeter now.
Certainly, the sound has some impact on this. But it's no placebo effect.
Basically, I was hoping for better tone, more noise at wide open throttle, and some improved
throttle response. The improvement in pickup throughout the rev range has surprised me.
Sound is great, exactly what I wanted. All in all, a very worthwhile upgrade.
