I am looking for a good 20B shaft to take measurement.

 

Royal waste of time.


-Ted

 

why? I want to make a better one. I work at a Machine Shop.

 

a 20b shaft is not the same as a short block renesis 3 Rotor engine shaft. The 3 rotor renesis has a shorter shaft compared to the 20b as theres no centre bearing plate

 

I think Guru already makes a short-version of a 3-rotor shaft that doesn't require the thick middle iron.

 

Really? Link?

I would have sent you a PM but no one replies to those on this board.

 

I was wrong, it's not Guru it is Kiwi-RE. I believe this is the kit:

http://www.kiwi-re.com/wwd_showroom_cat10_1.php

 

The Mutli-Side-Port design of the 13B-MSP (Renesis) with it's shared center exhaust port, doesn't lend itself to a triple rotor design, it baically requires rotor to be in pairs.

I know there are plenty of people here that know more about rotary engines than me, but here is a explaination of why a triple rotor renesis engine is a bad idea.
(complete with slapped together paint images to help).

This is the intake and exhaust port layout of a 13B-MSP (renesis) engine, I used a 4 port just to make life simplier, a 6 port only makes things worse in a triple rotor setup.




Below is the intake and exhaust port setup of a factory 20B triple rotor.




Now on to the fun stuff, with is the port layout of a short shaft triple rotor. note: this is a peripheral port engine, as retaining the side intake ports would leave the center rotor with less intake port area than the front and rear rotors.




Now for the ugly, this is a short shaft, renesis triple rotor, problem is the center rotor only has to smaller primary intake ports and two smaller secondary exhaust ports, so very restricted in both areas.



This design has been done, and I'm impressed that they made it work, but it still an example of how not to build a rotor engine in my book.



From looking at the image it appears they balanced the intake ports, by only used the primary and secondary but not the auxiliary ports in the front & rear housings of a 6 port renesis, and then they likely heavily ported the both primary ports leading to the center rotor to make up for that rotors lack of a larger secondary port. The Y shaped intakes and ITB are also probably there to make sure that all three rotors have a balanced air intake, a plenom setup would almost certainly result in a major inbalance in the air intake across the three rotors with this design.

For the exhaust I guess they ported the secondary exhaust ports either side of the center rotor to try and balance the exhaust ports across the whole engine, but I expect the center rotor is still exhaust restricted when compared to the other two rotors, also the shared secondary exhaust port of a renesis are design for rotors 180deg out of sinc, not the 120deg of seperation of a triple rotor e-shaft, so I expect there may be issues with the exhaust pulses passing bewteen rotors.


Final there is the expensive option, this is a triple rotor renesis engine layout using a 20b e-shaft, and a custom made thick center plate.



Problem here is one cost, you need to have a custom thinck center plate made that has both side intake and exhaust ports, this would have to be designed from scratch and then either made using a very complex cast or as two cnc billet items that sandwedge together to make a single plate, this is the only way to retain the internal water passages. the second issue is while this solve the intake port issue the same way the stock 20b engine does, it doesn't solve the problem of the miss-matched number of secondary exhaust ports and the 120deg exhaust pulse issue.


A quad rotor regesis engine could work and is more pratical if your going to spend the kind of money needed to produce the option above, but the problem is with the need for a custom center plate around 4" thick to house two secondary intake ports and two primary exhaust ports such an engine would need, it would end up being almost 3" longer than the current batch of peripheral port quad rotors.

I sure others will have a different take on what I've said, but basically a triple rotor MSP rotary is a bad idea, possible to build but in no way is a pratical option.

 

One helluva explanation!

Summation?
It's a royal waste of time.
You guys gotta get your heads out of your *** to think the Renesis engine is a much better engine than the earlier 13B (with peripheral exhaust port) design.
It's inferior in terms of all-out power.
Sorry to burst your bubble.

If you're building a 3 rotor for better emissions, then I can understand...which, in itself, is a royal waste of time.


-Ted

 

I see what you are saying with regard to the intake pluses. I wanting one to record all the features of it's and design, and make it better and make a 4 or 3 rotor engine. I would like to make my design more cost effective so more people could have them I work at a machine shop and have access to mills, lathes, abrasive waterjet, etc.. I also have Solidworks to do all the design to make the parts. I would like to make one for a street ride of mine. You can make more power if you have the design, and can tweak it. The renenis is a more powerful design when you tweak the intake track. Mazda could of made it more powerful but had size, cost, emissions, etc.. to keep them from making it more powerful. I will also be making a model for the rotor housings, to investigate direct injection. make it possible if or when Mazda comes out with 16X engine. Just doing some research to make the design possible. I know that rotary engines are complicated, but can be improved by someone who want to make it better and will devote the time. I will leave the stuff like rotors and seals, etc.. to Mazda.

