WTBRotary!

iTrader: (6)

Stock engine? What does stock mean? If by definition you mean all stock parts then yes, my engine is stock. The only thing it has had done to it was minor port work, basically cleaning it up, nothing aggressive...

If by stock you mean built by Mazda then no, it's not stock.

200whp stock 8 would be impressive, but as I've said in the past, stock 8 with absolutely no mods should put down 180-190whp.

My new engine is built with all stock parts with minor port work. You do realize BHP is Hp at flywheel right?! It would be impossible to put down 210-215BHP if you have 232BHP. I think what you mean is 210-215 Wheel HorsePower, which still wouldn't be possible if you only have 232BHP because of the 15-20% drivetrain loss.

I know the cards I'm holding, I'm not setting myself up for disappointment... I can send you the Dyno sheet if you'd like to see it...

Carbon8

iTrader: (4)

My "stock" 8 managed better than 200

Its out there, just not common.

RIWWP

iTrader: (2)

Power is very sensitive to build quality ambient temps, specific dyno, and dyno calibration.

There was a video posted up a bit back about how someone dyno's a largely stock Neon at anywhere from 130 some whp to over 1,000whp, just by changing the dyno settings.

Quoting a peak number from a single dyno has about the same amount of worth as piston rings are in a rotary.

WTBRotary!

iTrader: (6)

Yeah... Technically it all depends on how the engine is built... There are stock 8's with close to 200whp...

It's also important to remember chassis dyno's are different than engine dyno's but it still holds true about calibration...

Carbon8

iTrader: (4)

Im not saying it was a real representation. It was what the dyno printed out .

Just seems everyone gets so worked up on numbers that are relatively meaningless.

RIWWP

iTrader: (2)

I have a dyno sheet from my 8 that shows 700 wheel torque. Jedi's 1,000whp dyno sheet is another one.

Just make it a habit of not believing any dyno's at all, for any reason.

200.mph

iTrader: (9)

iirc my first pull had me at over 700ft/lbs of tq

Carbon8

iTrader: (4)

IMO, a dyno is their to give representation. Keep the same dyno and settings and see how changes effect your numbers. Then forget those numbers because they hold little merit in a real world applications compared to other cars and their numbers

9krpmrx8

iTrader: (46)

Well WTB's dyno sheet is an engine dyno sheet, not a chassis dyno so it is likely very accurate. Especially considering who built his engine. But yes, comparing chassis dyno numbers is useless.

ecookman

I bought a 04 RX8 2 months ago now that wasn't running, have put almost 5000miles on it, 100K on the ORIGINAL ENGINE, 6 previous owners, couple scratches and dings, really effed rims, car looked very abused and got it along with a greddy turbo kit with tonnes of extras (which i'll probably never use) for 4k.... but minus a transmission that desperately needs a rebuild, and a passenger side airbag fault NOT A THING WRONG WITH THE CAR
and I drive it like a bat outta hell.

Nathan Atkins

Dude did you even read what I wrote? My point was that the "232" claimed by Mazda is optimistic, and that the true horsepower, the crank or brake horsepower as measured at the flywheel is more like 210-215. Pretty much everything else you've replied with in some way is you completely misunderstanding or misinterpreting most of what I've said.

My point all along was that stock for stock the rx8 doesn't make appreciably more power than the frs/brz. At least not enough to point it out as a distinct advantage.

As for your dyno sheet, I'd love to see your engine dyno data if your builder provides one, I'd be stunned if you had a streetable n/a renesis that made a genuine 232 at the fly wheel.

J8635621

iTrader: (10)

Prepare to be stunned then. It made way more than 232

J8635621

iTrader: (10)

https://www.rx8club.com/series-i-major-horsepower-upgrades-93/engine-dyno-testing-renesis-88067/

puppet623

iTrader: (1)

i like that post :P im to new to dig that far back lol

Nathan Atkins

WTBRotary pm'ed me a dyno sheet showing a power peak of 263hp at 8300 and a torque peak of 182#ft at 7100, I'm guessing based on the fact that this is about 10#ft higher than the typical renesis torque peak at 5500 that this engine is supercharged, but he said its NA. It could be an aggressive port job, but I'm more interested in streetable power. It could be what he said it is, but it looks suspiciously like a supercharged dyno chart to me.

The discussion I read in the thread J8... Posted is pretty consistent with what I was saying earlier: that the renesis is optimistically rated, it always felt like 200-220 to me so thanks for pointing out that someone has verified that.

That said, an NA renesis that puts out 260 some odd horsepower at the crank sounds pretty cool and if it was streetable, I'd be interested in having this myself. But really I'm not unhappy with my engines power output, just the fact that the Subaru manages only slightly less power while returning excellent fuel economy.

9krpmrx8

iTrader: (46)

WTB's engine is NA. That dyno sheet is from an engine dyno that his builder (think professional builder $$$$) provided him. And of course it may be a custom tune that was used on the engine dyno and obviously the exhaust setup would not be similar to what it would be on a car, but the results are what they are, an NA engine making serious power.

