just some more diagrams that go along with the subject, it seems that some don’t readily recognize how long the RX7 13B peripheral exhaust port remains open during the intake cycle, coupled with how much further over the Renesis intake ports are positioned toward opening earlier in that cycle.


https://cimg1.ibsrv.net/gimg/www.rx8...0644a4062.jpeg
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https://cimg0.ibsrv.net/gimg/www.rx8...617226b05.jpeg
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another episode of blah-blah-blah, eventually this hybrid cow is going to run dry, gotta admit that I never envisioned him being able to milk it out for over a year now.

Wonder how much longer it will be before we get to see how high the stacked up pile of cow patties is … 🤔


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Its going to be awesome. Look at the Hylomar. 'Nuff said.

keep playing silly games, that goes for the NA porting thread too:

https://cimg4.ibsrv.net/gimg/www.rx8...0d688711ca.png
AWD Dynojet
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he said results were coming the next week, but 5 weeks later ….

anyone taking bets that we won’t ever see any results? :suspect:

but I’m just a negative nancy car forum guy, what do I know …
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This is from an aviation group, which I found interesting.

It backs up what Team has said. Almost word for word in fact.

However, (but no regardless) I believe there is more power available, and I will build one (this decade), hopefully...

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So tis comes up quite a bit, and I and others have to throw reality back into the mix.
The "5-port" motor is a dud. It always has been a dud and it will always be a dud because of basic airflow principles that you just cannot ignore. Kyle has repeatedly tried this approach- first when he was with Tri-point and Mazdatrix and now again while he is out on his won. Yes, you can, with enough money spent, get the motor to run and with enough boost he has gotten OK power out of it. HOWEVER, when you compare that motor next to a similar 13B-REW or 13B-RE the power output is disappointing. My working theory is Kyle needs to market and sell some products and people will buy into this..

Now for some history. Back in 2012 at PRI the Competition Director for the Pirelli World Challenge at the time TC Kline asked what the rotary needed to make 250whp, which was to be the new target HP for Touring Car. I told him a low-boost turbo system is what we needed. Mazda quietly stabbed me in the back because they were phasing the cars out and had no interest in a turbocharged RX8 racing in a Pro series. I then suggested a lower base weight because we sure as hell were not getting more than 230whp out of a Renesis and have it live. Still we tested several configuration, including a hybrid Renesis intake ports/peripheral exhaust ports using a variety of methods to block off the Renesis side exhaust ports. These engines made decent power but were short lived, and effectively blocking the exhuast ports was very difficult. Then suggested the 5-port motor was suggested. We tried the Mohan method, and it sucked NA, very disappointing and very unreliable.The simple fact was the stock side ports worked great up until about 225whp, then... they fell off. The intakes however are HUGE and can flow way more air than the engine could use. The peripheral port exhaust was simply too big and there was a lot of exhaust velocity and other issues like massive reversion. We tried- and several others tried- a sort of "Mail slot" exhaust port but this was far less reliable.

Please note that when I say reliable I mean that the engines would not last a race weekend consisting of 3-4 20minute practice sessions, a 20 minute qualifier, and two 50 minute races without failure.

I could go into all the port configurations we tried and how many hours were spent chasing horsepower with all sorts of exhaust and intake refinements. Lets just say I spent hours and hours on an eddy current dyno running engines in steady state, accel, and decel and in the end it was all time well spent to convince me that there is no snake oil porting etc. to make more power out of the renesis. All the over the counter parts shops can make on a stock engine, if you actually dyno the car, is about 200whp, most will barely crack 190whp with intake/header/exhuast/tuning. Even ported 200 is hard and more than likely the engine will not have a long life. Clean up the exhaust ports- yes for sure, but be careful because the water jacket wall is right there and it WILL CRACK if too much metal is removed, or you create a place where carbon will collect and develop a hot spot. Smooth up the intake ports and port match/clean up the manifold bits- for sure. But forget magic porting templates and BS claims of 240whp.

If you want power out of a Renesis for an airplane, a low-boost turbo is your option.

