Our Miata recently participated in a little autocross test day, so it first received some attention. First, in an effort to stabilize handling, we swapped the Racing Beat rear anti-roll bar for the stock piece. We normally don’t mind a little extra rear bar, but our car had become a little too tail-happy when fitted with Racing Beat piece. Fortunately, swapping Miata rear anti-roll bars is about a 10-minute job.
We also had BSI Racing (http://www.bsiracing.com) install our Kaaz limited-slip differential. This is a clutch-style diff, and since BSI has recently jumped into the Spec Miata market with both feet, the job wasn’t too hard for them. During the install, they also rebuilt the differential, replacing all wear items.
The Kaaz paperwork says the differential will be a little noisy at first, and they’re 100-percent correct. However, we have been following the break-in instructions, and the noise level has been dropping. Under power and during autocross-type moves, however, the locked diff produces no noise. When making slow, tight turns, there is some chatter as the clutch plates get friendly.
With the new diff and smaller rear bar, our testing revealed a new car—we can easily power off the turns, the energy once used to produce tire smoke now propelling the car, while a little trail-braking will get the rear end to rotate just right on corner entry. Can’t wait for our first competition event this season.
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