But it's no where near unimaginable, the race guys have been making 240WHP+ on the Renesis for quite some time now.

RIWWP

iTrader: (2)

That's largely a matter of thermal efficiency. The rotary is mechanically efficient, it's just terrible thermally.

Also contributing to the higher is a higher compression ratio, a torque peak (it's double-humped if you look at a chart) at 60mph in 6th gear which helps inflate the EPA number, it's ~250lbs lighter, and it is equipped with Prius low rolling resistance eco-tires. The prior Subbies aren't much higher than the 8, showing you how much those points make a difference.

So keep those points in mind if you would make changes that would affect it, like tires with something called grip or cruising higher than 60mph.

Nathan Atkins

RIWWP, I took my wife's car out autocrossing and posted a similar time to my RX8, on her prius tires, and my 8 is on star specs. In my buddy Greg's BRZ with Direzza Z2s I was another 1.2 seconds quicker than that (~40sec course)
It galls me to say it because I've loved my car since the day I bought it, but the BRZ is a better car in a lot of quantifiable ways, the only reason one should choose the 8 is just if you really want one. As I did, but now having lived (and competed) with both, I'd find it really difficult to justify choosing an 8 over a BRZ. I will continue to enjoy my 8 until the day comes that I pass it on, but I'm happy knowing a worthy successor is waiting for me.

Nathan Atkins

I'm glad to see it. I know the engine has it in it, I just wish it had come that way.

Mazda's goal when they set about making the Renesis was to produce similar power to the outgoing REW without turbocharging, I just wish they were a little closer to the mark, and subsequently more honest about missing it.

MS2019R3

No question...the rx8

RIWWP

iTrader: (2)

Quite a bit of the gains race teams have come from reducing drivetrain losses.

They also shuffle 100,000 mile reliability off the list of attributes they are going for (the engines don't last all that long on the track, side seal springs can't take the heat)

What do these 2 points that tell you?


It's also largely pointless to continue to be upset about published HP ratings for a car that isn't produced any more and there is a long history proving what the cars make at the wheel and what you can expect.

WTBRotary!

iTrader: (6)

1. Its not an aggressive port job, I told you its had minor work done, clean up mainly. Think more along the lines of, my engine is properly built, by an experienced race engine builder. Your engine is not... Its simple, not sure why you cant imagine a Race Spec Renesis putting down this much power.

2. Do you really think a supercharged Renesis would only put down ~35 ft-lbs more of torque and only ~50hp more hp?

Heres an Idea guys, not sure why its not been obvious to some.

Mazda... The guys who have put in the man hours with the Rotary engine for a few decades, knew the Renesis could produce HP around this range... Take my engine for example. When you factor in drive train loss of 15% that only leaves me with ~220whp. Not too bad, But obviously its about the way the engines were assembled and who they were being built for (i.e. The general public). So Mazda made the seal clearances/tolerances a little less perfect, detuned it, and made it for the public. Its not hard to imagine a stock Mazda built Renesis putting down 40/50hp less than a Race Spec Renesis. Obviously the goal of my engine is completely different than the stock Mazda Renesis, which is required meet emission regulations, and reliability tests (supposed to).

So 250hp becomes 238, 238 becomes 232 etc.

The Rotary engine has never been fuel efficient, so I'm not sure why you're getting upset about MPG now...

Nathan Atkins

Obviously the car is competent, I'm able to beat the likes of the 370Z at autocross with a hundred less horsepower, don't let the fact that I'm satisfied with the performance of the car be lost on you. It just should say something like 220hp on the window sticker since that's about what a stocker puts to the crank.

Either way, my point was that my power isn't significantly higher than the BRZ and that's still true regardless of what people are able to do elsewhere. My unmodified 8 is not significantly more powerful than my wife's unmodified BRZ.

And the only reason why I've chosen now to start whining about the MPG is that before this year there wasn't another similar car that is just as fun, damn near just as practical, and twice as fuel efficient, sitting in the driveway next to mine. It seems a perfectly reasonable view to have.

Nathan Atkins

yes, yes, they kept dropping it lower and lower (no changes to the engine, just what they said) but they still didn't say the 215-225 that it actually is. Weirdly I think it was Jeremy Clarkson's review when he said 228bhp that was the most accurate ive heard, and it was that very review that put an RX8 in my driveway, so clearly the inflated numbers weren't necessary to secure sales, just seeing the car in action was.

RIWWP

iTrader: (2)

Since when does the peak power noted on a window sticker matter?

If you are going to complain about window stickers of a car no longer produced, perhaps you should complain that the number isn't relevant on ANY car out there? Why don't manufacturers use a wheel power number? why do they even care about peak power anyway, if it's really power under the curve? Why don't they list the power to weight ratio, since that makes a big difference? etc...


Are aren't disagreeing with you generally, we just don't see why you are taking exception to insanely old news that never mattered in the first place.