the shorter seal height could also be used for sprung weight reduction...?

Shorter seal height makes me think they could have tweaked the eccentricity of the housing for less seal travel and less groove wear.

The new 2 piece seal that replaces the 3 piece, will it seal as well?

Uh. no. I used to think that too, but after researching the issue it turns out that the engine runs too rough on only one rotor. Not a problem in a car, but in an airplane the vibrations are amplified by the propeller to the point where things start flying off the plane if rpms are kept up too high.
Since a two-rotor engine operating on only one rotor only produces about 35% power, throttling back to decrease the vibes will leave you with not enough power to maintain altitude. This will increase your glide distance, but if there's no landing strip within gliding distance you'll be doing an off-airport landing.
This actually happened about 8 weeks ago to a guy named Chuck Dunlap. He was on his way to Arlington Wa. in his 13B-powered RV6 kitplane. While over the grand canyon a dowel pin in the Pinneapple racing-supplied secondary intake actuator worked loose and was ingested by the engine. This destroyed his rotor and housing.
He was able to glide to a hwy and make an emergency landing, but a truck got in his way and in avoiding a collision his landing was rough enough to slightly damage one wingtip.
It's true that if these engines overheat they won't seize, which is good in aircraft. But the engine will need to be replaced after landing.
The only other failure modes are fuel starvation, electrical failure, and apex seal failure. As long as you don't overboost them and as long as you run premix instead of that crud from the oil pan to lube the apex seals (and don't ingest any foriegn object debris) the apex seals will hold up just fine.

yup
thats what they did since the 8 has a higher redline

Ha ha, "crud from the oil pan", perfect way to say it. I knew the aviation rotary engine builders disabled the crankcase oil injection! Crud is right. When that stuff burns, it leaves behind all the dirt and acid held in suspension, which cakes the rotor with soot. "Hot spots", anyone?

Some of the second gen guys don't agree.

i really wanna see the testings of mazdatrix and know if they will work in the other 13Bs

\
they will if you machine the apex seal slots

????

while its far from conclusive the factory used a metering pump on the 787's

mike

They also had 3-piece ceramic apex seals and the engines were torn down after every race...

maybe it was a rule thing?

As long as there is enough casting(material) around the apex groove left after milling to accomodate the regular height seals they should work fine in earlier motors. Can't wait to see the results from Dave at Mazdatrix.

hey i got the new 2pc mazda seals in my engine and my compression SUCKS! =(

Alum. rotor
 

I am no engineer but I would imagine it would be pretty hard or costly to have a bearing and a pressed in gear in the center of a piece of alum. Not to mention all the seal groves have to resist to wear. Piston rings barely move in ring grooves compared to an apex seal. The rotor gear is pressed for vibration dampening so with alum. rotor may be the vibration will be an issue again. Pressure on a piston I would think is pretty even across, but on a rotor I would think it is about as uneven as you can get. Gasoline motor all have prtty much same temp. but the reason for rotaries and two stroke to have higher exhaust temp AT THE MANIFOLD is because there are no valves or runners in a cylinder head to soak up the heat. Contrary to a Porsche owner's belief rotary does not run hotter, the exhaust just done not get cooled as much. The combustion temp. I would think is higher in a piston motor because of better thermal efficiency.

Oh I forgot to mention the teflon piston that has been under developement for years now. May be rotary can skip alum. and go straight to teflon in the future. :)

or ceramic~ *#&$@!!

or ceramic~ *#&$@!!

Wasn't it the Vega that had a teflon cylinder walls?

The ones that everyone had bored out to build monster vegas w/ stock motors (not talking about BBC Vegas) because the teflon had a tendency to chip off and trash motors... At least that's what memory tells me.

and then put back together because there was barely measuable wear

The point could be made that more than likely Mazda had whichever oil company was sponsoring them brew up a special blend of oil specificially for that motor which would eliminate any problems of injecting motor oil into the engine... ;)

if there are any in the first place

What do you mean if there are any in the first place? Oil company sponsors? Don't be silly, of course there is. Renown Petroleum Ltd. which has, it seems, has since gone away. Look at the front and sides of the car. ;)

Oh, that. My bad.