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Again, I don’t fault you for breathing after and walking in the foot steps of your pal. That’s from your heart though and not your brain.
Apparently you can’t see where he went wrong because you blindly follow him at every opportunity when it’s in response to me. There’s some of the same misapplied theory in there as was made over and over again in the NA header arguments.
There’s no magic well of exhaust gas flow springing forth from inside each rotor housing. As one rotor is ending it’s exhaust release, the other rotor is beginning it’s exhaust release. If it’s siphoning as being proposed, where is it siphoning from?
No, a theory is being partially misapplied rather than correctly modeling how it would have to exist in the proposed system.
So getting back to the original premise of this thread, it perhaps is best to understand what the actual limitations are. Even if we discard water jacket positioning, there are still limitations on the port opening position boundary. Additionally, the port being on the side plate, then the opening and closing points are defined by how the side of the rotor transitions across it. Which as was mentioned in another thread, the rotor doesn’t truly spin about a center point, but rather rotationally orbits about a center point, the radius of that orbit being defined by the stroke of the eccentric shaft throw.
I’ve attempted to show where these boundaries are on the exhaust port of the 13B-MSP in this diagram mark-up
So you can see the inner and outer limitations being the cut off seal path on the inside and the side/corner seal to the outside. The port opening occurs at the bottom and the closing occurs at the side. This is further demonstrated visually in these two diagrams
At this position the Renesis side port is about 5 deg open. Note that the unmodified REW peripheral exhaust port as indicated is already fully open! However the gasses are still expanding and the rotor will advance further before max flow rate is achieved.
. TDC; exhaust port has been effectively closed for 3 deg and primary port will open in 3 deg. At this point the rotor must transition another 48 deg of rotation before the REW peripheral exhaust port closes.
Which you can see in the final diagram how the side and cut-off seals define the tapered end of the exhaust port, which I intentionally didn’t mimic in detail in the first picture to more clearly indicate the boundaries without the colors running all over each other, plus my iPhwn finger drawing skills are not so great.
So in summary, what this shows is that given the the current engine dimension parameters there isn’t much left of significance that’s possible for increasing the port area except to open it sooner by extending the bottom RH corner out to match the cut-off seal travel position and then extend the entire bottom position to match where the rotor side seal would be at an earlier opening position. We can’t get much there though because the water jacket cavities will be penetrated if ground too far.
I suspect that might be an emissions and fuel economy issue for Mazda. The issue for any seeking performance above anything else is;
1. The water jacket limits what can be accomplished there.
2. Creating any overlap is going to have a negative performance impact on how the entire port phase timing is configured on the Renesis.
Just something to chew on until I get around to addressing the subject more in another post.
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Great visual on that Team. I guess I never really put much thought into the leading and trailing edges of the side ports being perpendicular to each other like that and why that affects the port limit restrictions of the Renesis. That really hammers home just how much longer the REW P-port exhaust stays open for; essentially the entire face of the rotor (and of course the overlap into the intake stroke) where the Renesis ports are closed before the entire rotor face has passed by.
Last edited by RotaryMachineRx; 09-30-2020 at 11:01 AM.
I’m taking a lot of time reading your comments about porting. As you put it here the Drummonds numbers (amazing!) you point that any porting will not be a great increase in a Renesis.
these is Eightlien’s race renesis Rx8 with a monster Re amemiya porting. The is a second part of these program showing the tune and dyno with the same 260hp more or less.
As you are saying, your are right that is not a noticeable improvement.
there is another video were Eightlien runs at 280km/h with these engine.
I will try to find the second part for the dyno pic.
That's interesting. The RE Video shows 261 hp at the wheels. Team's builds are dynoed out of the chassis, so it's flywheel HP.
In the video the car looks like it has an exhaust and intake as well. I have no Japanese skills, and the subtitles do not show them talking about correcting the wheel HP to flywheel HP on the dyno.
Unless I missed something, that appears to be a significant increase in the known RWHP increase achievable NA around here. But I could be wrong, as I only had time to watch the 2nd video, and only did so once.
Was it just me, or did the car sound a bit sick after the dyno run?
The numbers on that dyno are surreal. 260PS = 256hp, 38.6kgm = 279 lbft. That doesn't even make sense, this isn't a diesel. I love RE-A as much as the next guy, but something doesn't add up here.
The numbers on that dyno are surreal. 260PS = 256hp, 38.6kgm = 279 lbft. That doesn't even make sense, this isn't a diesel. I love RE-A as much as the next guy, but something doesn't add up here.
Maybe the dyno is showing true torque at the rollers, which might make sense given the reduction of the trans and diff. Can you tell what gear they used?
Look how far towards the e shaft the intake porting goes. Way past where the cutoff seal is and all the way over to the oil control ring. Looks like engine longevity is being sacrificed for power here ?
The question I'm stuggling with is : why has he picked those lines as a limit to how far in to go (it's a different line for exhaust and intake) and what affect will that have on seal life etc?
Hi, just saw the videos, the power is 261ps at the flywheel, 220.9 at the wheels. I think from what I can understand (my japanese isn't great) they are doing a bit of overlap on the center plates with the siamese exhaust but not sure.
Anyways, my car on the same dyno did 270ps at the wheels, 315ps at the crank with about 0.8bar of boost.
There's a guy running the same engine and port mods on time attack here in Japan and he has similar HP, he got close to 270 actually.
Cool video, i've been to their shop, really nice guys.
as Brettus pointed out, I had it all screwed up and deleted my inaccurate comments. My final analysis though is that it really wasn’t performing that great imo.
compare that to this PFM stock port Renesis, near the end of the run when the pedal is finally stabbed to full WOT at around 0:18 sec from near that same point to revving out in a higher final gearing even
you could actually see that on the dyno dial-readout, there was no way it went from 180-190 PS at the wheels to to 260 in another 1000-1200 rpm. the sound of that reality alone; as they turned away from the readout and it revved out that final amount, was apparent for anyone who knows and understands it
Sceenshot of the dial-readout from video :
Maybe you didn't notice .........................the RH dial was in km/hr NOT hp!
well I had that screwed up then and thought it was closer to 7500 too viewing from a 3” screen. Thank you for pointing out my mistake.
Honestly though, *on that dyno run in the video* I’d question it actually making 220 whp. It sounded too bogged down on the top end imo. The port shapes seem more like an exercise in graphic arts than well thought out port timing too.
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after reviewing it again, I agree that they’re claiming 260.1 ps, which on a Japanese roller dyno is supposedly translated into the PS equivalent of BHP/flywheel despite being on the rollers. I’m not sure where the 220.9 PS comparison comes from, because that would be a fairly mediocre output at the rear wheels. Which such a poor baseline brings the whole thing into question for me. It still doesn’t sound like a well singing Renesis on the top end either.
Well ...it's either that or RE Amemia actually found some power. I tend to think it's the latter, but I've only got experience on 5-6 dynos with 40-50 rx8s to go by .
yet people on here want to discount the guy with a stellar 40 year rotary engine motorsport background who was hired by and built special projects for Mazda including use of the Renesis engine, and easily can bury anyone else’s claim to Renesis engine/dyno experience.
Those videos are hilarious. Especially the first one. I needed popcorn.
Admittedly, their gains weren't solely d/t porting. But IMV it's a good effort at adding power and torque via a "systemic approach" on a NA platform, i.e. strengthening multiple weak points.
For those not interested in FI..., if I'm understanding the vids correctly... ~ 30 rwHP, AND ~90 rwTrq NA is respectable...admirable. As Brett said...the impact of that aggressive porting on the life of the engine is tbd.
09-24-2020, 08:24 PM
