Rotary: Not dead yet?

I think a turbo rotary hybrid linked to a cvt is a great idea.

Rotaries are very easy to backdrive thus making the hybrid system less complex. The CVT would keep everything running in the most efficient state and rotaries do awesome on different fuel types. And due to the low torque of the rotary the CVT would last a while.

A propane/CNG turbo rotary CVT may just be a sports car best friend.

CRZ meets RX7

RX-7Zh perhaps.

Max_Archer wrote:

GTwannaB wrote: Dear Mazda stop wasting time on the rotary, please. You should have spent the effort on a hard top Miata coupe ala the new BRZ.

Yeah, but what if they make a hardtop Miata and put a 250HP 9000RPM rotary in it?

I wouldn't buy it for the same reason there is not a set of RX8 keys in my possession - crappy gas mileage, constant need to add oil, flooding issues on short trips and low torque. I have to move my car up and down the block a couple of times a week for parking issues. I would probably flood a rotary once a month. Yeah maybe they will improve the design, they might get it to run on pixie dust too.

GTwannaB wrote: I wouldn't buy it for the same reason there is not a set of RX8 keys in my possession - crappy gas mileage, constant need to add oil, flooding issues on short trips and low torque. I have to move my car up and down the block a couple of times a week for parking issues. I would probably flood a rotary once a month. Yeah maybe they will improve the design, they might get it to run on pixie dust too.

Mine doesn't have those problems.

Crappy fuel economy? I get the same fuel economy as my Volkswagen. It can't carry as much stuff, obviously, but I have two cars because they do different things.

Constant need to add oil. I have had rotaries for probably 200,000mi across several cars and none of them ever used oil between changes. My current car actually needs oil drained off. If I wait 3,000mi before changing or draining the oil, the level gets so high that it leaks out of the front seal when braking hard. (Oil dilution with fuel is a known rotary problem. Mazda developed a quick-change oil system for endurance racing. I add about 1qt/1000mi)

Low torque? I'm not sure about that. My car is a ltitle soft below 2000 but other than that there really isn't a torque curve. It just sort of has a plateau that ends when I don't feel safe revving any higher.

Solution for the parking issue - drive the thing!

If your rotary isn't using oil then you have a problem. If you have to drain some off you have a bigger problem!!!

My problem is it won't cruise any leaner than 12:1 without misfiring. Silly bridge ports.

I can run stock or even mild street ports at 16:1 under cruise. They still add fuel to the oil, although not at such an accelerated rate. Oddly enough, I still get about 21-23mpg on the highway.

I haven't had an oil metering pump on any of the engines I've had. All they seem to do is drool oil down the front of the engine instead of injecting it. Plus, I like being able to control how much oil the engine gets, run about 150:1 when driving on the street, and when it's time to thread cones, I can jack it up to around 80:1. Mazda always seems to under-oil the engines in the name of catalyst life. Plus, after 14 years of screwing with these things, 2-stroke oil just smells good I'm going to miss it when the End Times come and I have to go piston engine because parts are unavailable.

Yeah rotaries suck

In reply to bruceman:

I believe I detect a bit of sarcasm from the man with the rotating assembly for a rotary engine in his avatar.

Awesome engines. I hope they continue to develop them.

The ongoing production of the Wankel has been a roller coaster ride for me. I would love another major revision of the engine that makes it more efficient as much as I'd live another two seat rotary powered sports car.

As others have said, Mazda's R&D dollars have to cover more than just the rotary, and let's face it, if the SkyActiv project doesn't work out for them they might be in deep E36 M3. If they get bought out, I am pretty certain the first thing cut would be Wankel R&D unless somehow they got taken over by a huge rotary enthusiast.

In any case, here is to hoping that the 16A sees the light of day.

In reply to Knurled:

OK, I need to tone back the rotary hate. I would love a rotary if they fit my needs a little better. Mostly I am pissed off because there is not a RX8 sitting in my parking spot right now because the rotary makes it a no go for me right now.

It's interesting how certain hot-button topics arise. Every time rotarys come up, people have to rag on them, and let's not mention hybrids, or god help us - the Volt!

My observation as someone who has a love/hate relationship with rotaries - GRM types claim to love rotaries but seem to yank them out for a V8 transplant at the first sign of trouble, like if it needs an oil change or new spark plugs.

Rotorheads, tell me why I'm wrong.

What would be the downside to running a multi rotor engine with one small, thermally efficient chamber that is always at high load and connecting it to one or two large rotors that are usually completely unfueled but come on line when you step on the gas?

In reply to DaewooOfDeath: I'm not a rotorhead, but it seems to me that you'd still be compressing a bunch of air in the unfueled cylinders, which would make your "efficient rotor" a lot less so. Also, how would the seals be lubricated if there wasn't a stream of fuel coming through?

In reply to DaewooOfDeath:

Seems like the multiple displacement systems in piston vehicles.

Other than the rotor seals overheating, I can't immediately think of a downside.

You're still moving a lot of air, which will do unpleasant things to the catalyst. Displacement on demand engines disable the valves at a precise time in order to trap a volume of air in the chamber.

And then you still have to oil the apex seals, which can't get lubed from the backside like the side seals (or piston rings for that matter).

And you're doing nothing to deal with the major problem with the engine, namely all of that surface area.

You'd be better off doing a hybrid.

Here is to hoping it will be a pleasant thorn in the side for another 40+ years!

In reply to DaewooOfDeath:

Your idea reminds me of the 2-stage diesel Wankel Rolls-Royce once developed for an airdrop-capable AFV, except both rotors were supposed to stay engaged.

http://retro-motoring.blogspot.com/2009/03/rolls-royce-make-wankel.html

One rotor can still run when another is deactivated as long as nothing is jamming up the works, but as others here have said, doing that on purpose places greater load on the operative rotor and leaves you with a rotor that's not getting lubed. The air-pumping issue shouldn't be a problem since ports can be opened and closed as needed (normally aspirated 2nd-gen RX-7s had 6 intake ports, two of which would only open at high RPMs. It would probably be easy to make all of them + the exhaust port open and close as needed).