If you want power for your airplane out of a rotary, the best option is a turbo 13B-REW or 13b-RE.Fear is the spare change that will keep you broke


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ShindenKai

Well-Known Membe

ShindenKai said:
I don't recall Kyle saying the 5 ports gave the Renesis any noticable amount of extra power, just longer engine life/reliability. Side-only exhaust ports for the rotary are terrible.

I never found the 5-port motor to be particularly longer lived than the standard Renesis. It is hard, because we expected so much out of it, but try and wrap your head around the fact that the Renesis is an incredible piece of engineering. It makes almost the same power as the 13B-T turbocharged engine in the FC RX7, almost double the power of the 13B 6-port NA motor in the USDM FC RX7, NA while meeting emissions and it will easily live over 100K miles. To put this in perspective a13B S4/S5 motor modified to make 190+ horsepower would NOT last 100K miles and likely not pass emissions. The 13B-REW that makes 220hp stock in general failed in the 60K mile range, mostly because it had to meet emissions and the twin-turbo manifold castings acted like giant heat sinks that cooked the engine every time it hit operating temperature. It is a simple truth that a single turbo conversion is a reliability upgrade for the 13B-REW.Fear is the spare change that will keep you broke

Great find Kevin! It does indeed back up much of what Team has been saying.
This little snippet kinda backs up what I've been saying as well :p:

I wasn’t aware of that, or where it came from, and don’t know who it is stating it. Strikingly identical conclusions, though maybe not for the exact same reasons.

It’s just like I said in another reply using an example where people might think mounting radiator fans on an intercooler is going to be a positive addition, not realizing that the very best fans money can buy only equate to the amount of air passing through it without fans with the car at 10 - 15 mph. Then the fans also end up blocking flow above 25 mph or so. It results from believing the vision in your mind is correct, when it isn’t. So again, back in the day I thought the hybrid was going to be something special too, for the same lack of understanding that other people still have about it today. So I’m not special or wiser than anyone else.

I just managed to reach that technical understanding. No different than my coming to the understanding about why a length-tuned header has no value on a Renesis back in 2006. Which no different than with it, I’ve laid it all out on this hybrid deal in numerous text explanations as best I could, but if you don’t understand then you don’t understand. Contrary to the people on here who want to curse me in the name of God; who they don’t believe in :scratchhe claiming I never explain anything, but just act high and mighty. Yet I’m still talking to both the wall and the hand again here as elsewhere. So the reason for that is; why bother wasting my time?

The thing is, it was just in front of your face the same as it was mine. Why can I see it and you can’t, or vice versa? So I explained my technical conclusions on why it won’t work with diagrams and details. You have to have something more than a hopey-feely reasoning for still believing it has potential that nobody has found in the last 12+ years yet. So why not spell it all out technically on how you still come to that conclusion, in the same fashion that I did? :dunno:

Let me be honest about why I’m asking though. Because I don’t believe you can. If anything it will only expose your lack of understanding on various technical aspects, the very ones I put forth. If you’re confident though, lay it on me. :)
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Just so I'm 100% sure ....who are you addressing above ?

That's fine, we differ. I don't mind that at all.

I will be posting my ideas, for better or worse, in detail, and have wanted to do it for some time. I am having trouble to find the time, and the parts I need to lay it out. I will put the idea up here first, and then build it. It will probably take forever though.
By that time we will be talking about performance on the 16x, most likely.

It's coming, though. With A re-read of some of what I posted, you might get an idea where I am headed, I thought I was pretty clear here a few months ago. At least enough to get a working knowledge of what I would propose. It's not something I want to tease, I just want to give it a good representation and let the chips fall.

If it works, it works, if not then, like I always say, it's another data point.

Also, you have made basic mistakes in your understanding and perception, fairly often. Both in mechanics and personally. I don't choose to point those out, continually. I would like to advance discussion and not shut it down.

But it seems you would like to:

"If anything it will only expose your lack of understanding on various technical aspects, the very ones I put forth."
That's too bad. It's not just about the topic, it's always about something else in addition.


I have some other controversial topics I want to post about, but I am waiting until I have the info/parts/pictures I want, and more importantly have the time to respond adequately on here.

