Mazda changed from 2 injectors in the primary port plus 1 in the secondary to 1 (larger) in each port with slightly finer spray patterns. I don't think that changed the power output in any way. Smallish differences in injector size and spray pattern , from what I've seen for myself and observed from others, seem to be relatively inconsequential.
What TB are trying to demonstrate is that having injectors in every port is better for power than leaving any port injector free. Sounds like they are going to do some in depth analysis of this ....I await with interest.

 

I'm also very curious, but coming from scientific side, I hope they do a proper analysis eliminating other variables (or at least accounting for them).
They are showing 5% increase in power across at peak which is HUGE for just changing the fuel injectors, and they show almost 20% increase at 3350rpm and >10% up to higher rpm where it drops off... .... To me that gives a red light that the difference doesn't come from what they state (6 injectors, 6 runners vs 4 injectors for 6 runners)


notice, this image is from the same post.. if this is used for comparison than the discussion is in completely different direction... Having injection on to the PP port having fuel cooling the apex seal will reduce drag and improve sealing ...

 

I was thinking they were showing results from 4 injectors 4 runners vs 2 injectors 4 runners .

 

it really comes down to balancing it put with the proper sized injectors and then the staging balancing as well

pretty much the same when Adaptronic released their Modular RX8 ecu and Andy reworked the balancing on an NA Renesis to find more power

edit: oops, same dyno graph as above, doh!
.

 

This may be more of a question for REW vs REN. On the Rx7 club I see many quoting that people push 500-600hp on pumpWM setups. What differs on the REN where this wouldn't be the case, or where the REN ceiling should be lower?

• Compression?
• Apex seal depth?
• Side Seal durability?
• Intake complexity? (you noted WM collecting in the intake for one point. Then to add with all of the valving compared to a rew)
• Side Exhaust flow, Siamese, collection/split issues?
• Exhaust overlap or lack of?

I guess what are current bottleneck issues holding up the 6port REN? I had thought you were already running WM for mid-high rpm to achieve your previous ~420hp range. E85 does seem to be the simpler solution, but should be unnecessary based on the other rotaries.

Blocking/restricting the APV almost makes me start to think back to the 4port turbo concept. Looking back at mazdas previous designs they favored 4 port turbo engines vs 6 port. Where the Primary was shorter duration than the secondary. With them being relatively close. For NA it seems to be the opposite where the pri is slightly larger than the sec, but the sec is also paired with equal duration aux ports. APV blocking or restriction seems to just mimick something closer to a 4 port except with a convoluted intake. Here's a link to an rx7 thread for port timings and durations of various mazda designs over the years. link
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While I already am building a REW setup, my other poverty stricken Rx8 may just be a REN test monkey in the future considering I have 3x 6 port engines. Thinking into the future, used REN plates will be more available and cheaper than REW plates.....unless billet plates get cheaper. Right now the dynamic still seems to be REN until 350HP and then go to a REW for 350-500hp Pump and then E85 for 500+. If we got that ceiling up for a REN to reliably hit 400-450 for a street car, that would be a great spot to sit before you get out of the drivability range anyways.

 

Depends on who you talk to. I'm of the opinion it's lack of exhaust port timing past TDC that's the issue (https://www.rx8club.com/series-i-maj...theory-268776/). Some say if you fit a big enough turbo, that can be overcome. But then there's ......lag.

 

perhaps an SC with bridge port with overlap BTDC being able to flush at least part of the and ~0 backpressure :D (above atmo that is) + massive port job on the inners of the exhaust port to remove choke points..
that's my hypothesis at least, will see how it pans outs .. .

​​​​​​​its not like 500hp 13b as responsive as your setup at 400...

 

Otherwise in terms of just WM, there is no reason pump gasWM shouldn't get us higher.(perhaps higher comp still would lower the other rotary pumpWM vs E85 threshold) Meaning you still think it is just engine limiting issues. I will continue on that other thread as my next comments are directed towards engine based kaboom theory.

