THSCC Forums

I bought my '93 Miata two years ago. It has has been regularly bounced off the rev limiter autocrossing and spent lots of time on-track.

I have used both 5W-50 Synthetic and 5-30 Synthetic from several "brand" manufacturers--Quaker State, Mobil, Castrol. Oil gets changed every 3 autocross events or before and after every track event, averages about every 100 miles or so.

Can't notice any difference between 5W-50 and 5W-30, except that this particular Miata experiences occasional valve lifter clatter only when the 5W30 is present. So... I'd recommend going with 5W-50 Full synthetic.
Go figure.

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Brad

Guess I'll find out what it's like to be a Rotella fella

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“I feel safer on a racetrack than I do on Houston's freeways.” - A.J. Foyt

Kevin Butler
Mobetta Autosport Spec E30 #612
2003 C5 Z06 Corvette
AFR Miata, SM2 61, '93 w/200 SC'd RWHP - soon to be resurrected
Waaaay too many other projects....