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RoadsterSport Mid-pipe with Converter for 2016+ MX-5 Miata

MSRP: $918.85
Price: $799.00
You Save: $119.85 (13 %)
Item Number: GWR-RSMP-ND
Manufacturer: Good-Win-Racing
Manufacturer Part No: 61-2660
Good-win Racing Logo

Mid-pipe with Converter

Add more torque and a little more sound with our all stainless top of the line RoadsterSport All Stainless Midpipe!

Mazda gave us a serious challenge with the ND midpipe design but Good-win Racing got it figured out. Instead of the small ball/socket outlet of the stock midpipe they converted to a flat flange so it can carry more flow all the way out through any of the RoadsterSport mufflers. That means this midpipe ONLY works with the RoadsterSport brand mufflers. To replace the function of the ball/socket connection but allow for greater flow they use a stainless flex joint. The stainless flex joint adds significant costs but was the best way to max flow and performance all the way out. Likewise they stuff the largest and highest density packing all stainless resonator that can fit on the car so that even with greater diameter and flow the sound is mellow and fun, not harsh and abrasive.

All Mandrel bent tube with no tight bends to slow flow, see the picture and notice how smooth and flowing the bends are!

Designed as a bolt-on replacement for the factory midpipe to carry higher flow from larger pipe size all the way out any of the RoadsterSport mufflers. Simple Bolt on! Does NOT fit with factory muffler.

INCLUDES TWO O2 SENSOR CONNECTIONS which gives YOU the options later when adding headers (relocating the factory O2 sensors to before and after the converter in this midpipe from their stock location before and after the converter that is in the factory header when you replace that header to help avoid codes).

RoadsterSport Midpipe for ND

All stainless steel construction for years of driving pleasure. This MX5 Miata midpipe is larger 2.5 inch diameter pipe size. Uses high quality SPUN catalytic converter with metal core (despite presence of converter this unit is not CARB approved which makes it legal in California only for off-road/race track use). Uses monster size because when you uncork this NC MX5 Miata motor it wants to get loud unless you use a resonator this large (by comparison the stock resonator is much smaller).

Despite very large resonator, this midpipe will raise the final sound level slightly because of the much higher flow design


This unit is plug and play on Manual Transmission cars but Automatic cars have a small tab that must be cut off for fitment of this bigger diameter unit.

NOTE one gasket is included, for the midpipe exit to join with the muffler. For the front connection to stock header you stick with the factory ring gasket already on stock header outlet. If changing to our Max power header, that header will come with a gasket for that junction.

STR LEGAL under Class Rules Update 2012. Pursuant to SCCA 14.10.E: our cat fits entirely in the space that the factory cat occupied pursuant to SCCA 14.10.E....and maker certifies the core for use in any application up to 6.2L and 6000 pounds. Core has 25,000 mile manufacturing defect warranty (no core warranty for boosted or track cars), and the rest (including housings) are stainless and include a lifetime warranty.


We love the sound of this midpipe in combination with a RoadsterSport Helmholtz muffler, adds burble and throatiness when you push toward redline and controls the off throttle resonance these motors will otherwise make. We could have done a cheaper midpipe, but we decided to do the best for those of you who demand the best.


At the connection from midpipe to muffler the factory setup uses springs but you remove the springs in the use of our midpipe which converts to standard flat flange setup. That means you are using the factory studs and nuts again at the connection to muffler with the spring function being handled by the flex joint a few inches up the system.


Is one or more of your ignition coils weak or failing? One reason people buy this midpipe is that their factory midpipe converter has failed after 50,000 or more miles. The owners too often assume the failure is simple old age. Failing items such as coils, fuel pressure regulators, spark plugs, valves, plug and ignition wires, and improper ECU calibrations, can cause the engine to misfire and dump raw fuel into the catalytic converter, which will cause over heating and a meltdown in the converter, which is not a manufacturing defect in the converter. If you simply replace the midpipe and don't fix the failing car then you can expect to quickly kill any replacement converter and that replacement will NOT be a warranty replacement. Therefore, please have your car professionally inspected and repaired BEFORE you install your new midpipe.

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