When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
That chart is a bit confusing! IMO
No port has a bell curve in relation to port area . Once a port is open ...area is static till it starts closing again. And all ports are fully open for a large % of the cycle.
I believe it's just that the one intake curve on the bottom RH side is mislabeled as peripheral exhaust. But what you're saying is shown on the upper LH peripheral exhaust curve.
However, you're incorrect wrt to the Renesis exhaust port. You have to understand how the side port opens/closes is substantially different than the those events on peripheral port as I had explained back in my Hybrid theory posts with the diagrams. On the intake side port it begins opening on the side edge closest to the rotor housing surface and then closes off on the rounded top side of the port. For the Renesis side exhaust port it's more or less the opposite; begins to open on rounded bottom side and then closes on the side edge closest to the rotor housing. They might not be 100% true curves, but they generally approximate what actually is taking place.
The main point being that a side port is not just wide open then closes. There is an area transition through the opening and closing phase due to how the triangular rotor edge orbits over their opening. As I stated on the forum before; rotors don't spin, they orbit.
edit: need to add some clarification; where the side port is placed on the side housing and the shape of it is important to how the phasing plays out. You may be thinking more of the factory pre-Renesis primary intake port that doesn't open until 40 - 45 deg ABDC, as opposed the Renesis primary intake opening positioned at 3 deg ABDC. The Renesis side port is also in a similar position just on the other side of BDC. The secondary and APV ports are positioned and shaped differently and due to this the opening to closing phase relative to the side of the rotor edge position is different. This is largely what many people are missing imo about what makes the Renesis different than just porting a standard 13B.
.
They might not be 100% true curves, but they generally approximate what actually is taking place.
.
The Renesis exhaust should have a significant flat line at peak area and the intakes should be a flatter curve at the top. Otherwise , yes, it does approximate what is taking place.
This will provide a general idea on the side intake port for those who may struggle to visualize it in their mind's eye. The side exhaust port is more or less the reverse (start at lower RH position and go backwards).
Now consider that the diagram above is based on the earlier engines and that the Renesis primary port is not positioned the same laterally or vertically.
The Renesis exhaust should have a significant flat line at peak area and the intakes should be a flatter curve at the top. Otherwise , yes, it does approximate what is taking place.
Edit: Struck out that part below. While the primary intake does have an extended fully open dwell period, the graph is accounting for the primary, secondary, and auxiliary ports in totality. So the dwell opening of the primary alone is not a true measure against what all three ports are doing in combined total. It would be interesting if someone could take a degree wheel and provide the fully open dwell period, accounting for the rotor flank cut as well. However Mazda has all this digitally and can easily project it. At the same time it's just an SAE paper and perhaps the authors did just sort of mimic it with some type of general illustration software. Back when I was in working in the aerospace industry, which we're talking mid-late 80's, even the illustrators there were so talented they could hand draw something like that out pretty close to accurate.
.
This will provide a general idea on the side intake port for those who may struggle to visualize it in their mind's eye. The side exhaust port is more or less the reverse (start at lower RH position and go backwards).
Now consider that the diagram above is based on the earlier engines and that the Renesis primary port is not positioned the same laterally or vertically.
.
.
And the exhaust port is an unconventional shape compared to any other side port. I thought the graph was a bit "stylized", but helps to see the general idea. That diagram helps also.
Originally when I first took an interest in the hybrid theory due to having an abundance of Rx8 parts (3 cars atm) I threw together a timing spreadsheet of a few things. For the purpose of posting in a single image I had cropped it down so it is no longer to any scale per say, but I did mark the opening and closing for each type of port. Perhaps this will help with visualizing.
After reading through Team's explanation of the excessive overlap issue it can be visualized fairly easy with my chart. Where the ren opens so early that inevitably you will hurt your low end, much like with what you see from bridge porting. Probably why KMR says that the hybrid is fine, because that one only saw higher rpm. Now going through the positives and negatives of the hybrid the only reason I could see to stick with the ren would be for the variable intakes which would allow you to have a stock like primary port, but then open up the ren secondary and aux ports to extremes.
