Good-Win Racing Mazda Performance Parts

RoadsterSport Stainless MX5 Miata Midpipe with Converter


Miata MX5 2006-2015 · Exhaust

Part Number: 60-1328

Application: 2006-2015

Price: $399.00


RoadsterSport Stainless MX5 Miata Midpipe with Converter
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Designed as a bolt-on replacement for the factory midpipe to carry the 2.5 inch outlet of the factory header, and our RoadsterSport and Racing Beat headers, all the way to your choice of any of our 2.5 inch inlet RoadsterSport mufflers. Simple Bolt on for MANUAL TRANSMISSION ONLY, can be installed on Automatic but see page four of our forum header install thread for details of what is required. Also bolts up to our Racing Beat exhaust, MazdaSpeed exhaust, stock header and Racing Beat header.

INCLUDES TWO O2 SENSOR CONNECTIONS which gives YOU the option to later add our RoadsterSport or Racing Beat 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 midpipe).

All stainless steel construction for years of driving pleasure. This MX5 Miata midpipe is slightly larger diameter than stock at 2.5 inches all the way through (see torque gains in our forum dyno thread). 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 18 inch resonator because when you uncork this NC MX5 Miata motor it wants to get loud unless you use a resonator this large (by comparison stock resonator is about a foot long).

Stock midpipe is 20 pounds, our midpipe is 16.5 pounds for total savings of 3.5 pounds. Despite very large resonator, this midpipe will raise the final sound level just slightly because of the higher flow larger diameter tubing.

BRIAN'S APPLICATION NOTES: We started with the much larger "two biscuit" cat we use in the 99-05 midpipe system but I didn't like the sound quality that resulted. This small single biscuit spun unit is actually more expensive than the big metal clamshell cat we use in the 99-05 system but we did some experimenting with cats of different sizes and the short chambered spun cat helps reduce that 3000 rpm DRONE/ BOOM that this motor really wants to make on decel when uncorked. The short cat also saves another 1.5 pounds as compared with the bigger cat.

As for sound level...with the big cat the sound volume level was really unchanged as compared with the stock midpipe but we made the tradeoff decision to reduce decel drone but finish with slightly higher overall volume using the short chambered spun cat. and I think most will appreciate this choice.


Read full installation hints and notes in our forum Installation Instruction Section! --- CLICK HERE TO READ MORE.

STR LEGAL under Class Rules Update 2012. Pursuant to SCCA 14.10.E: our cat is smaller than stock but fits entirely in the space that the factory cat occupied pursuant to SCCA 14.10.E....and Magnaflow certifies CA/CE 59956 cores for use in any application <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.

INSTALL NOTES and CAUTION! 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.

INSTALL TIP: READ our installation notes in our forum Installation section, the slip joint in the middle is your friend and the mistake some will make is to shove both sides of the midpipe fully together, making it too short. Lube up that slip joint and adjust length as needed.

*** Product images may differ from actual product appearance ***


Just wanted to thank you guys for the great stuff and great work done on my MX5 club yesterday. I could feel the difference in sound and performance right away! It drives and corners awesome now. Can't wait to tell my friends about you guys. I'll be keeping an eye on your web site for other goodies and events as well. Can't wait to try my new suspension out on a auto cross. Will definitely be trying it on some twisty roads this weekend. Just can't wipe that smile off my face when driving this car. Thanks again guys!

-- Paul Young

You guys are great! The new suspension is in and the ride is much improved. Thanks for the great service.

-- Chuck