Why Do Rotaries Suck?

[KezR33]

Who here when they first found out exactly how a rotary worked did not think to themselves: f**k. That's clever.

I took a look under the hood of my mate's S1 RX7 the other day and realized for the first time just how small they are too! I knew they were small, but this thing took up less than half the engine bay. It was all intercooler (V mount) and body kit up front. Yet this thing still makes over 250rwkw with minor modifications and a conservative boost.

So, reliability and fuel efficiency aside, why aren't there more rotor engines?

I understand the yanks love their big engines, but I'm sure they'll jump on board with a BIG (6-8?) rotor NA engine. I don't know anything about the engines beyond the most basic explanation, but surely if they can make the little 1.3L tri-rotor fit in half the hood of a tiny RX7, surely a Mustang with an engine bay twice the size could house an engine 2-3x as long.

What about AWD. Why hasn't Mazda created a crazy lightweight AWD rotor to compete with the GTR, Evo and STi?

Is it just... a lack of popularity? Technology? What's holding the ol' Wankel engine from really competing?

[2LV8ETR]

So, reliability and fuel efficiency aside, why aren't there more rotor engines?

You've answered your own question.

They are thirsty buggers and their weakest link is the apex seals.

[NORBY]

rotaries generally dont make much power until about 5k rpm+

[GTS4WD]

rotaries generally dont make much power until about 5k rpm+

But they rev to twice that!

A rortor on full song sounds amazing!.. Like a swarm of pissed off killer beez in a small jar!

Power delivery is so smooth in a well built rotor too!.. and when you think its all over, you realise you still have 3,000 more RPM

Im glad people are realising that rotors are not as people think.. people are just sheep..

And no.. they dont need to be re built every 10,000km

[FineLine]

But they rev to twice that!

A rortor on full song sounds amazing!.. Like a swarm of pissed off killer beez in a small jar!

Power delivery is so smooth in a well built rotor too!.. and when you think its all over, you realise you still have 3,000 more RPM

Im glad people are realising that rotors are not as people think.. people are just sheep..

And no.. they dont need to be re built every 10,000km

A sheep I am not. I am a bloke and I happen to think rotorys blow goats. Without a doubt the most obnoxious sounding internal combustion engine ever invented, Anything sounding that loud would need to make the same horsepower as a top fueler to impress me.

That and the above mentioned weaknesses inherent in the engine since day dot do nothing to endear them to the majority of car enthusiasts.

If its a rotor its a temporary motor.

[GTR-32U]

The drawback , Most Rotaries Without forced induction struggle to make any sort of Torque. I mean they still will make good Horsepower, But Try having 3 heavy guys in the car and Power uphills in top gear......

[HEKT1K]

i was thinking this myself today... was on the freeway with a clean FD... some old guy driving.

i guess it's just too alternative for a lot of people

[[WLDCRD]]

I understand the yanks love their big engines, but I'm sure they'll jump on board with a BIG (6-8?) rotor NA engine. I don't know anything about the engines beyond the most basic explanation, but surely if they can make the little 1.3L tri-rotor fit in half the hood of a tiny RX7, surely a Mustang with an engine bay twice the size could house an engine 2-3x as long.

twin rotor is the 13B. triple rotor is the 20B. quad rotor is the 26B

i always liked the look of an FD RX7 and thought if i ever got one, i would want a 20B in it..........until i sat in one. I found it too claustrophobic. So i bought an R32 GTR instead (R34 was too expensive at the time and an R33 was just too ugly)

And to the person that said its a temporary engine......so is an RB26! any modified engine is for that matter

[Taxi_This]

Can you and if so why don't please either supercharge the rotar or twin charge it? Seems obvious a blower and a rotar would be love but I have never heard of it?

[2LV8ETR]

I too share the same sentiment.

While the RB26DETT is an amazing engine, it too has its fault as do all engines.

I am a bit partial to the rotary as the power to displacement ratio is excellent, and there's nothing like the sound and sight of a huffed rotary at full song pulling a 50M wheelie.

I like them all, from V12's, to V10's, to V8's to sixes to fours, and to rotors, they all have a purpose that another may not match or fulfill.

Try swapping a V12 from a Lambo into an RX-3 and a 13BT into a Lambo. It just won't work as well.

[[200]]

They don't suck.

It's the small minded people that don't know anything about them that give them a bad wrap. I have owned 3 and I never had a single problem with them at all and I dare say the people that bad mouth them have never even owned one.

Just like anything mechanical (and female) they can have issues when mistreated.

[Birds]

As people have said, fuel efficiency...reliability...torque...

Even though rotaries are more reliable than the internet consensus going around, they are still nowhere near that of your run-of-the-mill 4-stroke engine. Porting, the most popular/drastic modification for a rotary, is largely responsible for this poor reputation. You can draw something of a correlation between how ported the rotary is and how long it will last. In contrast a stock and well serviced rotary will last a long time (Mazda wouldn't have warrantied the things if they weren't going to last atleast 100,000km).

All the fuel of a V8, none of the torque...they will never catch on for Americans because most American cars need low down torque. Rotaries are well suited to the smaller/lightweight cars - Mazda have tested/used them in heavy cars and they all fail except for the 90's generation Cosmo, which had a twin-turbocharged 20B triple rotor engine (by rights equivalent to a 9 cylinder, twin-turbocharged 4 litre 4-stroke engine). Though the Cosmo was no production car success (thanks largely to the Toyota Soarer), the 20B engine is a popular conversion for RX7 owners. The exhaust note is an each to their own thing, but you either love it or you hate it...I'm not a fan of the sound myself. Great engines for small cars though - the 13B has such a smooth feel to it when you are revving in neutral.

[JAS-25T]

They don't suck.

It's the small minded people that don't know anything about them that give them a bad wrap. I have owned 3 and I never had a single problem with them at all and I dare say the people that bad mouth them have never even owned one.

Just like anything mechanical (and female) they can have issues when mistreated.

And you knew how to mistreat them.....

[Lithium]

The drawback , Most Rotaries Without forced induction struggle to make any sort of Torque. I mean they still will make good Horsepower, But Try having 3 heavy guys in the car and Power uphills in top gear......

13Bs are fairly comparable with your typical smaller NA 6 cylinder in torque to be honest, the torque thing IMHO comes from the days where the only fast cars were V8s etc and the same "no torque without FI" sentiment also applies to RBs, SRs etc.

Here's a RX7 from NZ running an NA rotary with more torque NA than GTRs come out with:

Edited September 14, 2009 by Lithium

[[200]]

And you knew how to mistreat them.....

Nothing an uppercut doesn't sort out.

Or are you talking about the rotor?

[Rekin]

My friend who works at mazda warranty says customers of rx8's are advised to check their oil level every 2nd tank up of petrol.

Try telling that to regular joe-schmo who bought the car only based on its looks lol

[JAS-25T]

Nothing an uppercut doesn't sort out.

Or are you talking about the rotor?

Nah the birds you used for golf balls.

[Birds]

I'm a golf ball?

[R31Nismoid]

Rotar's dont suck! They are a great motor for what they are.

Try build a higher end one that makes some decent mumbo - you'll soon realise how affordable they can be.

Whilst the economy and low end toqrue isn't there, the trade off its more RPM and generally in a lighter car.

Horses for courses really

[astrotristan]

Josh summed it up well in a discussion just before;

Put it this way, we were all born from an in and out motion. Not around and around.

Therefore, using my theory, piston motors are better

The end.