renesis porting...different.
07-08-08, 04:05 AM
#26
before i actually open the motor up, im going to get it running in the car so i can have it tuned and dynoed. this way when i open it up and port it, i can see what the actual difference is.
im in the process of making my own oil pan, and designing the intake manifold. this will take a little time. the only thing stock is the core. as i get things done. i will be posting them up...
im in the process of making my own oil pan, and designing the intake manifold. this will take a little time. the only thing stock is the core. as i get things done. i will be posting them up...
07-14-08, 10:05 AM
#27
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Rotarygod,
I was going to PM you but I have to do this 3 post rule bs so i guess i'll just throw it up here.
Hello Rotarygod,
I am new to this site but not to cars. I am a vehicle calibration engineer for Delphi. I just bought a 1982 startlet and have decided that a rotary engine in it would be the best setup overall and the Renesis has me most intersted. I figured getting an engine and tranny combo in my car to start with an do an aftermarket ecu with a manual throttle would be the easiest way to get around all of the emmisions junk along with all of the electronic trickery that only would apply to an calibrated RX-8 vehicle since in New York State my car is exempt because of its age. My end goal is to design a 3 rotor version of a RX-8 engine in hopes of getting roughly 375hp and 250 ft-lbs in a 2100lbs car. After a couple conversations with Dave Lemon of Maxdatrix is seems that all of the old stuff is dying off since it is getting increasingly hard to come by irons and such in good condition so I felt the Renesis would be a better base to build on.
I would be intersted in seeing your dyno graphs of the torque and hp curves for the mods you described. It seems to me that looking at some of your posts that you have dumped some time into development of this engine and I would like get a feeling for where you are and where you plan to go with all of it.
Rob Woods
I was going to PM you but I have to do this 3 post rule bs so i guess i'll just throw it up here.
Hello Rotarygod,
I am new to this site but not to cars. I am a vehicle calibration engineer for Delphi. I just bought a 1982 startlet and have decided that a rotary engine in it would be the best setup overall and the Renesis has me most intersted. I figured getting an engine and tranny combo in my car to start with an do an aftermarket ecu with a manual throttle would be the easiest way to get around all of the emmisions junk along with all of the electronic trickery that only would apply to an calibrated RX-8 vehicle since in New York State my car is exempt because of its age. My end goal is to design a 3 rotor version of a RX-8 engine in hopes of getting roughly 375hp and 250 ft-lbs in a 2100lbs car. After a couple conversations with Dave Lemon of Maxdatrix is seems that all of the old stuff is dying off since it is getting increasingly hard to come by irons and such in good condition so I felt the Renesis would be a better base to build on.
I would be intersted in seeing your dyno graphs of the torque and hp curves for the mods you described. It seems to me that looking at some of your posts that you have dumped some time into development of this engine and I would like get a feeling for where you are and where you plan to go with all of it.
Rob Woods
07-15-08, 12:34 PM
#29
I have some other ideas for the Renesis but I have no idea when I'll get around to trying them. I've already ruined 1 housing playing around. They are still pretty expensive to just sacrifice in the name of science.
It wasn't my car that had the ported Renesis. It was a guy on the RX-8 forum. It's pretty well known who's engine it was. It's his dyno chart and he has opted not to post it online as he doesn't want people to sit there are try to criticize it as is usually the case. This thread is even the first time I've ever mentioned his results publicly.
There isn't a whole lot that you can do to the engine easily. I'd like to see some things done differently but the water jacket is in the way and from trials so far, welding those housings back up has proven to be a nightmare. Once I get that perfected, then I'll really start having some fun! I would like to see some different exhaust configurations tried as well but as of yet no one has tried any of them.
A 3 rotor Renesis has been built and run. The owner likes it and says it makes good power. However this doesn't mean it's optimal. The siamesed center port flows like crap. If you build a 3 rotor Renesis, you have a center rotor that is only breathing through 2 siamese ports. This means the center rotor will never make the same power the others do so it'll always be off. It's not to say the engine doesn't run and make decent power but I'm very picky when it comes to things like this. If I can figure out a way to get the exhaust port issues taken care of, it may have potential.
The Renesis is my personal engine pick over all of the other 2 rotor engines out there. Many people still swear by the 13B and chastise the Renesis but that's like criticizing the modern Chevy LS series V8's in favor of the old L98's. The Renesis is a much better engine overall if you know what you are doing.
It wasn't my car that had the ported Renesis. It was a guy on the RX-8 forum. It's pretty well known who's engine it was. It's his dyno chart and he has opted not to post it online as he doesn't want people to sit there are try to criticize it as is usually the case. This thread is even the first time I've ever mentioned his results publicly.
