these days you can buy pretty much every part custom made for a 13b .......what im wondering is how come i don't see anyone with a 2l or 3l or even a 4l two rotor engine? 13b's are impressive but what would a 4 liter do?
how much power would it make??

im not saying a street engine ....as a drag engine it would be insane .

just my thoughts

any ideas? pros cons?

what size turbo would it need ...haha

 

Go to mazda.com Look at the 16x, i cant wait.

 

i read up on it a bit ago ....all i can say is it looks impressive and i hope they make a option where you can just buy the engine and the dealer can keep the shell .....haha
im going to be test driving that straight away ....for sure

but come on someone say that they are making a 5 liter two rotor ........thats all i want to hear .....and post some pics !

but seriously someone with the resources should build one .I plan one day in the future when i have the money and time to attempt something like this

also how come i dont see any titanium rotors??!? i know it would cost a lot for the material and the machining will take along time ,but wouldn't that be something else ?

i keep wishing that ill somehow ill get 10 million bucks so i can stop working and make my 100% titanium 13b but its a long shot ...haha

but someone should make a set of titanium rotors for the 13b!!!

 

Your a little bit away from that. Aluminum rotors haven't even been around very long and their for the real performance seekers at 2KUSD a set for a 2 rotor. And the problem isnt with the rotors being strong. They need to be lighter.

 

^Iv'e seen those billet rotors, very impressive. But not worth 2k for me. They should use that design in the new 16x!

 

the 16x is claimed to be a full aluminum external block. That would be one hell of a light motor. I don't think you would even need a lift to put it in the car at that point.

I mean were talking about a 150lb max block...

 

all it needs is a nice peri-port exhaust.

 

I wholeheartedly agree with a weight reduction; however, I don't think aluminum is the material of choice for general purpose applications. The rotors also need to less thermally conductive and have a lower specific heat--both qualities that Aluminum does not posses. The result is more heat pulled away from the combustion chamber, thus further lowering the thermodynamic efficiency of the motor. And more hot oil to cool. A thermal barrier coating might help mitigate this. Except for its weight, cast iron actually offers some pretty good properties.

Which leads me to this thought.... The general obsession with weight in engines has resulted in materials that lower thermodynamic efficiencies (and reduce power). And there are many economic considerations that drive the use of aluminum in engines, as opposed to weight. I think that rotary motors would benefit from having a thin cast iron liner or sleeve pressed in the rotor housing for its wear surface (rather than the chrome plated aluminum), not unlike what is used in aluminum block piston engines. It would certainly be more efficient for a minimal weight increase and potentially solve several problems. My guess is that the economics does not favor this as practical. However, if one can keep more heat in the chamber where it belongs, then some of the rotary's drawbacks can be tempered.

A longer stroke in the rotary could also improve its equivalent "rod ratio" by increasing the leverage available for the combustion gases to act upon. If this is the case, then torque (and especially low end torque), could be significantly improved beyond the simple increase in displacement.

 

Although I get your point and you are accurate on some of your thermodynamic "guessing" of materials in general, You are incorrect in stating that MAZDA uses "chrome plated aluminum" rotor housings. They have a STEEL liner that is chromed plated fixed within the aluminum rotor housings.

This has already been addressed with the new 16X. The entire purpose of the engine was to increase the effective stroke of the eccentric shaft thus improving low end torque and drivability. The result of course was a bump in displacement (shape of the rotor having a longer stroke of course means a larger rotor). Another tid bit added to increase efficiency was to make the combustion chamber narrower, effectively making the swept volume ratio less then previously with the 13b.

Are you a rotary guy at all? No offense but you sound like a piston guy who happened to come across our little rotary forum and your throwing in your $0.02, which is good ideas, just decades behind what MAZDA has already done.

~Mike..........

 

Increasing the stroke of the engine is the only good way to do it. I often commented in the past that the 13B width was too wide, hence the bowing of the apex seals. the 12a, and 10a engines rarely twisted their apex seals when the detonated, and before you comment, realise that there have been some real heavy duty 12a turbos built over the years, especially here in japan. Mazda realised that they had hit the point of diminishing returns as far as increasing the width of the rotor went, hence the longer stroke this time.

 

I hear the 16x rotor is the same width as the 12a, narrower than a 13b and still gets more displacement with the longer stroke! Just think if the 16x rotor was as wide as a 13b... Maybe that will be the new 18x.

 

i just cant wait to make my very own 32x.

 

but i would still like to see a 13b scaled up to ...say a 3liter or 4 liter .....just as a drag racing engine .

and the 16x looks nice but its going to be a fight at the junk yards to get your hands on one from a crashed rx8......

as bad as this is going to sound ......and its bad ,i might have to go test drive one to crash it .....haha

 

There's a big leap between reverse engineering a factory component and making something just like it, but slightly changed and engineering a complete new engine. Besides, as far as I'm aware you can't get custom rotor housings or stat gears that aren't just worked over factory parts to name two. So you can't get everything custom, but yes, there is a lot you can get. It'd be a lot cheaper to simply swap in a 20B or even build a 26B probably. I'm not saying that it can't be done, just that it'll be difficult and VERY expensive.

 

I think the view that his looking at things at is by elongating the the chambers futher more which means longer seals, and they would be easier to break.

I really can't wait till there's a few companies around the world that build them from scratch like you can build a V8 engine from scratch though. Perhaps another 30 - 40 years before that happens when the rotary engine would have reached the same time that the piston engine has been around.

 

This may sound completely stupid, but I slipped getting out of the shower this morning and something popped into my mind. Since its a round (or bathtub as it likes to be called) combustion chamber, couldn't our motors be made electromagnetic? Similar to brushless systems just on a much larger scale? Unless im mistaken, this would get rid of the need for apex seals, the main weak point of our motors.

 

True rotorhead

 

no i mean scale it up ......just like a scaled up model . yes the seals would be longer but they also would be thicker and taller so i dont think breaking would be much of a huge problem as fuel consumption .

my idea has already been done.....ive seen pictures of (dont quote me ) curtis wright .in the picture they have a 13b rotor and two or three larger rotors and there is one that looks like its two or 3 feet tall .

but the main draw back that i see is lining the rotor housings ....but i did see someone who was setting up and re chroming old 12a housings.....all you would need is some sort of press in sleeve.

i have a decently sized machine shop but in no way do i have the time or money to stop working one day i hope to try it

what size of a turbo do you think a 4l two rotor would need ?haha

 

Everything you are talking about has been done. Just not on rx7club. Look in the back of the Rotary engine book by kenichi yamamoto. There have been rotaries that are very large. You just need to do some research.

 

I believe Ingersol Rand had a single rotor rotary that was 52 ft(?) in diameter. Not 100% on the number, it was large tho

 

pics or it didn't happen.

 

it would have been helpful if Corvette and GM had continued on a 4 rotor rotary 1973, specs were like 3-4 liters of swept volume.
but 1st oil crunch hit, and OPEC was formed, so as usual, they stopped all R&D, because emissions and fuel price doubled in 3months, and stayed there.

but **** happens!! OH WELL

 

and with the 13b , i dont think we are gonna see any miracles in performance , more than whats out there now.

 

http://cp_www.tripod.com/rotary/images/pg08_01b.jpg

here is the pic that i remembered seeing ....and yeah ill have to agree with you that the 13b is almost at its peak in the performance level.

but i wanna see a bigger two rotor that can compete with top fuel rails ...its possible just hope fully it isnt in 30 some plus years .

 

and the rotor in the pic was for a single rotor engine and its a 1920 cubic inch rotor.