RoadsterSport 4 Helmholtz Polished Stainless Steel Miata Exhaust Muffler for Miata 1999-2005
Images may differ from actual product appearance.

RoadsterSport 4 Helmholtz Polished Stainless Steel Miata Exhaust Muffler




Price: $399.00



Free shipping offers apply only to destinations within US Lower 48.

Price: $399.00



Free shipping offers apply only to destinations within US Lower 48.


FOURTH GENERATION UPDATE....The Helmholtz chamber revolution in exhaust technology finally available for all Miatas! Our new HELMHOLTZ exhaust system features an exclusive Helmholtz main chamber that massively reduces the standing wave 'boominess' or drone inside the exhaust system! Cuts the 'booming' frequencies of 120-130hz by over 35+db inside a top up Miata cabin which is a common source of complaints with aftermarket exhausts on the Miata. Result is all the FUN throaty sounds you want, without the drone other systems make that wears you out on long uphill and downhill sections of road.

Updated version of our favorite NB Muffler, now the ONLY choice on the market with Helmholtz chamber...AND adjustable sound level! YES, fits manual and automatic transmission. Built in solid 304 stainless steel and completely polished to a mirror finish, this high quality Miata exhaust is our only choice that incorporates a baffle insert that gives YOU some control over the final sound level (baffle in is only about 15% more sound than stock, baffle out is about 25% more sound than you always have a choice for those longer trips). Weight is lighter than factory, 18.25 pounds.

For those that want even more sound add our highflow Miata midpipe for more flow and another 10% more sound.

This latest version of our best selling Miata exhaust has both baffle included and a double walled tip for years of lasting good looks while giving you control over the final sound level. And, you always have the option of our packed baffles which are sold here separately.

BRIAN'S APPLICATION NOTES: This is an AGGRESSIVE exhaust at full throttle! The helmholtz addition does not make it quiet, quite the opposite, it allows almost a straight pipe full flow design with good control over drone when just cruising so we can let all the fun sounds out at full throttle. The Helmholtz chamber knocks down what most of us perceive as drone by over 35 db but it lets all the rest of the upper frequency fun and pops and burbles right on through! That means by definition this muffler is aggressive, has a ton of attitude on an otherwise stock Miata, and is NOT for everyone! Given that this muffler is aggressive on otherwise stock Miata, it will be really loud, race track loud, if you add header and highflow cat. Designed for the three pedal owners out there who love to zing these amazing sportscars to redline daily. Know who YOU are, if you are actually driving the car around at very low rpms our experience is that you will prefer the mildest bigger mufflers such as our Racing Beat, and in our experience this includes all owners of the optional automatic transmission, and any other owners who drive around at low rpms most of the time. If you hit the redline at least three times on the way to work in your Miata, this might be your exhaust. If you never hit the redline because you are afraid you will 'hurt' the car, please look at our Racing Beat exhausts

LIFETIME WARRANTY, this Miata muffler is made with pride in the USA. YES, includes gasket and hardware needed for install.



Customer Reviews

RoadsterSport 4 Helmholtz Polished Stainless Steel Miata Exhaust Muffler

Great fitment, car sounds amazing with the new exhaust. I have no engine or exhaust modifications besides the muffler and it sounds great with or without the baffle. Almost no drone in the cabin even with the hardtop (notice a little under load going uphill around 3k rpm, but none while cruising). Highly recommend if you're on the fence about it!

Great way to make friends!

On my inaugural spin around the neighborhood some people out for a walk flagged me down! I stopped and they were like "hey, weren't you at the racetrack Friday?" I told them yes, and I was worried they were gonna yell at me about my loud exhaust. Anyway, they agreed it sounded good and I found some local gearheads.

This exhaust IS fairly loud at higher RPMs. At low speed and idle it's just a deep hum. However, if you're putting this on a stock NB you know you need those RPMs. Makes some nice pops and burbles occasionally on decel.

If you are in anyway on the fence on this product, do yourself a favor and just get it. Love the sound, it is not at all too loud for my taste. My opinion is that a little louder the better in a sports car that sometimes barely comes up to the lug nuts of other vehicles...
It actually took me longer to remove the old unit than it did to install this. I highly suggest the red polyurethane hangers. I used liberal sprays of white lithium grease.
It's a quality product and I am once again 100% satisfied.

When I was on the hunt for a new exhaust it was extremely difficult for me to decide what options to pursue for a variety of reasons. Video footage of exhausts can never really compare to hearing it in person and everyone has different tastes. What may be loud and obnoxious to one person might be quiet to another.

With all that said, It's been almost a year ever since I've installed the Roadstersport 4 and it has been everything I have ever wanted. The way I see it, this exhaust enhances the sound of the car instead of trying to change it. It produces a confident and deeper tone with subtle burbles and the occasional pop. It is reserved enough to be comfortable but can be playful when you want it to be. Run it without the baffle.

Addicted to the gurgles and pops with top down, baffle out. Deep tone down low with nice growl when you step on it, more noticeable in lower to mid RPM range. Baffle is perfect for the longer drives and easy enough to add/remove. Fantastic exhaust.

This exhaust is amazing. I just love the sound it makes when you are driving top down and accelerating. I love how it has a low rumble/growl sound before you accelerate. I am happy with the purchase of it.

Delivered in 5 days. Very good quality. 45min install.
Excellent sound!!

Beautiful muffler and sounds awesome. I am running with baffle in. I have not stopped smiling since install.

So happy with this purchase! Very easy to install, took me about 30 minutes in total and the sound is perfect! Not very noticeable change on idle, but perfect mellow tones when on throttle without any booming or drone. I will definitely be buying the midpipe in the future to complete the system.

Want to Review This Product?
(You must be logged in as a Good-Win-Racing Member. Join Now. It's Free!)