My concept from back when:
Spoiler
For NA purposes I see no reason to go hybrid with how well the stock ren works. For turbo purposes there are a whole slew of issues. Mainly the 4 exhaust ports+1shared port complicating your manifold and exhaust pulses. Hurting your twin scroll viability. Adding lots of weight with top mount turbo setup. My idea was that there was an earlier NA FC center plate that looks really close to the fitment of the REN plate. It would require considerable machining to work, port matching and coolant seals. This would negate some of the primary port low end overlap, effectively making your low end similar to an FC. This also eliminates the shared exhaust port issues altogether and would simplify the exhaust manifold to work with a twin scroll. Then for the REN side plates there's not much you can do with the secondary ports. For the Aux ports you can open them up and put in a variable bridge port through the sliders.
In the end it would probably be a gimped low end FC with potentially a decent top end. However the gimped low end and the large volume REN intake manifold would hurt spool.
For me, considering how relatively cheap it is for a new rew block with proven results, why bother with the machining/fabrication hassle on a potentially lazy feeling engine.
it’s a well considered question; with driver it’d have been 2950 - 3000 lbs
.
Wow that is heavier than I would have guessed. That's meant as a compliment on the performance of your engine. I am unfamiliar with how much lightening can be done to the car, so I have no real reference.
I was 200 (and still am ) and eventually I had the car down to 2700 on a low fuel tank. It was slightly heavier at that time though and then it just depends how much fuel was in it, but for what I do it’s rarely more than 5 gallons. So it may have been 2925 or so. That was 10 years ago so hard to be any more specific off my head.
the only spoiler-spoiler is when they build it imo. Again, it still has to be built like a pro engine; which is why most are total junk, and then many people don’t fully grasp the subject as well as they perceive.
Even a lot of earlier 13B PP builds by general enthusiasts pretty much fall flat and won’t even make peak Renesis power. There’s a lot to it and it all has to be thoroughly considered with more than rainbow charts and whimsical thoughts of fancy.
.
I was 200 (and still am ) and eventually I had the car down to 2700 on a low fuel tank. It was slightly heavier at that time though and then it just depends how much fuel was in it, but for what I do it’s rarely more than 5 gallons. So it may have been 2925 or so. That was 10 years ago so hard to be any more specific off my head.
the only spoiler-spoiler is when they build it imo. Again, it still has to be built like a pro engine; which is why most are total junk, and then many people don’t fully grasp the subject as well as they perceive. Even a lot of earlier 13B PP builds by general enthusiasts pretty much fall flat and won’t even make peak Renesis power. There’s a lot to it and it all has to be thoroughly considered with more than rainbow charts and whimsical thoughts of fancy.
.
Hey, if you're 200 and 6'3" no problem, right? Wink,wink.
Ah, I see why you have spent time on the fuel pump. At 5 gallons, I don't think I could get out of an angled driveway with mine. Racing brings all kinds of new concerns I would not have thought of.
Last edited by kevink0000; 07-13-2022 at 08:42 PM.
Anyhoo , I mentioned some time ago that I might get to tune one of these hybrids and it's looking like this might actually happen soon! No date yet but ...soon.
It's 6 port with a semi PP and a custom intake, no valves and 5 exhaust ports, so I'm not expecting it to do very well ...but hey ...will be interesting. I've tuned rx8 race cars with built stock engines on the same dyno so I might be able to get an overlay ....fingers xd.
I rarely had any problem on a S1 module as long as it’s working fine. Typically that’s a weak fuel pump or clogged internal filter imo, but possibly there could be other issues like the siphon system. I never had many miles on mine though, maybe 25k on the original factory one and then swapping in another just for better safe than sorry purposes (still under 40k miles not typically being a street car). The pump/tank mods came later and was done for switching to another higher prep class with full E85 fuel use.
The exception to it is likely sustained high G road racing turns though, but for autox I’d run it down well below the yellow low fuel warning light coming on without issue.
.
Anyhoo , I mentioned some time ago that I might get to tune one of these hybrids and it's looking like this might actually happen soon! No date yet but ...soon.
