http://www.mulsannescorner.com/news.html

I had heard a lot of rumors about next season 4 rotor engine but this is the firts time somobody working on it says it.

 

nice

 

engine swap :D

 

Drool

 

2 door coupe RX-8 whit that baby in it

 

SICK...

2 Door Convertible RX8 with 20B... Your hair will be pulled out by the wind...

:D

 

appears to still be a PP intake and exhaust, which is to be expected given the application.

I really want to see a 3 rotor side intake and exahust motor though, just be fun to see how much power and flexibility it has.

 

pretty neat, i think mazda would take what they have learned with the renesis 2rotor and use it in a 3 rotor version to power a RX7 or RX8 with more power before they went with a turbo/supercharger

 

I heard this engine was capeble of making 600 hp unristricted imagine what a 4 rotor can make

 

It is NOT a Renesis. It does share some parts with the Renesis though. It is not based on a Renesis and also not based on a 20B. It is basically a factory 13G 3 rotor race engine from the late 80's-early 90's. Why is it not a 20B? The 20B was never made in a peripheral intake port configuration. The 13G was never made in a side port configuration. The 13G is also 2" shorter in overall length than the 20B. It isn't because it is a Renesis though. The Renesis is just as long as a 13B. The 13G uses slightly thinner front, rear, and rear intermediate housings than the 20B. These corresponding housings are also shorter than their 13B/Renesis counterparts. The front intermediate housing is still the same width however as the 20B's at 80mm. The slight thickness savings over the 3 housings adds up to 2". The original 13G engine only had a compression ratio of 9.4:1 (or was it 9.7:1?). This is where the Renesis name comes into play. The Renesis rotors with their 10.0:1 compression ratio are installed in this engine. When they say that this engine benefits from the new metallurgy used in the Renesis seals, it is the literal truth. Only the Renesis seals fit in a Renesis rotor therefore you get their technology. The rotors and seals are the only things from a Renesis. That does not make this engine a Renesis though. A Renesis is an all side port engine. They also try to correlate the engine with the Renesis because it has the same eccentricity ratio and swept volume. All 13B's have these same numbers though so that is nothing new. This is a 13G engine using Renesis rotors.

 

we can have diferent opinions, to me a race rotary has to be a pp, what makes the engine its is internals, allmost all 13b shared the 4 side port intake an peripheral exhaust configuration but to me an early 13b and a series 6 13b-REW are diferent engines because of its internals ( rotor, compresion, seals, etc). just my opinion.

 

What are those plugged passages on the intermediate housings? And why is the front intermediate housing the same width as a 20B if this engine is full PP? Seems like there is extra weight there.

 

So the sticker on the engine was photchopped? Or is this truely a new engine labeled R20B?

 

on closer inspection it looks like a 20b side housing, I dit not notice that at firts, but it is been presented to the public as a new engine, then all this people are lying?

 

nobody has built a rotary like this one before so it is what they name it what it is is the new R-20b 3 rotor engine derived from the combination of 13g series of engines with some Renesis developement technology included.

 

The 13g nomenclature always seemed stupid to me, given that it was a 3-rotor.

 

zoom44:

I agreed wiht you.

 

I think 13g is confusing because rotary engine names are base on displacement, they could have call it a 20a or R20a.

 

The 13G was originally designed and built before the 20B. That's just the name they chose back then. It is a little misleading.

The blocked passages on the housings go into the sump system. They have no purpose. They are just leftovers from the molds in the casting process that get filled in with freeze plugs.

The R20B tags are just little plates with the letters handwritten on them and siliconed in place. It's a more appropriate name as the current race engines now use the prefix R to denote a race engine just as with the R26B engine. Of course R can now stand for Renesis also. 20B is also more appropriate due to displacement even though it shares no parts with the 20B.


The front intermediate housing is twice as thick due to the design of the eccentric shaft. There is a center bearing and stationary gear in this housing as well as the taper coupler for the 2 piece eccentric shaft. They needed the extra room. There are aftermarket 3 rotor kits that use equal sized intermediate housings and custom eccentric shafts which results in a shorter engine. The double wide center housing is probably a design holdover from one of the early 3 rotor experiments. The first ones literally had a front and rear housing from an engine modified and welded together. This resulted in a thicker plate. Since they aren't making anymore 3 rotor engines, they are using older parts. Mazda never made the equal sized intermediate housings. That's only an aftermarket thing.

 

So this is a PP, big deal. What's funny is how no one has pointed out that because they made this using Renesis rotors, this means that most internal dimensions would be Renesis-based. Would this mean that the eccentric shaft can be used in a real 3-rotor SP Renesis? There was a discussion here a long time ago that adding an extra rotor to the Renesis is possible, except there isn't an eccentric shaft created for that setup yet. Would this R20B be a good start to finally creating a 3-rotor Renesis?

 

The Renesis rotors are the same shape and size as all of the 13B rotors with the small exception of compression ratio which is determined by the size of the dish on the rotor face. The eccentric shaft is from a standard 13G as are all of the housings. It is literally just Renesis rotors and seals (which fit only into these rotors) installed in a pre-existing 13G race engine. Just a rotor swap.

 

Oh I see. So swapping rotors makes it a Renesis-based engine then? Why wouldn't they develop a SP 3-rotor engine RG? Is there an inherent problem to the SP design? I thought Mazda bragged that because of the SP design, the apex seals stay in tact in case of a knock or detonation much better than PP due to the lack of side ridges that might impact the apex seals' position.

 

Here's another piece of trivia for those of you who are interested. The 12A engines of 74 to 85 are actually 12B engines which denotes the changes in apex seal design and materials, the change from twin to single distributor and from top to bottom mounted starter location. 12B is Mazda's internal company code for this motor. The 26B and possibly also it's cousin the R26B carry the internal code 13J even though their housings have 13B written on them.

 

I also heard that the pp housings on this engine are made by CLR using its own desing ( for the peripheral intake), so this engine is a mixed of a lot of tecnology from diferent places , or does it use factory pp housings?

 

If they develop a 3 rotor side port engine it can be used on street cars and in clases like the gs in gran am, and the gt in speed series.