Even now, I am trying to just get this out quickly, not saying everything I would like to.

lovely, I can’t wait.

just like I’ve said many times and you didn’t mention it; I’d love to be proven wrong, because for me that’s an opportunity to learn something that I apparently am lacking of.

teach me otherwise, please … :)

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Well we will see. I appreciate your response. Like I said it might take a while.

I hope to put up the idea behind it soon, in this thread, since there is so much info here already.

just adding more weight against the fraudulent deception


https://cimg7.ibsrv.net/gimg/www.rx8...d89e19e935.gif



you might want to back up and not stand too close, because it’s just a matter of time before the bow breaks and the cradle falls to crush anything beneath it …
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​​​​​​​

https://cimg1.ibsrv.net/gimg/www.rx8...07780b6a1.jpeg
hey there lil’ guy, aren’t you just soooooo cute ….

https://cimg6.ibsrv.net/gimg/www.rx8...acbb71c97.jpeg
REW primary
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https://cimg8.ibsrv.net/gimg/www.rx8...ca335b5d79.jpg
Renesis; 30% area increase towards the opening side where exhaust overlap will have the greater effect
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and let me clarify that even a full race ported 13B primary port only opens as soon as the stock Renesis factory secondary port. And the factory Renesis primary port opening at 3° ABDC can only be achieved with a Bridgeport on the 13B primary port. There’s just so much the average person, and even so called rotary masters, are not perceiving the full truth on.

And yet, none of them ever will ever understand the design concepts of the Renesis until they so do. Mazda engineers thoroughly understood, but most enthusiasts and so-called rotary experts still do not.
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https://cimg8.ibsrv.net/gimg/www.rx8...ab234e3702.jpg
Finally got my hands on a GSL-SE housing for measuring, etc.

Stock ex port size 42mm (at peak of side ellipses) x 23mm.

the GSL-SE engine only made 135 bhp and 135 lbs-ft from the factory

most people don’t fully comprehend what it takes to get that engine anywhere near the performance level of the Renesis. Which it never actually will in the lower half of the powerband.

here’s another past crash & burn thread on the subject

https://www.rx8club.com/series-i-maj...-ports-256081/

at the very end an engine was built by somebody else later (down in AUS I think), never any dyno proof, a lot of ballyhoo, clearly it never met expectations, and was supposedly sold (was listed in the FS area) to be replaced with an REW instead, and vanished never to be heard or seen from again.
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https://cimg2.ibsrv.net/gimg/www.rx8...59e0ec42a.jpeg
over 9 months later …


https://www.rx8club.com/general-auto...2/#post4985674

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another turbo one, makes no sense for 300-350 whp but no point repeating myself, no excuses or questions on the build quality though




you’ll probably have to follow it further on his own channel

https://www.youtube.com/channel/UCyy...3b7F56tH4MLgpA
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Agreed . Considering the Renesis can make that power with ease on a stock block and be reliable with a few tweaks.
The rx7 apex seals with modified rx8 corners plus dowells/studs and oil pressure mod are worthwhile IMO.
The hybrid idea ..... will kill spoolup and allow for more power , but will it improve reliability? :dunno:

I notice they didn't go for RX7 rotors .... Team, you have mentioned in the past that Pettit says they bypass too much air into the sump even with the cutoff added. Is that the only drawback?

Mazdatrix/KMR use the Renesis rotors and so does every hybrid that I know of. The special Pettit Stage3+(?) Renesis engine isn’t a hybrid configuration. They were taking RX7 rotors with a lower compression ratio and adding a special cutoff seal to make a 9:1 compression ratio Renesis for turbo use. The Pettit rotor setup has limitations because it still lacks various Renesis specific rotor features, but not really wanting to take the discussion there since it’s not applicable. A lower compression ratio is only going to exacerbate the Hybrid issues.
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That ex port is HUGE. Wrong approach, again.

and they did their full CNC port on the Renesis side exhaust ports as well. The intake ports too, but those are never going to flow any where near the exhaust port potential no matter how extreme. All for mid 300 whp no less.


https://cimg4.ibsrv.net/gimg/www.rx8...da8c54734.jpeg
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when it comes to old school 13B guys and the Renesis though, no surprise.
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Amen Brother.

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