Putting the synthetic vs mineral motor oil in a rotary debate to rest

Over the years there has been much debate on whether synthetic motor oils can be used in rotaries. Previously, FCs & FDs did have seal swell issues due to reaction with additives in a relatively infant synthetic oil industry then. Today, there are a whole new range of synthetics – from PAO esters, double esters etc. Note however that some oils labelled fully synthetics are severely hydrocracked (read refined) dino oil – only the pure PAOs can be considered lab created. Then again, it is not uncommon to find mixtures of hydrocracked dinos and esters marketed as fully synthetics. So, will today’s synthetics cause problems with the RX-8 SE3P?

Yes and no – rem that a rotary engine needs to inject and burn motor oil for cooling and lube at the same time. If the oil doesn’t burn cleanly (and the culprit most of the time are additives and high-ash content), then deposits are left behind – that of course isn’t ideal.

So should we still use synthetics? Yes – synthetics by definition have qualities that can only benefit the rotary, BUT use only synthetics blended by rotary tuners, have proven efficacy, or are guaranteed by the oil manufacturer. Use anything else and it could be a case of Russian roulette. The brands i’ve used without problems and i highly recommend, ranging from 30wt to 50wt viscosities include:

 Idemitsu Fully Synthetic Rotary (avg S$170 per oil change, limited availty at Monster Garage)
Trust F2 Synthetic Rotary (it’s actually a semi-syn. Avg S$150 per oil change, avail at Autobacs)
 R-Magic Racing Energy for Rotary (Fully Syn, avg S$270 per change, avail at Autobacs)

So the advice from RXReviews is NOT to use any other non-rotary synthetic for now, until Mazda issues a circular stating otherwise – the safest bet is to go back to Shell Mineral, but the smoothness and slight performance advantage synthetics bring is compelling. Myself? I use Idemitsu 30wt and i’m very very happy with it.

And for those who’s asking what ATF oil i use? Redline Fully Syn High-temp ATF. It def makes the tranny smoother, a very slight performance increase but most importantly, peace of mind as i really whack my gears!

Ultimate Driving Watches

A watch nut that i am, i’m updating my collection to fit in with my passion for cars. Here are some watches that I highly recommend for the driving enthusiast – without breaking the bank!

Those I own:

Seiko Sportura Limited Editions, Tissot T-Race

One I plan on owning sometime soon:

Zenith Defy Extreme

The one that i’m searching high and low to find:

Mazda Rotary II Watch, available at Mazda Australia at aga AU$329, and Apex-Auto-Parts.com at US$175 + shipping.

RE Amemiya Exhaust Manifold

Singapore’s first RE Amemiya exhaust manifolds for the RX-8 is arriving anytime this week. RXReviews will bring you the review of this sweet performance mod as soon as it’s in – and for the 4AT!