Mainly I went down the REW route was to have the ceiling in the future to ship E85 to me and go above that ~550hp threshold. However if I can get 400hp on a REN pumpWM I'd probably settle for that considering the drastic price difference in engine parts.

 

That does make some sense to me - worth trying! The big issue with SCs and a rotary, IMO, is the extra boost it takes to overcome the power to drive the unit. Add that on top of the additional flow required for a rotary and things go from bad to worse as far as size and weight go.

 

The parasitic power draw is very simmilar between a supercharger and a Compressor needed to power the turbine of a turbocharger.
The work on the turbine is not free. The Emap makes the engine a small compressor . I haven't measured exactly the power draw of a turbine (or loss of power due to emap)

According to Gale Banks, the only true difference is that a turbocharger draws power while exhausting and supercharger while combusting.

​​​(This is only applicable to modern SC's with high efficiency, not old roots that barely scrape 40% efficiency).


The weight penalty is true, especially since its on top of the engine (or in front).
I'm sad i havent PP'd the exhaust like you did on the NA.. plans for upcoming years

 

It might be the same power to drive the actual compressor wheel ........... but the effect on what power is available at the flywheel is DEFINATELY NOT the same!
I think you are forgetting that a turbine is driven by both heat and pressure. A large % (not all) of the energy is in fact 'free'!

 

I am not forgetting that. I will calculate tomorrow how much load is on the engine pushing 2 bar EMAP. (Or more, i dont know what is on your setup).
The driving of the turbine comes from the pressure differential, the drop of temp across the turbine is just conservation of energy, same way that air heats up on the compressor side. Loss of heat energy beyond that is actually loss / inefficiency.

There is no free energy, and many have spread "turbo is on free energy" for decades, it is far from true.. and maybe a very small percentage is "free"..

It was considered as "free" since 30 + year old SC were very inefficient.

If it was mostly free, than 1 bar boost with good intercooler would result in exactly 2x power.

 

You should probably just look at results rather than fancy calculations. There are enough on this forum to see the difference.
And yes, we can make 2x the power at 1bar of boost !! Within a few % points.
And also yes ...there IS some energy available to the turbo that is 'technically free' in the sense that it's available without detrimental loss. Sure there is some power taken out of the engine through backpressure .... less than half as much as a SC drags out of it though!

 

Update:
Slow progress on the 400whp pump gas goal.
First thing was fitting the Haltec PNP ECU which has taken me the best part of 6 months to come to grips with. Seem to have it sorted now so ...onward!
However:
Recently got a txt at 7:30AM from a friend in a nearby town saying "what's Red doing in Cambridge?". Immediately ran down to my carport to see, much to my horror, Red definitely gone!
Raced over there to pick her up and found, much to my relief, minimal damage done. Door dented, ignition lock ripped out and plastic surrounds mangled.
First thing I did when I got home was to check the Haltec logs to see what they had been doing ..... No burnouts .... just a joy ride in which they topped out at 260km/hr!
So engine and drivetrain is all good. Suffice it to say I've upped my security game considerably since then.
Anyway, after spending a few weeks getting the damage/security sorted etc finally went out tonight to do some logs.
This is where I'm at @13psi as far as power on pump gas + w/m goes:



Not impressive considering where it's been at in the past but it still feel very quick at this level.

 

Brettus: yikes man, sorry to hear someone swiped your car but glad to hear you were able to recover it and no major damage.

 

Thanks Jedi, never happened to me before so was a real shock, even though I basically found it before I knew it was gone.

 

I had tried to weld this up myself but it turns out ... I didn't know s**t about welding plastic as it was leaking badly again. So I took it to a pro plastic welder. Hope it hangs together this time. Forgot to get a pic but it looks like it's gunna be ok.
This has to be a problem for others using stock UIM as it's happened to me with three separate UIMs so if you have a turbo with a stock UIM ..... check for leaks on bend closest to firewall!

 

a simple solution for this would be to cut of the "weld flanges" and wrap the UIM in carbon fiber (or alike) to seal it.. 2mm thickness would hold 50 bars on such a small diameter.. ...