Good-Win Racing Mazda Performance Parts

RoadsterSport CARB CERTIFIED Midpipe with Catalytic Converter and Resonator


Miata 1990-2005 · Exhaust · Catalytic Converter

Part Number: 61-1221b

Application: 1999-2000

Price: $499.00


RoadsterSport CARB CERTIFIED Midpipe with Catalytic Converter and Resonator
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CARB CERTIFIED using 441004-core is CARB certified for use in California for the 1999 to 2000 Miata.

The factory converter for the 1999 to 2005 Miata is a welded in part of the midpipe (California 99-00 Miatas also have second converter in the header assembly). Complete your highflow exhaust system with this midpipe...this is the best BOLT IN midpipe available for second generation Miatas and includes a highflow converter and built in resonator! Full 2.5 inches from tip to tip in all stainless steel and CARB LEGAL. ALL the mufflers we sell for 99-05 include only the muffler and not a midpipe (unlike the 90-97 choices). So if you want the flow to connect your new high flow header to your new high flow muffler here it is...for normally aspirated to supercharger or turbo (BUT does NOT fit MAZDASPEED). All stainless steel parts means years of quality performance and all the stainless parts have a lifetime warranty (300-cell ceramic catalytic converter used on all units sold in 2012 or later includes a 5 yr/50,000 mile manufacturing defect warranty on its housing and 25,000 mile manufacturing defect warranty on the internals). CARB approved and legal in California. Not for use with Racing Beat's lower rear chassis brace.

INSTALLATION: See Forum Installation Section! The slip joint in the middle of this item is your friend, lube it up and adjust length and clocking position as needed (if you ignored this note and shoved both parts fully together you made it all too short and that will cause contact with the differential which you can cure with just adding some length at the slip joint).

INSTALL NOTES and CAUTION! Is your Ignition Coil weak or failing? The most common reason people buy this midpipe is that their Miata midpipe converter has failed after 50,000 or more miles. The owners too often assume the failure is simple old age, when in fact something else is failing. 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, and 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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I should thank you. The parts ordered have greatly enhanced my MX-5 and they were received well before I could have reasonably expected them. I'm an enthusiastic new customer. Regards, John

-- John W.

After reading many other positive reviews on both the GWR and Miata forums I finally decided to buy this product. My main concern for many months was whether or not I was up to the task of installing the header. But with the excellent instructions on Brian's forum as well as several Miata forum threads it turned out easier than I expected. After receiving notice that the header would arrive on a Friday afternoon, I began the disassembly process. After about 3 hours I had the stock manifold out. Later that afternoon the new catted header arrived right on schedule. And it is a thing of beauty. I opted for the stainless version. Installation on Saturday morning took another 3 hours, although I could have shaved some time off of that but I was actually enjoying the process of double checking torque values and cleaning up my engine compartment. I already have the GWR catted midpipe, so that connection was a snap. I put everything back together, reconnected my battery, and went for a drive. NO CODES! Nice throaty sound with my RSII muffler, and a significant boost in power and low/mid torque. Another happy camper here. I since have added a M-E tune and I feel I have realized all of the gains that Brian has achieved on his 2012 project Miata. I've put several hundred miles on my Miata since the install with zero problems. This is the car that Mazda should have built all along. Thanks Brian.

-- Ron P.