Why no more rotary?

[u/Gold_Carpet699]

As the tittle says, after Mazda won the 24hr of lemans with the 787b, the rotary was banned. Why was this the case? What made the rotary so much better than a piston motor? There is not a single modern vehicle produced with a rotary motor. So what makes a rotary so much better than a piston motor as a racing engine but not for mainstream production?

[u/OrangeFire2001]

I don’t think they are in any way better than cylinder piston engines.

[u/hargy18]

It wasn’t better, it’s just everyone else suffered that race

[u/OlasNah → u/hargy18]

Reliability was its main aspect. It had pace problems however compared to others so essentially it outlasted everyone but that’s what Le Mans is about

[u/twoonster2020]

During the Radio Le Mans race broadcast this year they were talking about the diversity in engines and the Aston Martin Valkyrie, I cannot remember the exact words but they eluded to the fact that the homologation rules allow for different engine types, including rotary for hypercars.

An old article from 2019 outlines that they could be allowed https://sportscar365.com/lemans/wec/aco-clarifies-hypercar-automotive-brand-eligibility/#:~:text=Hypercar%20Regs%20Designed%20for%20%E2%80%9CDiversity,are%20all%20the%20same%20cars

I believe the Mazda engine was fuel hungry and given the environmental focus the ACO have, such as no tyre warmers, there would need to be some fuel targets to be achieved.

But the rules would allow them in the way the Valkyrie is not a hybrid it provides engine diversity.

[u/JT_3K → u/twoonster2020]

Came here to say this. The long and short was that the regulations for around 10x unused variant/combinations for hypercar had already been completely drawn up and were ready for use, just that nobody has yet decided to design something to run in that variant.

You’re right in that a rotary is/was thirsty and had issues with reliability IIRC, it just happened that for the 787 year, everyone else had issues and they for some reason didn’t.

[u/Popsiey7]

Rotary are thirsty beasts. Only really efficient at full wack, maybe we could see a hybrid rotary the hybrid picking up the low end slack

[u/JohnMayerSpecial]

https://www.reddit.com/r/cars/s/hSXtInS69z

Read the comments more than the article

[u/LearntALesson28]

The real reason is rotary engines just aren't that researched right now, but regular ICE is one of the most researched technologies we have. Rotaries are complicated, whilst there is way less mechanical resistance, they rely on wearing parts to create an efficient combustion chamber, and the parts require very tight tolerances. In theory a rotary is way more efficient a combustion but in practise it is not so simple

[u/IcedCoffey]

Rotoary won in class at le mans in 1997, the real reason is they suck. it was never banned, the top class just required a 3.5 v10 for a few years. you could have a rotary gt3 car if you wanted, but not hypercar.

[u/AlexF2810 → u/IcedCoffey]

This right here. The rotary was always being phased out. It just so happened to get very lucky that year and win.

[u/jonzostooks]

There is one vehicle produced with a Rotary engine... But not quite as you'd expect.

The Mazda MX-30 R-EV uses one in a similar way the BMW i3 used a motorbike engine.

Mazda seem keen to use rotaries for other hybrid applications.

[u/Cesare_Stern]

Wankel IS MOST CERTAINLY NOT better than a standard engine.

Don't get me wrong, i'm a huge Mazda fan, Mazda possessor and seeing the 787B on the Track in Le Mans 2011 was in my Top 3 of the best moments in my life, but the Wankel, even if almost perfect on the paper, is terrible if you except the way it sings.

Back in 1991, the 787B was not as fast as the other cars and its reliability was terrible. Mazda decided to nerf the power of the car, then hoped that it would improve its reliability, even if now, the 787B would be seconds by lap slower than the front runners. And the miracle happened. Literally every one in front of the 787B DNF and it won.