Power Restored - 1997 Mazda MX-5 Miata Long-Term Road Test

1997 Mazda MX-5 Miata Long-Term Road Test

  • Full Review
  • Pricing & Specs
  • Road Tests
  • Comparison
  • Long-Term (10)

1997 Mazda MX-5 Miata: Power Restored

May 23, 2013

1997 Mazda MX-5 Miata

Holy crap. Project Miata's new catalytic converter has really reawakened this ol' tic-tac. To recap, the car had been feeling gradually less peppy, and finally the check engine light illuminated. At that point the car was also more detonation-sensitive than before and drivability had degraded a bit, too. But none of these aspects were overly prominent, just a collection of incremental nuances that I apathetically chalked up to age and hard use.

I discovered that its catalytic converter had gone bad and replaced it. Upon startup I immediately noticed the deeper exhaust note. This is an indication of reduced backpressure. Basically, the old cat had become a huge exhaust restriction, a banana in the tailpipe. The backpressure was choking off the engine. In the words of an old racer friend, the engine "couldn't eat 'cuz it couldn't poop."

Replacing the cat made far more difference than I expected it would. All of its earlier bad behavior is now gone. It drives with the verve it had when we first installed the supercharger, and its propensity to ping is now no different than then, too. The power's been restored. No joke, according to my finely honed posterior dynamometer, Project Miata had lost about 50 hp with the old and crumbling cat.

Jason Kavanagh, Engineering Editor


  • agentorange agentorange Posts:

    I thought you guys had some cooling tweak to prevent the pinging? Mind you, California's max octane of 91 probably does you no favours.

  • noburgers noburgers Posts:

    please post updates more frequently! I'm in withdrawal--3 weeks and no new news. This long-term test inspired me to pick up a friend's '96 Miata, so I'm more motivated to read the updates than ever before.

Leave a Comment

Past Long-Term Road Tests

Have a question? We're here to help!
Chat online with us
Email us at help@edmunds.com
*Available daily 8AM-5PM Pacific
Call us at 855-782-4711
Text us at ED411