There isn't a whole lot that you can do to the engine easily. I'd like to see some things done differently but the water jacket is in the way and from trials so far, welding those housings back up has proven to be a nightmare. Once I get that perfected, then I'll really start having some fun! I would like to see some different exhaust configurations tried as well but as of yet no one has tried any of them.
A 3 rotor Renesis has been built and run. The owner likes it and says it makes good power. However this doesn't mean it's optimal. The siamesed center port flows like crap. If you build a 3 rotor Renesis, you have a center rotor that is only breathing through 2 siamese ports. This means the center rotor will never make the same power the others do so it'll always be off. It's not to say the engine doesn't run and make decent power but I'm very picky when it comes to things like this. If I can figure out a way to get the exhaust port issues taken care of, it may have potential.
The Renesis is my personal engine pick over all of the other 2 rotor engines out there. Many people still swear by the 13B and chastise the Renesis but that's like criticizing the modern Chevy LS series V8's in favor of the old L98's. The Renesis is a much better engine overall if you know what you are doing.
07-20-08, 01:28 PM
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Rotarygod,
I found the 3 rotor you were speaking of and I also came across the 60 page post that you referred to and you reluctance to post graphs and info. The engine was pretty cool but it does bring up the issue of port symmetry which you called into question. I have built all sorts of cars from drag cars to Formula SAE cars and I am notorious for symmetrical design and thinking so I hear you on that.
I am assuming that Mazda built the port without symmetry for reason of full range driveability since they stage the ports on the 6 port. Do they stage ports on the 4 port versions of 13B and the 20B? I was looking at build of a 20B and I don't see any kind of shutter valves for the secondary pipes so I just assume they toggle the fuel at a certain point? Why would they build this flow and fueling imbalance into the engine on purpose?
In a world which we speak of where we are concerned with performance(i.e mid to upper rpm with lots of throttle) I would imagine we would want symmetrical port setups on the car. That would go as well for the aerospace guys who just run at constant rpm who could tune the engine to run where they want rpm vs flow wise. This would obviously require newly designed side housings which in reality are not too hard to design however the cost involved for the average person would be way too high to take on. Thoughts?
I found the 3 rotor you were speaking of and I also came across the 60 page post that you referred to and you reluctance to post graphs and info. The engine was pretty cool but it does bring up the issue of port symmetry which you called into question. I have built all sorts of cars from drag cars to Formula SAE cars and I am notorious for symmetrical design and thinking so I hear you on that.
I am assuming that Mazda built the port without symmetry for reason of full range driveability since they stage the ports on the 6 port. Do they stage ports on the 4 port versions of 13B and the 20B? I was looking at build of a 20B and I don't see any kind of shutter valves for the secondary pipes so I just assume they toggle the fuel at a certain point? Why would they build this flow and fueling imbalance into the engine on purpose?
In a world which we speak of where we are concerned with performance(i.e mid to upper rpm with lots of throttle) I would imagine we would want symmetrical port setups on the car. That would go as well for the aerospace guys who just run at constant rpm who could tune the engine to run where they want rpm vs flow wise. This would obviously require newly designed side housings which in reality are not too hard to design however the cost involved for the average person would be way too high to take on. Thoughts?
07-22-08, 12:22 PM
#31
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for the real 3 rotors mazda cast center housings with different ports so that the rotors do have symetrical ports.
the renesis 3 rotor is just using 2 rotor parts, and thus isnt symetrical. only way to make it, is either to cast your own, or wait for mazda to maybe make one.
the renesis 3 rotor is just using 2 rotor parts, and thus isnt symetrical. only way to make it, is either to cast your own, or wait for mazda to maybe make one.
07-22-08, 10:07 PM
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for the real 3 rotors mazda cast center housings with different ports so that the rotors do have symetrical ports.
the renesis 3 rotor is just using 2 rotor parts, and thus isnt symetrical. only way to make it, is either to cast your own, or wait for mazda to maybe make one.
the renesis 3 rotor is just using 2 rotor parts, and thus isnt symetrical. only way to make it, is either to cast your own, or wait for mazda to maybe make one.
When I look at pics of a 20B or a 13B for that matter not only does the port timing appear to different but the port size, is massively different. I understand it is balanced in the sense that each rotor has equal primary and secondary ports. What I am questioning is that the difference in these ports and also how they don't seem to have any kind of deactivation valves like on a 6 port renesis.