It's 6 port with a semi PP and a custom intake, no valves and 5 exhaust ports, so I'm not expecting it to do very well ...but hey ...will be interesting. I've tuned rx8 race cars with built stock engines on the same dyno so I might be able to get an overlay ....fingers xd.
With no valves and semi pp it definitely won’t do much below 7000. Whether it proves me to be wrong/untruthful in the end remains to be seen. If anything I’ll just straight up tell you this; if I’m proven wrong/untruthful some of the credit should come to me.
Because let’s be honest, a number of people would be beyond joy for no other reason than to prove someone like me wrong and it’s even a highly motivating factor. I’m fully onboard with that and always said “show me”. If that day comes you can believe that I’ll repent from such a belief with a sincere and humble heart without any issue at all and make straight my ways.
Because I know there are people out there who do have a full grasp of the subject and if anyone is capable of proving it; they are. I may not live in Missouri, but show me just the same.
.
I rarely had any problem on a S1 module as long as it’s working fine. Typically that’s a weak fuel pump or clogged internal filter imo, but possibly there could be other issues like the siphon system. I never had many miles on mine though, maybe 25k on the original factory one and then swapping in another just for better safe than sorry purposes (still under 40k miles not typically being a street car). The pump/tank mods came later and was done for switching to another higher prep class with full E85 fuel use.
The exception to it is likely sustained high G road racing turns though, but for autox I’d run it down well below the yellow low fuel warning light coming on without issue.
.
Well, that's helpful. I am sure its still original and almost 200k miles.
With no valves and semi pp it definitely won’t do much below 7000. Whether it proves me to be wrong/untruthful in the end remains to be seen. If anything I’ll just straight up tell you this; if I’m proven wrong/untruthful some of the credit should come to me.
Because let’s be honest, a number of people would be beyond joy for no other reason than to prove someone like me wrong and it’s even a highly motivating factor. I’m fully onboard with that and always said “show me”. If that day comes you can believe that I’ll repent from such a belief with a sincere and humble heart without any issue at all and make straight my ways.
Because I know there are people out there who do have a full grasp of the subject and if anyone is capable of proving it; they are. I may not live in Missouri, but show me just the same.
.
Nothing wrong with wanting that. Your constructive criticism and observations has furthered the discussion over the years, and that is appreciated.
Anyhoo , I mentioned some time ago that I might get to tune one of these hybrids and it's looking like this might actually happen soon! No date yet but ...soon.
It's 6 port with a semi PP and a custom intake, no valves and 5 exhaust ports, so I'm not expecting it to do very well ...but hey ...will be interesting. I've tuned rx8 race cars with built stock engines on the same dyno so I might be able to get an overlay ....fingers xd.
That will be interesting for sure. There's a lot going on there. I am sure there will be some useful info that will come of it. Please keep us updated.
If I can get my hands on an eshaft and stationary gear cheap, I will do the port profiling. I have the rest. Will need advice on best way to measure port area, however.
adding the peripheral exhaust port housing is pretty much like wiring the SSV and APV to be continuously open on a standard Renesis. Then when they do open you have the same thing with more poop shoveled on top.
Except it’s all going up the primary ports until they open on the hybrid and then you get the extra topping. Which if I understood KM, he had all of them open all the time plus porting it to oblivion. Who says you can’t have your poop and eat it too?
people don’t see, hear, or understand what they think they do …
.
adding the peripheral exhaust port housing is pretty much like wiring the SSV and APV to be continuously open on a standard Renesis. Then when they do open you have the same thing with more poop shoveled on top.
Except it’s all going up the primary ports until they open on the hybrid and then you get the extra topping. Which if I understood KM, he had all of them open all the time plus porting it to oblivion. Who says you can’t have your poop and eat it too?
people don’t see, hear, or understand what they think they do …
.
We agree, and we differ. Timing is everything in my opinion.
Last edited by kevink0000; 07-20-2022 at 09:25 PM.
07-12-2022, 03:27 PM
) and eventually I had the car down to 2700 on a low fuel tank. It was slightly heavier at that time though and then it just depends how much fuel was in it, but for what I do it’s rarely more than 5 gallons. So it may have been 2925 or so. That was 10 years ago so hard to be any more specific off my head.
Goodluck