Slidin8

The R26B had 3 spark plugs per chamber, ran over 700hp DETUNED

A standard rotary has 2 spark plugs because the combustion area is very wide, 2 spark plugs were put there to ensure all the air and fuel were ignited

olddragger

iTrader: (3)

oh yee of little faith. materials, lubrication/temp control advancements, ignition advancements and semi direct injection could all possibly point to a lighter, more powerful rotary engine in the near future.
How about a 3 rotor with middle rotor deactivation to increase gas mileage?
Also a rotor tip design that will allow more than one seal--how about that?
I didnt say nothing--this is all wishing.....!

ken-x8

So that's one advantage of the Wankel. Lots of room for as many spark plugs as you want.

I remember an Alfa Romeo back in the 50s or 60s that had a twin plug head, not because they needed two plugs but because one in the center limited how big they could make the valves. There's always a trade.

Ken

Slidin8

my mother has a 04 Merc C320 and the V6 in those have twin spark plugs

I imagine there are many twin spark plug piston engines out there

Jeff77789

but hundreds of parts usually means less reliability since there are now more points of failure.

so if any given part has a 1 in a million chance of failure, and you have 100 parts, all of a sudden you now have 100 in a million chance for failure which is 1 in 10,000

Brettus

iTrader: (2)

that theory is rubbish in the light of how much more advanced the piston engine is ahead of the rotary .

Jeff77789

it's a perfectly valid argument. anything has a failure rate. even if all your parts have a 1 in a trillion chance of failing, 100 parts would have a 100 in a trillion chance of failing

it's like water flowing through a pipe. if the pipe has one hole in it and you patch it up with a piece of duct tape, the chance of that leaking will be 1 in 100. but if you have 3 holes that are patched up with duct tape, now your chances of water leaking are 3 in 100.....does it really matter? no. does it still make a difference? yes.



where your argument about how the piston engine is more advanced comes in is when actually comparing a rotary to a piston. lets assume a rotary only has 3 parts and a piston only has 100 parts.

if a piston engine has 100 parts with each part having a 1 in a trillion chance of failing, your failure rate would be 100 in a trillion

on the other hand, the rotary engine has 3 parts with a 1 in a million chance of failing so your failure rate would be 3 in a million


since 3 in a million is higher than 100 in a trillion, that makes the piston engine more "advanced"

with time, research and development, im sure the rotary will become just as advanced as the piston engine today

Brettus

iTrader: (2)

Not really . Just ask anyone who has been around rotaries for a long time . They can be made to last ,sure. But most piston engines last way longer . It's just a fact . Doesn't matter how many moving parts you have if the design is inferior ....

ken-x8

And speaking of parts count...how many parts are involved in a Wankel's seals? And how delicate is it to get those installed properly? Compare that to piston rings.

Of course, even with piston rings being inherently more robust than apex and side seals, how many decades of ring development did it take before piston engines were not expected to burn oil? So development time is still a big deal.

Ken

Marklar

Yes I agree, but the key part is "as the piston engine is today." By then piston engines will be more advanced, there is just no way that Mazda can develop the rotary at the pace that piston engines are being developed.

This is reality (though I don't think it's due to an inferior design). A Toyota four-banger is a hell of a lot more reliable than any rotary. The rotary does have some theoretical design advantages when it comes to reliability, but this is far out-weighed by the fact that piston engines are much more evolved. Rotaries are relatively primitive, they've been around about half as long as piston engines and for most of that time they've only been made by one small car company.

Orthonormal

If that's all there was to it, then the rotary ought to be super reliable, right? Uh-oh.

RXeligion

To piggyback on this idea a little...

Mazda turned a 2 door purist car into a 4 door touring car and gained 200 lbs.

Porsche tried the same thing with their 3,042 lb Carrera, and came up with the 3,800 lb Panamera.

Technical Specs - Panamera - All Panamera Models - Dr. Ing. h.c. F. Porsche AG

Marklar

Yes, but is the 8 really a 4 door touring car? It actually created a gray area between coupe and sedan. It's really more of a large-ish 2+2 coupe. Not really the same thing as a full-sized sedan like the Panamera.

> MAO <

Brettus seems to be the only one with a straight up answer

Jeff77789

ha, touche

RXeligion

While I can see your point, I have filled it with about 900 lbs of grown men for a two hour commute (in reasonable comfort) on multiple occasions, so I would argue that it is. The seats in the back of my 8 are more comfortable than the seats in the back of my Hummer. IMO, I would say that the Panamera is the closest a company has come to duplicating the RX8 (because of their similar purposes and origins.)

Just my opinion, though.

Jeff77789

i would say as a passenger, i would much rather sit in the right seat farthest back with the seat in front moved all the way forward instead of the passenger seat in the front...just IMO, the back seats are much more comforter than the front ones

viprez586

iTrader: (5)

Honda hybrid's use 2 spark plugs per cylinder.

Station Equation

The advantages to the rotary engine are that they sound cool, and you never have to do a valve job or replace head gaskets.

The coming of cheap aluminum pretty much ended what packaging advantages that the rotary had. Physics and thermodynamics-wise, it's a lost cause. A cylindrical shape will always take better advantage of the dynamics of fuel ignition. And since the rotor face is larger than a piston face, you're going to lose more energy to heat loss. Other cars may choose to use two spark plugs for added efficiency, but the 13B NEEDS two plugs.

And the three moving parts thing needs to be re-thought. I used that one once in an argument, and got slapped down with this. "The rotary engine is three moving parts, two stationary parts, and 100 parts trying to seal the combustion chamber." He put the emphasis on "trying". In relation to the failure rates, while valves and springs are pretty robust, seals are not.

I love the rotary engine, but not because its necessarily better than the reciprocating engine. It's just neat. They solved the intake and exhaust timing issues of an internal combustion engine with GEOMETRY. Math works, folks.