Mazmart

iTrader: (12)

The front pulley would tend to wobble since they bend at the front and I would suggest that it may have tried to go in 1st gear momentarily even though you wanted 3rd.

Back to our regular scheduled program though

Paul.

neit_jnf

12A sized all aluminum turbo DI renesis would be nice.... or a 12A based all aluminum 3-rotor!!

RotaryPhil

That IS an original concept! Wonder if Mazda ever thought of it?

longpath

iTrader: (1)

If I had my wish, I'd want the "high end" version of the engine to use 10A rotor width (when I crunched the numbers, it came out to approximately 1.3 Litres) and have an integral Wankel supercharger. It would look like a 3 rotor; but be much less thirsty at idle and yet perform like a much bigger displacement engine.

HiFlite999

iTrader: (2)

wouldn't work, there's no way to gear that 3rd rotor to run at a higher rpm than the motor itself. to run at engine rpm would require the supercharger to have a displacement very much larger than what it's charging.

zoom44

well if you stack the wankel SC on top of the motor....

neit_jnf

you can also have same sized rotors on the same shaft like a 13B. One rotor can charge the other one in a 2:1 ratio if we have ports on both sides of the housing of the air-pumping rotor. But it needs to be in pairs, one to charge, one to be charged or if there are three two would charge the third one.

sorry for the quick and ugly drawing

elysium19

iTrader: (1)

That will certainly make more power but will it be disproportionately less efficient as well?

PhillipM

Too big, too heavy and too hot for the incoming charge - better off just sticking a rotrex next the alternator.

longpath

iTrader: (1)

Purely devil's advocate; but would you have been willing to spend an additional $2K to $4K if it had let Mazda use a catalytic convertor sturdy enough to not have to sacrifice the mixture and engine reliability in order to keep the catalytic convertor?

For instance, if the cat was electrically pre-heated (to get the fast light off time) and set one to two feet further back (to keep the peak temperatures tolerable without ruining the mixture) or the cat was actively cooled (sufficient to keep the peak temperatures within acceptable levels without resorting to poor mixture) but in the current position or even set closer to the engine to maintain or even improve on the light off time, and the cost of that technology raised the price of the car $2K to $4K; but it performed like a properly tuned model with a resonated mid-pipe, would you consider it?

It seems to me that the 16X isn't really the problem. To me, it seems that the inadequacy of the current cat Mazda uses is the source of the overwhelming majority of the shortcomings of the current Renesis and would very likely be the source of problems for the 16X as well.

Spin9k

I think you got something there. The CAT being so close to the manifold is the reason for the rich tune, which keeps the power down, spoils midrange response, and helps ruin the mileage.

Symbioticgenius

Mazda should design something better than a Cat to reduce Emissions. Not to say I know what, but some type of filter, that didn't reduce power.
Not only would it benefit Rotary, but they could sell it to other companies and make money.

I however could care less about emissions.

arghx7

you're all making a big deal about the tune just because of the different reflashes that Mazda has had. there's nothing unusual about the way mazda currently tunes the Renesis. The AFR's are just like a piston engine. Even a frickin Z06 runs richer than 12:1 AFR's. Here is a chart of WOT fuel on a completely stock Rx-8. This was taken from a log that somebody posted for me in the tuning section of this forum:



Ok that's definitely richer than what people tune for in performance applications, but compared to other stock piston engines it's not that different. Here's the target AFR table on a nonturbo Subaru Outback (175hp?), which is of course not really a performance engine.



The Rx-8 may run a bit richer than that in some spots but not that much richer. Now here's the target wide open throttle AFR table on a 500hp 2007 C6 Z06:



So the Corvette Z06 is actually tuned richer. The Renesis WOT tune is pretty close to industry standard.

HiFlite999

iTrader: (2)

Since you posted this in another thread as well, I'll respond the same way: WOT isn't what gets you 22 mpg highway in a small 230 hp car. The mid-range, light throttle mixture is too rich as well. I'm not the expert, but this has been established repeatedly by experts in the forum.

heyarnold69

iTrader: (1)

sorry but my 8 runs rich

Mazmart

iTrader: (12)

Amen! RX8s are rather rich through portions of fuel maps that would not be the case if the cats could handle the heat. Mazda is now becoming quite excellent at catalytic technology so perhaps they can make leaps forward in this regard.

Just imagine; no sooty exhausts, very little carbon build up and world peace

Paul.

rotarygod

It doesn't help mileage from the fact that your engines are spinning a 25K rpm (maybe a slight exagerration!) while highway cruising!

muythaibxr

We need a 7th gear.

pking1122

^ Then kiss your manually operated single clutch goodbye. DSGs are taking over.

longpath

iTrader: (1)

My charcoal black soot deposited OE exhaust says mine does too.

Yes!!!!

I agree with that as well, and have long held the view that the rpm drop I see from 5th to 6th is less than I want. To be frank, I like the gearing for gears 1-5; but I want the 6th gear ratio from the automatic! If I short-shift at 3K RPM in gears 1-5, the RPM drops back down to 2K; but when I shift to 6th, it only drops to 2.5K. This tells me that 6th gear is shorter than I want it to be.

On the bright side, the additional displacement and torque from the 16X should facilitate using a taller 6th gear ratio. On the other hand, if Mazda was releasing even the current engine with a tune similar to what TeamRX8 uses, they could already be using a taller 6th gear with no worries whatsoever.

My suspicion is that the the 6th gear ratio was selected for the EPA test conditions and not what would produce real-world best fuel economy where the simple reality is that that the posted speed limit is slower than the actual speed of traffic more than half the time (at least it is in CT where, at one time, Federal highway funds were in danger of being withheld because CT could not achieve even 50% compliance with the 55 mph speed limit).

SlideWayz

I think the reason why 6th is so short is because the Renesis doesn't make enough torque/power @ 2k rpm to hold speed uphill.

longpath

iTrader: (1)

Then this would seem like an opportunity for the 16X with its larger displacement and torque.

hornbm

iTrader: (1)

Yeah you guys want a taller 6th? Seriously? I floor the car in 6th at 65mph, and I swear I can hear the engine laughing at me.

longpath

iTrader: (1)

Yep, I want a top gear for highway cruise conditions and I want the RPM drop to be consistent for each upshift. I prefer to downshift if I want to dramatically accelerate.

Rote8

I do not seem to have that problem....