FEATURE STORIES

Our Favorite Engines: Suffering with - and enjoying - Mazda's 13B rotary

Our Favorite Engines: Suffering with - and enjoying - Mazda's 13B rotary image

Aurick Go / Manufacturer Press, Aurick Go, Jose Altoveros | May 15, 2018 15:05

A first-hand account of life with a pistonless engine

The rotary engine, rare in itself, is an uncommon sight on our local streets. With only a handful of properly running RX-7s and RX-8s in town, the chances of seeing one are quite slim. But if you hear the unmistakeable sound akin to a loud barrel of bees revving in the distance, you will likely understand the charm and character these motors possess. 

I see the rotary engine as the road less travelled; Its unconventional layout and lack of widespread expertise means living with this engine can prove quite a challenge – a challenge I’ve accepted since I bought my RX-7 back in 2015. Allow me to share with you what it feels like to own a rotary-powered car, not to mention what it takes to keep the 13B-REW running.

Our Favorite Engines: Suffering with -and enjoying- Mazda's 13B rotary

Ownership of a rotary engine is something I would liken to having a set of extra rituals: maintaining and keeping it in tip top shape involves being very religious with checking things that are otherwise negligible in a normal car. Things like checking for oil and water in the cooling system are more of a routine every outing rather than a once-a-year type of deal. To ensure that the rotary engine is in perfect shape, every symptom has to be noted and dealt with as soon as possible – and it starts with checking for fluids and how they behave. Oil and water are key components of the engine’s lifeblood after all.

Speaking of symptoms, I believe in keeping high performance engines in check with a healthy amount of information from gauges and meters. Things like air/fuel ratio gauges, boost, water temp, oil temp, and oil pressure are your telltale signs towards any anomalies inside the engine. For the 13B-REW, this is doubly important considering one false step could blow the motor – not to mention have your friends joking about your apex seals again. People say that ‘Ignorance is bliss’, but on the flip side ‘knowledge is power’. When you have a motor that’s pushing roughly 400PS it would definitely be wise to subscribe to the latter.

Our Favorite Engines: Suffering with -and enjoying- Mazda's 13B rotary

Truth be told, all the horror stories and jokes about the rotary engine being ‘disposable’ all point towards one true cause: a lack of lubrication. What you have to understand is the 13B-REW – and the engines that precede it – all have a device called an oil metering pump (OMP) that injects a small amount of motor oil into the rotor housings at every combustion. The engine was designed to eat oil, and if you read the RX-7 owners manual it will indicate that the motor will have to have its engine oil topped up now and then. Now, some negligent owners fail to realize this and eventually run their engines to the ground, but in most cases the OMP itself has a very critical flaw. You see, the OMP will not have any symptoms upon failure – meaning whether you keep the engine in check or not, it will tear itself up from lack of lubrication.

Our Favorite Engines: Suffering with -and enjoying- Mazda's 13B rotary

The critical failure of the OMP means rotary owners have to get creative with how to inject lubrication into the rotor housing. The solution comes in the form of pre-mixing 2T oil into the gas tank at every fill up. A ratio of roughly 20L of fuel to 100ml of pre-mix should ensure that the engine stays lubricated for the duration of the tank. Talk to any tried and true rotary owner and they’ll just say pre-mixing is just another ritual in rotary life. 

On the road the 13B-REW feels odd if you’re used to a conventional inline-4. While its rev counter goes all the way up to 9,000 (with the redline somewhere at 8,500) you will notice the lack of torque until the turbo kicks in at about 4,500 rpm. Mind you my current setup is that of a Single Turbo – a choice that was made in the interest of reliability over the complicated factory twin turbos. Once the boost kicks in though, a surge of power will have you missing the redline if you blink. Shifts go by really quick once you’re on the powerband, meaning the rotary engine is actually closer to a motorbike engine than it is to a conventional car. High-strung, upper-range powerband, and running on 2T to boot. All too similar indeed.

Our Favorite Engines: Suffering with -and enjoying- Mazda's 13B rotary

Thanks to its absurdly light weight compared to a piston engine, the rotary lends itself well to a proper balance for the body. That said, the RX-7 can almost become telepathic when sharply turning into a tight chicane. On sweeping corners the RX-7 becomes very lenient by gradually rotating its body into the apex. It’s true point and shoot material without any electronic wizardry, all thanks to a rigid chassis, proper weight distribution, and clever engineering.

Our Favorite Engines: Suffering with -and enjoying- Mazda's 13B rotary

Fuel consumption is something you shouldn’t bother measuring when owning a rotary – lest you’ll end up crying over spilled milk. 3km/L is pretty much the norm for the triangular lump, with numbers getting worse as you pile on the modifications. A rotary engine will most likely be tuned to run fairly rich in order to get the most out of it. That means you’ll also likely be putting on a show for your friends following behind you with a healthy amount of backfire. My friends tell me it’s quite the spectacle, ah how I envy what they get to see.

Our Favorite Engines: Suffering with -and enjoying- Mazda's 13B rotary

Odd and unconventional as it is, there is truly nothing like the 13B-REW. I will be the first to admit that this engine isn’t for everyone and that its rituals can be cumbersome. But despite all the inconveniences of running rotary, I’m still driving one anyway.