RoadsterSport Helmholtz MX5 Midpipe with Converter - Suits NC Models - GR-031

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  • $899.00
  • Regular price $999.00
  • incl. GST

Unique Helmholtz MX5 Resonator is the Ultimate DRONE Prevention!

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A revolution in exhaust technology finally in a MX5 application, this mid-pipe features an exclusive Helmholtz Resonator that massively reduces the standing wave 'boominess' inside the exhaust system BEFORE it gets to your muffler of choice! Cuts the 'booming' frequencies of 120-130hz by 48+db inside a top up MX5 cabin which is a common source of complaints with aftermarket exhausts on the MX5.

We outfitted our Project 2012 PRHT MX5 with a computer and sound spectrum analyser and microphones and drove it under varying conditions and loads with mufflers and without any muffler to measure the frequencies coming out the mid-pipe. We then use that data and some special software to calculate the particulars of the Helmholtz chamber needed to precisely knock down the frequencies we do not want to hear while allowing the good throaty burble sounds to pass through. The result is an almost exotic burble throaty result, without the drone! Note it is very dual personality because the effect of the Helmholtz is very frequency specific such that under deceleration it is mild and quiet, yet when you push hard toward redline it sounds exotic and race-like. With the top down lots of throaty burble, but dramatically more tame when the top is up.

Designed as a bolt-on replacement for the factory mid-pipe to carry higher flow all the way out any of our mufflers. Works with ANY of our muffler choices and customers report great results with everything from our RoadsterSport line to the original MazdaSpeed Mufflers. Simple Bolt on.

INCLUDES TWO O2 SENSOR CONNECTIONS which gives YOU the option to later add our RoadsterSport headers and avoid engine codes (by using our O2 plug and play extension cords to relocate the factory O2 sensors to before and after the converter in this mid-pipe).

All stainless steel construction for years of driving pleasure. This MX5 MX5 mid-pipe is larger diameter than stock for superior flow, particularly when matched to our headers. This mid-pipe will raise the final sound level because of the higher flow larger diameter tubing and because the Helmholtz is frequency specific in operation.

BRIAN'S APPLICATION NOTES: It's a serious revolution in MX5 exhausts, makes just about any muffler combination MUCH more exciting. I never seriously considered less than our RoadsterSport SuperQ as appropriate for the NC Generation MX5 AFTER adding any header but this mid-pipe makes ALL our choices MUCH more exciting, particularly after header install. NONETHELESS, this mid-pipe is NOT for the timid. Why? Because the nature of this style of resonator is that the targeted frequencies are much LOWER volume and other frequencies not targeted are much LOUDER than with our standard mid-pipe. This dual nature of the performance means when you are hard on the throttle it is LOUDER than with our standard mid-pipe, but on deceleration or running in the low rpm ranges where these cars tend to drone this setup is much quieter than our standard mid-pipe. You get all the sweet sounds, without the drone.

A little on the science, we targeted 120-130 hertz range which is where most folks report uncomfortable 'drone' or 'boominess' and got a total of 48 decibel max drop right at the 125 hertz level...which is a MASSIVE reduction. Nonetheless, looking at broader range we get an average 20 decibel drop from 115 to 138 hertz with reasonable 8 decibel drop in the ranges of 95 to 115 and 138 to 180 hertz.

FREIGHT & SHIPPING NOTE: Due to the size of the mid-pipe box delivery can only be made to non residential addresses. Please email after placing your order and we'll work with you to find the best delivery solution.

Video Sample:

Shot on our Project 2012 with our RoadsterSport Street Header, RoadsterSport Helmholtz Midpipe, RoadsterSport SuperQ Exhaust. In this first sample notice what you do NOT hear, I get on it briefly and then engine brake almost down to a stop and during that engine braking the system gets more and more quiet where normal systems would drone as you engine brake down through 3000 rpms to 2000 rpms.

Second Video Sample: Shot from the bumper this clip massively exaggerates the volume but notice again what you don't hear, lots or racy sound when on throttle but every time I close throttle it quickly gets quiet instead of drone like many systems.


And now a more complete driving sample with camera in the driver's space: