Rotary (Wankel) engines used to be a standard for many motor-driven vehicles, but thanks to significant efficiency advancements and cost-effectiveness, the piston-driven engine prevailed. Rotary engines are not as economical because they offer a lower compression ratio and thermodynamic efficiency.
On the other hand, they are a lot smoother and quieter because there are fewer moving parts inside a rotary engine and those parts are slower to move. The compression ratio of a rotary engine is lower, inner engine components also move slower which in-theory makes them more reliable long-term.
Mazda is a brand known for making great rotary engines, and the Mazda RX-7 and the RX-8 are the two most popular Mazda rotary engine cars. The Citroen GS Birotor was also available with a rotary engine, but the GS Birotor failed to be reliable and efficient which meant that only a few hundred of these were ever built.
NSU was a German car brand from the Cold war era, the NSU Wankel Spider and the NSU Ro80 were the two best cars they ever built, both with rotary engines. The most amazing car with a rotary engine is the LeMans racer Mazda 787B, the only rotary engine car that has ever won the 24hrs of LeMans.
Mazda RX-7 – JDM Royalty
If you are a car enthusiast, chances are that you are already overwhelmed by the RX-7 because this rotary engine Mazda sportscar is one of the most famous JDM tuner cars to ever exist. The RX-7 is available with a 12A Turbo or non-turbo engine, 13B engine in either a non-turbo, single turbo, or sequential twin-turbo configuration.
Some say that the RX-7 is the very best drift car that has ever existed, but the beauty of the RX-7 is that it can deliver pretty much in all aspects of spirited driving. The ones to get are the second-gen RX-7 or the superior third gen. $2500-$3000 is the lower you’ll have to pay for the 2nd gen while the third-gen RX-7 costs more than twice as that on average.
Mazda RX-8 – Worthy successor to the RX-7
It’s impossible to talk about rotary engines without mentioning Mazda, and the RX-8 is also at the very top of the best rotary engine car list. The RX-8 was the last true rotary engine on the market, and the RX-8 ceased production in 2012. The RX-8 had a lot of hype to live up to considering it was the RX-7s successor.
All things considered, the RX-8 lived up to the hype because the 13B engine had all the great characteristics a rotary engine should have – smooth power delivery, high RPM range, crazy sounds. However, it also had all the inherent drawbacks of a rotary engine, and that is fuel inefficiency and poor reliability.
Citroen GS Birotor – Nice try Citroen
The Citroen GS is probably one of the greatest hits Citroen has ever made, but the GS Birotor certainly does not fall into that picture. The official name was Citroen GZ, but most people referred to it as the Birotor GS. Nevertheless, the BS Birotor offered an incredibly smooth power delivery and the hydropneumatic suspension was amazing.
However, the 1970 oil crisis began and it signaled a downward spiral for the GZ Birotor because it was an incredibly inefficient car which comes as no surprise. After all, rotary engines are inherently inefficient. Less than 900 of these were ever built and Citroen wanted to disown the model completely but failed to do so.
NSU Spider/NSU Ro80 – Grandfathers of modern Audi
NSU was situated in former West Germany and it was the very first western brand to develop a rotary engine. The two most popular models were the Wankel Spider and the Ro80, both of which offered a 995cc rotary engine with around 105bhp.
Both of these are front-wheel drives, but reliability was a big concern. It’s worth mentioning that modern-day Audi had its roots in the NSU car company.
MAZDA 787B – An icon of motorsport
The Mazda 787B is the only car equipped with a rotary engine to ever win in the most prestigious motorsport even of them all – The 24hrs of LeMans. As such, it comes as no surprise that the values of Mazda 787B racecars have literally gone through the roof at more than 2 million dollars.
The 787B is equipped with a 4-rotor 700hp 9000RPM engine, the combined power to weight ratio of the 787B is 843hp per ton. The 787B is characterized by a screaming engine sound that is so loud that the 787B can not even be used on most modern-day racetracks.
Are rotary engines making a comeback?
For quite a few years now no one was interested in making rotary engines because they cost a lot of money to develop and they cost a lot of money to run. However, Mazda has confirmed that they will be making a car with a rotary engine for the 2022 model year.
However, the car in question is not going to compete with the likes of the RX Mazda family because the engine is intended for the Mazda MX-30, the upcoming Mazda EV/Hybrid. Be that as it may, designing a rotary engine for any purpose certainly means that the rotary engine still has something to offer, even in 2022.
Are rotary engines more reliable and cheaper to maintain?
In theory, they should be, in practice not so much. As mentioned previously, rotary engines are comprised out of fewer moving parts which means that there are fewer problems to be had with a rotary engine.
However, history has shown that rotary engines are not really any more reliable than their piston-driven counterparts. As far as maintenance is concerned, they are cheaper to maintain, but only if you know what you are doing because maintaining a rotary engine is a completely different story.
Which rotary engine car is the best to buy?
The best rotary engine to buy right now is probably an earlier Mazda RX-8 model because it can be had for less than $10k for a decent example. Of course, the RX-8 is not all that reliable, but it ain’t terrible. This especially makes sense if you know a thing or two about maintaining rotary engines yourself.
The RX-8 is a stepping stone between a bygone era of Mazda rotary engines and modern-day consumer daily cars. This means that the RX-8 can be driven daily, but it can also be tuned to produce silly horsepower and it can also drift of demand.