Mazmart

iTrader: (12)

I hope this truly warranted it's own thread as I thought it did. The moderators can decide.

Apart from the rotor housings being reduced in width (Front to back) perhaps to that of a 12A and the added stroke (Eccentricity) with the larger rotors, aluminum side housings, re-sized water passages (Perhaps), direct injection etc, etc, I noticed some very interesting things of note: The motor being displayed is a 4 port induction type for example.

More importantly,a major change I observed on the Aussie forum (That led to this thread) is what appears to be a relocated dowel. This dowel relocation is much more major than some may realize as it would facillitate an extra spark plug.

I could be wrong in my observation but I think the new housings may be cast with that potentially in mind.

I hope I'm right. Fred, feel free to chime in, and I hope others will make technical notes as we recieve more pics and info.

Paul.

Mazmart

iTrader: (12)

Here's the Aussie thread link with the excellent pics.


https://www.rx8club.com/australia-new-zealand-forum-37/renesis-16x-tokyo-motor-show-information-photos-129821/


Paul.

Renesis_8

Sorry Paul, I realize why you insist on the motor being a 4-port after I opened this thread.

Looking from the exterior of the motor, it sure is misleading. It looks like a 6port from the side until you crack it open.

Why do Mazda put those holes there tho? I am speculating that it is STILL a 6port design, 6 intake runners running into the engine, BUT those two ports on the side plates share the same intake port.
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Renesis_8

Assuming it has the same dimensions as the 13B. As stated before, they narrowed the coolage passage to make room for the displacement increase. Now, wouldn't cooling be an issue with decreased coolant passage area, then they'll need to up the coolant flow to keep up with the demand.

How is the water temp for 13B-MSP driven hard? Or they'll use more oil to cool the engine (3 holes per rotor), and maybe perhaps a really big oil cooler. Actually I like this idea, 2/3 cooling from coolant and the other 1/3 from oil. It is just like the racing rotaries.
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brillo

well, the center port is the same size as now, which sucks, but given the effort, I have to assume the tried a larger center housing and it just didnt add any material power.

Paul, I see your point about the spark plug, but why aren't we seeing it already with the prototype? figured that would be shown if it was the direct they are going.

Renesis_8

The 3rd spark plug could go right where the circle is above the dowel.

I think its for racing applications. If thats the case, they will make a peripheral port 16X or derivatives.

Or just in case they need the extra plug to meet future emissions.
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Renesis_8

It might look the same, but I think its actually bigger

Even if the area is the same as 13B-MSP, it could still flow the same at 7500rpm vs 9000rpm in a 13B.

The exhaust ports are definitely different! It almost looks like a ported exhaust port!



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CERAMICSEAL

Yep, she's definitely a 4 port ,aka low power version.

Seal.

Socr8tes

I believe the direct injection should result in lower operating temperatures.

John Corbitt

I think it is a 4 port. The port is a "bridge" port. The 6 port engines have 6 holes that can be controlled to work similar to variable valve timing in a piston engine.

gr8rx

couple questions for people that know?
1. why r the injectors located where they r and not closer to the plug, between plugs?
2 what is the rotor material? aluminum would be nice, titanium?
3. It looks like the combustion chamber is split into 2 chambers, r all rotaries like this, is this a new design? if so reasoning behind it?
4. it appears as if the 16x dish on the rotor face is longer, how will this affect combustion?

rotarygod

I disagree about it being a 4 port as I see signs it is a 6 port. Namely the additional outer runners although funny looking. The giveaway is on the computer screen that shows the exploded view. It shows a 6 port.

It is not a bridgeport. You will never see this. It's not even an option.

kartweb

As far as the rotor Aluminum won't work, Titanium would work but production capacity would be very limited. Thinwall ASTM A148 is the safest bet.

Regarding the injector and dish, several reasons. Some people might say the new layout allows for enough stratification of charge density to inhibit detonation. Other people would argue with that.

Oh yeah, don't be surprised if the friction coating in production looks a little more gold in color then silver.

raspyrx7

those holes above the spark plugs may be for knock sensors. With Direct injection, detonation will be very crucial as its the A/F is being mixed right before ignition. I wonder if they use a direct drive fuel pump like they do on the 2.3L disi?

DemonRX-8

The "split combustion chamber" is the result of the trochoid geometry, which creates the hump that seperates to two sides.

fmzambon

I'll throw here my comment.



This is probably the image that leads someone to state it's a 4 port engine.
Actually, the picture doesn't show the port/s on the end plate very well: it could be a single port or two very close ports. However, if those were wo distinct ports, they would be very small, only marginally bigger, when combined, than the primary port.
That would mean that the secondary port would be smaller than the primary port, which to me doesn't make sense.

The question remains about the extra hole in the end plate. I think there's a somple solution: couldn't it be that the holes are both machined/cast regardless of the version (4 vs 6 port), but then the aux. port itself is only opened in six port engines? This would explain everything IMHO. It would make the manufacturing process for both version more similar (reducing cost) and at the same time it would reduce the weight of the 4 port version.

About bridgeporting now:



Just follow the line formed by the housing / middle plate junction. This line is easily visible in the upper and lower parts of the engine. Following this line, it's possible to see that it passes between the primary port and the "bridgeport", a sure proof that the "bridgeport" is actually a reflection. By the way, a similar reflection is visible for the exhaust.

Finally the third spark plug: what about it being reserved for the six port engine, together with the aux port?

Just my 2.8 cents (nearly 2.9)

rotarygod

If you save that picture and zoom in, you can see it is a 6 port. The dividing wall is very tiny and hard to see.

There is no bridgeport. That is a reflection of the rotor dish. It's apparent shape is odd due to the way the chamber shape reflects it. It's a bit like a fun house mirror.

ASH8

Yes, I thought it was a 4 port, but, it is a 6..

Being a larger rotor with the larger stroke, I wonder when compared to the 13B what noise and vibration levels (if I can associate that word with a rotary) would be like, as the 16X has larger spinning mass.
More than likely very little, but the thought crossed my mind.

From close ups pics there appears no change in corner and apex seal design.
Having said that,?Are the 16X Apex seals slightly thicker (by say 0.5mm)?

I am still a little concerned at the length of the side seals.

BUT, IT IS A BONZA LOOKING MOTOR IN ALL CHROME!!! Isn't IT!

fmzambon

Tried that, but the picture gets too blurry to be sure.

INSANO FLEX

i wonder if it will be able to be bought as a crate and be put in the current rx-8

DMRH

I am impressed. Its a factory "Bridge port" engine. Although the "Bridged port" must be actuator controlled making it a 6-port bridge port...........lol

Those that know the non 13B-MSP ported engines will know that a bridge ported rotary breathes very well & makes excellent power, at the cost of a lumpy idle & fuel consumption but is mostly used for racing purposes anyway.

Years ago, Mazda actually stated that the 12A engine was the perfect dimesions for combustion & the 13B was a compromise.

Will be interesting to see the housing width (12A=70mm - 13B=80mm) when more technical specs are released.

REgards

8 Maniac

iTrader: (1)

if what I've read above is correct, it's not a bridgeport. and from what I can tell, I agree that it's not.

Jedi54

iTrader: (7)

great thread, I'll read up on it later and post some thoughts. (swamped at work)

fatmarco

What are the bits just inside(outside of chamber) of the ports? On some pics they are there, even on the exploded assembly? It looks like there might be a valve there, but on some pics there is nothing there. What is that???

Mazmart

iTrader: (12)

Here's one of the best pics showing it to be a 4 port.

Paul.