07-23-08, 03:42 PM
#33
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When I look at pics of a 20B or a 13B for that matter not only does the port timing appear to different but the port size, is massively different. I understand it is balanced in the sense that each rotor has equal primary and secondary ports. What I am questioning is that the difference in these ports and also how they don't seem to have any kind of deactivation valves like on a 6 port renesis.
the early engines are pretty symetrical in port size, they have to strike a balance between low rpm power, and high rpm power.
in the early 80's they solved that problem 2 ways. the turbo engines keep the "4port" setup, and add the turbo.
the non turbo engines add an extra port to become 6 ports. it works like the 4 port carb engines, but with another step, so it has more power down low and up high.
the 20B-REW engine as delivered by mazda for the cosmo, is setup to haul a big automatic coupe around. so its got small primary ports, and large secondary ones, to keep some midrange power. and the turbos are sized on the small side
07-24-08, 08:00 AM
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You are correct about the carburator/throttle body. I totally forgot about that. My dumbass oversite. Going back to port symmetry my question still exisits about making the primary and secondary ports the same on a 4 port design.
07-24-08, 11:44 PM
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the only real impediment to doing it in a fuel injected engine, is the casting isnt there to go that big.
other than that, you just loose sub 2000rpm torque, and in a car with small tires and 4:1 gears, you just dont spend a lot of time there
06-11-14, 04:52 PM
#38
lol... Nope. I just didnt see the value in doing it. I have a problem with having to many projects and not enough money.
I see much more potential in using gslse housings and a semi-PP 4 port renesis. that's my next go to.
I did this instead. but still plan to do the sem-PP 4 port reness after this one is complete.
I see much more potential in using gslse housings and a semi-PP 4 port renesis. that's my next go to.
I did this instead. but still plan to do the sem-PP 4 port reness after this one is complete.
06-12-14, 10:40 AM
#40
The housings posted above will be for a slide throttle, Semi-Direct injection, e85, PP Renesis going into my Rx2. Not looking for any kind of secret power potential here. Just having fun doing something slightly different.
I have debated back and forth about using the gslse housings instead, but I would like to see what I can do with all renesis parts first.
I have debated back and forth about using the gslse housings instead, but I would like to see what I can do with all renesis parts first.
06-12-14, 03:41 PM
#41
well, you're probably right about using the MSP parts first. at least, that's the way i see it. in the event that things go awry, it's better to FUBAR Renesis rotor housings than SE ones.
that said, your plans sound cool. any grassroots DI rotary project (semi or otherwise) deserves respect in my book. i look forward to seeing how you go about building yours.
that said, your plans sound cool. any grassroots DI rotary project (semi or otherwise) deserves respect in my book. i look forward to seeing how you go about building yours.
06-13-14, 09:17 AM
#42
Can you improve it? Yes. How much is the real question. The 4 port Renesis engines have smaller exhaust ports than the 6 port engines. They close 10 degrees sooner. You can probably touch them slightly. 10 degrees on the closing side really isn't much at all and you need to be careful that you've still got enough material to support the corner and side seals as they go by.
The primary intake ports on the 4 port also close 10 degrees earlier. The primaries are the one place that you can do alot too. This is where most of my porting work was done. You'll look at the runner to port transition and see a wall where the runner goes behind the port. It's cast this way. It looks like crap and is terrible for flow but it was intentional. You'll see what I mean when you get one taken apart. The runner goes under the oil seal track a little bit. The port opening does not. Do not try to open the port up to match this! I actually cleaned it, roughed it up really well, and then filled it in and reshaped it out of epoxy. If epoxy makes you nervous don't try this. If you are careful and know what you are doing it can be completely reliable. You hear horror stories of epoxy from people who didn't do it right. Anyways, this lip is called the AWP or anti wet port. It is purposely done this way to induce turbulence at the port mouth. This turbulence may be bad for flow but it helps atomize the fuel better. This works in conjunction with the injectors being pointed straight at them as opposed to straight down and with some small air bleeds that go into the lower manifold and into the runners. I got rid of it all.
The secondary ports are where you are trying to concentrate your porting on. The secondary ports close later by 10 degrees than the secondaries on the 6 port although you don't have the auxiliary ports to work with. The castings are "supposedly" the same but I'm not entirely sure. I've seen dumber things. Be very careful. Check the thickness of the castings very closely. You may or may not be able to do what you think you can. The water jacket location on the Renesis is very odd. Just to give you an idea, if you tried to bridgeport the exhaust ports, you'd hit the water jacket! It's hard to envision so just trust me. You'll see what I mean when you get it.
I'd buy some new oversized side seals from Mazdatrix. You will have to clearance these on your own. You may have seen the many threads on the forum about side seals clearances. Some people like running "zero clearance". I measured clearances 4 to 5 times greater than the MAX clearance specified on the 13B;s from Mazda. You do need more clearance due to seal expansion from the heat of the side exhaust port but that's ridiculous! Use the high end of the factory specs for the 13B. The number just happened to escape me at the moment but it's easy to find.
