Dear Turbo,
I am a fairly new reader and I can't begin to describe how much I have gotten out of Turbo. I know the basics of the rotary engine, but there is one thing that has always bothered me. Why is Mazda's rotary engine sometimes referred to as a "Wankel." I know this is not the hard-hitting tech question you are used to, but maybe other readers have also been wondering the same thing.Adam SacuyVia Internet
Adam, the rotary engine is a unique beast and with the outrageously impressive Rotary Performance RX-7 we have on the cover, I have decided to answer your letter in my column. Mazda's rotary engine design is sometimes called a Wankel after its creator, Dr. Felix Wankel. The rotary engine was originally developed by NSU of Germany in the early 1950s. In 1960, Mazda acquired the licensing rights to the unique powerplant. It was an entire 10 years of development on Mazda's part to conceptualize and construct a rotary design worthy of use in a production vehicle.
In the U.S. market, the 1970 Mazda R-100 was the vehicle that introduced rotaries to the States. American tuners were intrigued by the radically different design and began to tinker with the engine and figure out what made it work. This, of course, led to creative methods of performance enhancement. Forced induction was attempted but the results were disheartening at best. The turbo rotaries would produce prodigious power but lived a very short life on boost as the early apex seals were not equal to the task of containing boost pressure. The answer for performance junkies was to use the engine's lack of a valvetrain as an advantage and spin the rotary to stratospheric engine speeds in order to extract more power.
In 1974 the Mazda RX-4 sported an updated rotary engine which ran a much more stout apex seal, making boost a viable option. However the gas crunch and a re-valuation of the Yen coupled with the poor fuel economy of the rotary put a big damper on the party. The RX models were replaced by piston-powered variants until the RX-7 bowed in 1978 with better economy from its Wankel and a different approach to styling.
As automotive electronics evolved and fuel injection hit the scene, the idea of a factory turbocharged rotary became more and more feasible. The first-generation GSLE RX-7 relied on a fuel injected engine and the lessons learned with this system and Mazda's extensive racing programs of the day led to the boosted RX-7 Turbo II of 1986. It was a perfect match. Due to its design, the rotary's unique "firing cycle" allowed the quick-revving rotary to generate a great deal of exhaust energy for its displacement and a turbo could effectively harness that energy and make power with it. The aftermarket went into Warp Drive when the Turbo II hit and by the time the FD rolled out in 1992, there was an entire rotary subculture waiting to turn up the wick.
There are plenty of rumors that have Mazda bringing back the rotary and there have been a few concept cars with rotary power spinning on pedestals at motor shows. Some of the stronger rumors are a Wankel sedan to fight the Lexus IS 300, BMW 3-Series and Audi A4. There are also rumors of the RX-7 itself making a comeback with a lower price tag. What about a rotary? What about turbos? We don't know and are hoping for both. Time will tell.
I hope this quick explanation adequately answers your question. Stay tuned. Evan Griffey