 

Ha Guthrie,

If you've got the time, the skills and the equipment go for it, if you want to play around with direct injection you should see if you can source a set of 13B-DI rotor housing from japan, as used in the RX8 Hydrogen RE and the SENKU concept car, basically renesis rotor housing with direct injection ports.

The 13B-MSP solved the emission issues of 13B-REW but really didn't push the design, the 16X design looks to be a lot more optimised for the MSP configuration, and with direct inject and an all aluminum block it looks like a much bigger leap forward than the Renesis was.

The 16X with it's thinner 70mm rotors also opens the door to a truely streetable quad rotor engine, a 32X would need a custom 4" center plate and center bearing 3 peice e-shaft, but would only be about a 1" longer than a peripheral port quad rotor, but without the noise, weight and idling issues.

A naturally aspirated 32X engine would offer up a light (Probably not much more than a 13-REW including turbos & stock manifold), powerful (a good guess would be 500-600 BHP), high torgue (four rotors and the larger rotor radius will do that for you), relatively fuel efficient for an engine of it size and power (a 600HP 3.2litre rotary is never going to go easy on the gas bill), option for those that want more power without the weight, complexity, and reliablity issues of a traditional big HP rotary engine.

I look forward to seeing the day this is possible.

 

No, it's not.
The BHP numbers you see printed for the RX-8 is due to:
*increase compression on rotors
*"scalloped" rotors
*increased redline
*3-stage intake system

I don't call it a "tweak".
I call it an all-out revision!

Strip all the OEM crap out of the engines, and the older rotary engines with peripheral exhaust ports will always win versus any Renesis MSP (exhaust ports).

Mazda has always claimed the peripheral exhaust port will have more power potential than any MSP.
If you don't believe me, do read all the SAE papers on this subject.
http://www.sae.org/

Please stop spreading myths.


-Ted

 

I never claimed that the renesis is the more powerful than a P exhaust port. There is a reason Mazda is going down this route and it is not just emissions. There is something to be said for usable Torque for the street. It might make more power, but I was talking about making the renesis motor more optimized and the 16X when it comes out. I am not spreading myths. I am just trying to make something good even better. I also think that a engine with DI will be more fuel friendly. Thank you to all who want to help me.

 

I just need to remind you of what you did type:
So may I ask what were you trying to say?
If you're comparing the Renesis to any prior rotary engine, they are all either peripheral port exhaust or both peripheral intake and exhaust ports.
Are you trying to compare the Renesis to a piston engine?


Mazda did design the Renesis MSP motor primarily for emissions, period.
I'd like to see evidence to prove otherwise?
The above point is repeated over and over in SAE papers.


Define "usable torque"?
Are you talking about a fully laden engine with OEM emissions and controls?
I thought we were talking about a highly modified engine here...
Most of us are going with turbos, so mentioning anything normally aspirated doesn't apply.


Most of the points you just have mentioned do not exist as a production engine as of this point in time.
Thus, you're talking about a truly custom, one-off engine.
Why would you need to take measurements of existing engine components when such an application does not exhaust when it comes down to the 16X engine and direct injection?

I'd like to really see you pull this off...or blowing smoke up our asses.


-Ted

 

A lot of the feature of the shaft will be the same, but some will be different. I was talking about the exhaust being like older engines. I am talking about making a engine that is a N/A engine, but could be used as a turbo engine. Turbo engines are much easier to do than N/A when it comes to getting more power. One example is that the taper on a 20B shaft will be very similar. I was saying that the renesis intake profile is larger than previous engines and the renesis has twice as much exhaust port area. When I get a shaft I will be able to get closer to it. Also be getting a renesis center housing for inspection and protype a new housing.

 

I think there is potential for the p-port concept. use 9.7 rotors and see how thin you can make the side plates as they no longer have to support the intake ports. You'd basically need enough volume for coolant and oil flow and that's it. I think you could cut the length of a 20B down quite a bit with a custom E-shaft custom side plates.

-Trent

 

TAZ,
"Now on to the fun stuff, with is the port layout of a short shaft triple rotor. note: this is a peripheral port engine, as retaining the side intake ports would leave the center rotor with less intake port area than the front and rear rotors"

Is it possible to use the OEM 20b UIM with a custom lower with this configuration?(short shaft PP 3 rotor)