2003 Induction Upgrades

[gregatchison]

Brian,

I purchased a Roadster Sport 3 muffler last year for my 2003 LS and absolutely love it! As anal as I am, I even polish the muffler after almost every wash.

I'm considering the notion of upgrading my intake and considering your MonsterFlow with the cool box. Are there any limitations, as I have Cruise Control and ABS? Is there any difference in performance between the polished and carbon fiber?

Finally, I'd like to upgrade my suspension sometime. I have the sport suspension, LSD, and ABS and wonder what you might recommend. I'm not looking for a "race car rough" ride, but would like greater corner holding and would like a lower ride heigth.

I look forward to hearing from you or anyone with similar experiences.

Thanks,

Greg

[Brian]

Hi Greg,

Thanks for the kudos on the RoadsterSport Exhaust. On the intake side, the MonsterFlow intake and CoolBox fits with all factory parts on 99-05 Miatas including the ABS and tower brace, cruise, etc. No difference in performance between the carbon or aluminum versions.

On suspension, it all depends on how racy you want the result. Assuming your intended purpose remains purely street then my suggestion is either Racing Beat "street" springs with Koni sport shocks or Bilstein PSS coilovers.

First, the RB springs and KONI shock combo. The Racing Beat springs will lower your Miata just about an inch and the Koni shocks will give you control over damping such that you can turn them soft for around town or crank them up stiffer for days in the twisties. At the soft setting the ride quality of the Koni and RB springs combo is at least as good as your present factory sports suspension and yet handling will be a nice step up in control.

Second, the Bilstein PSS is designed by Bilstein as their ultimate street setup and though it does not have the adjustable damping of the RB spring and KONI combo it is a threaded body coilover and that means you can set the height to precisely what YOU want. You can go down an inch and decide later to go a little more. Or, if you go down an inch and decide later that you want to raise it back up a quarter of an inch then this setup gives you that control. The damping is matched to the progressive spring rates for a ride that is at least as good as you have now but with more control and much less dive and squat.

[Greg Atchison]

Brian,

Thanks for the quick response. I appreciate your condor and recommendations.

While you addressed the shocks and springs, I just want to confirm that I'd be better swapping out my factory sport shocks (Bilstein) for the Koni's. In addition, you did not mention anything about upgrading the sway bars. Would I be better off ordering the RB package (springs and sway bars), along with the Koni shocks?

If so, should I upgrade the mounts for street driving, or is that reserved for autocross and track driving?

Thanks,

Greg

[Brian]

I didn't suggest the sways yet because you mentioned you wanted to lower the car but didn't want a racy car ride. Thus, my suggestion is to start with the shocks and springs and see what you think of the result. The lowering by itself will mean the factory sways don't need to work as hard to keep lean under control and the higher rate springs will further reduce lean. You might find you have what you want after the shocks and springs. But if the body lean is still too much after those changes for your tastes then indeed the sways would be the next step.


On the Koni v. Bilstein, I like to go to an adjustable shock so we can tune the ride to the higher rate lowering spring...and user preference. Also, again you mentioned you didn't want a racy ride and the Bilsteins are already pretty stiff valving and with the higher rate springs under consideration the ride would get stiffer. But with the Koni and RB spring combo you will get the lowering and handling and yet a ride quality equal to or better than you have with the Bilsteins.

[gregatchison]

Brian,

I got my MonsterFlow intake and CoolBox about 2:00 pm on Friday afternoon. After mowing the yard, I had the intake and CoolBox installed in just over an hour.

It went together really well. The only suggestion I'd have might be to put a little more bend in the Airflow Meter side of the intake so that it better aligns with the Cool Box.

While I like the power boost above 4,000, it is a little loud and drowns out the sound of my Roadster Sport exhaust.

Thanks again,

Greg