Whatever you do, ALWAYS premix on a Renesis! I mean that for everyone who owns a pre 09 model RX-8 too. Mazda messed up with the oil metering system and it is why so many of those engines have been dying. They have 2 oil metering jets per rotor. Nothing out of the ordinary there. They are both on the rotor housings now though instead of just 1 per rotor on the housings. They are pointed towards the corners of the housings though as they are trying to get oil to the corner seals now. This leaves the center of the apex seal inadequately lubricated though. If you could see a chart of seal temperatures you'd see that the center of the apex seal gets hottest. That's where the oil metering is most important. This is the area of least lubrication on the Renesis. Seals warp, compression goes down, wear increases. This explains everything from inconsistent dyno numbers on RX-8's, low power numbers, and even explains why Mazda has gone through so many ecu reflashes on the car. They figured it out through and the 09 model cars now have a 3rd oil injector per rotor! Mazda knows they messed up as they've extended the engine warranty on all RX-8's to 100K miles. It's retroactive for those who had already had their warranties expire. Mazda has not publicly admitted that the oil metering was flawed in design. They are just fixing the issue slowly and are trying to be quiet about it. Some of us figured it out though! Use premix!
If you ever have any other Renesis questions, just ask.
The primary intake ports on the 4 port also close 10 degrees earlier. The primaries are the one place that you can do alot too. This is where most of my porting work was done. You'll look at the runner to port transition and see a wall where the runner goes behind the port. It's cast this way. It looks like crap and is terrible for flow but it was intentional. You'll see what I mean when you get one taken apart. The runner goes under the oil seal track a little bit. The port opening does not. Do not try to open the port up to match this! I actually cleaned it, roughed it up really well, and then filled it in and reshaped it out of epoxy. If epoxy makes you nervous don't try this. If you are careful and know what you are doing it can be completely reliable. You hear horror stories of epoxy from people who didn't do it right. Anyways, this lip is called the AWP or anti wet port. It is purposely done this way to induce turbulence at the port mouth. This turbulence may be bad for flow but it helps atomize the fuel better. This works in conjunction with the injectors being pointed straight at them as opposed to straight down and with some small air bleeds that go into the lower manifold and into the runners. I got rid of it all.
The secondary ports are where you are trying to concentrate your porting on. The secondary ports close later by 10 degrees than the secondaries on the 6 port although you don't have the auxiliary ports to work with. The castings are "supposedly" the same but I'm not entirely sure. I've seen dumber things. Be very careful. Check the thickness of the castings very closely. You may or may not be able to do what you think you can. The water jacket location on the Renesis is very odd. Just to give you an idea, if you tried to bridgeport the exhaust ports, you'd hit the water jacket! It's hard to envision so just trust me. You'll see what I mean when you get it.
I'd buy some new oversized side seals from Mazdatrix. You will have to clearance these on your own. You may have seen the many threads on the forum about side seals clearances. Some people like running "zero clearance". I measured clearances 4 to 5 times greater than the MAX clearance specified on the 13B;s from Mazda. You do need more clearance due to seal expansion from the heat of the side exhaust port but that's ridiculous! Use the high end of the factory specs for the 13B. The number just happened to escape me at the moment but it's easy to find.
Whatever you do, ALWAYS premix on a Renesis! I mean that for everyone who owns a pre 09 model RX-8 too. Mazda messed up with the oil metering system and it is why so many of those engines have been dying. They have 2 oil metering jets per rotor. Nothing out of the ordinary there. They are both on the rotor housings now though instead of just 1 per rotor on the housings. They are pointed towards the corners of the housings though as they are trying to get oil to the corner seals now. This leaves the center of the apex seal inadequately lubricated though. If you could see a chart of seal temperatures you'd see that the center of the apex seal gets hottest. That's where the oil metering is most important. This is the area of least lubrication on the Renesis. Seals warp, compression goes down, wear increases. This explains everything from inconsistent dyno numbers on RX-8's, low power numbers, and even explains why Mazda has gone through so many ecu reflashes on the car. They figured it out through and the 09 model cars now have a 3rd oil injector per rotor! Mazda knows they messed up as they've extended the engine warranty on all RX-8's to 100K miles. It's retroactive for those who had already had their warranties expire. Mazda has not publicly admitted that the oil metering was flawed in design. They are just fixing the issue slowly and are trying to be quiet about it. Some of us figured it out though! Use premix!
If you ever have any other Renesis questions, just ask.
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