DonG35Miata

If the power is down 20%, all they need to do is drop the price 20% and the performance/value equation would be fine. IE, a six-speed stripper for around $21,000, and a loaded model around $26,000. Pretty much RSX territory. That's about what I would think it is worth with those horsepower numbers, based on the current market. Hey, for $21,000 I might put up with what I perceive as shortcomings in order to experience that delicious engine, even if it is down on power after all is said and done.

You can't compete in the $30,000 market with around 210 crank horsepower in a 3,000 lb. car, and it sounds like a 6.5/6.7 0-60 is going to be reality. Maybe Motor Trend actually got the 0-60 number right this time!

That said, I loved the drivetrain. Of course, on my demo drive I did not take it into high revs, especially once I realized that I was not going to be taking the car home and it would end up in someone else's garage. I was tempted to bounce it off the rev limiter a few times so I could report to you guys what it was like, but my better side prevailed...

As for the ECU mapping changing at 20,000 miles, if that is true, it is a rip-off. Assuming someone keeps a car for 100,000 miles, you will be missing all that power for 20% of the life of the car.

tripwire

So can I get a refund of some sort? :D

compaddict

This may shed some light:

http://www.rx8forum.com/showthread.php?s=&threadid=7976

Vince

RomanoM

OK, I'm cleaning the BB-Q for tonight, having a Corona w/lime (a Corona w/o lime is a crime) and thinking about this.

Yes I am a dork! Can't help it, makes me a good engineer though.


Anyhow, the RX-8 has an electronic throttle. Did anyone that ran the car on a dyno check the throttle position?

With E-throttles it's somewhat difficult to calibrate the pedal to ensure WOT (wide open throttle) at full pedal travel.


I know more speculation. Oh well!

DocHolliday

Man I want to get involved in these conversations but I don't understand a damn thing you guys are saying.

How about you start using computer analogies so guys like me can understand this crap.

So are you saying that the ATA133 spec doesn't actually transfer data at ATA133? Shocking!

compaddict

DocH,

This is easy. When you tell a RX-8 to go full throttle what you are really doing is telling the computer to open the throttle butterfly to its full position. The RX-8 does not have a throttle cable linking the pedal to the butterfly anymore.
Does that help?

Vince

RX-8 Zoomster

LOL! :D

I think what they're trying to say is that the master drive is not utilizing the full bandwidth as advertised at 8500 RPM's thus creating a low transfer rate to the rear wheel output. :D

..Mark
Systems Engineer

P00Man

blaahAhAhAhaHAhAHaHaHahahahahAhAahahahahaha

i dont know if im the only one thats noticed this but...
it seems that just about everyone on this forum is an engineer, programming, lawyer, stock broker...


you know, everyone seems to be well educated and way more mature than on other boards, and the level of discussion tends to be much deeper and more cerebral

i hope someone in japan on the forum dynos their car thatd be a big help to see whats going on.
i for one am positive that its nothing, agreeing with Mr. Paul Yaw's points of view....but thats another thread....lol
________
Vermont Marijuana Dispensary

Skyline Maniac

So are we ruling out the:

1) Poor dyno machine
2) Poor dyno technicians
3) Port opening issue
4) Isolated pre-production issue
5) Poor driver technique (inability to plant the foot)

We havn't ruled out the:

1) Isolated 1st batch bug
2) Break in period computer limiter
3) Inflated power rating by Mazda
4) Requirement for a rotary specific dyno technique

If the dyno number keep showing up around 175-180, that means the engine is getting around 215hp at the crank with a conservative 17% power loss calculation. If this is really true regarding the engine, then a class action law suit might not be too far in the near future. Some magazines are yanking in 0-60 time under 6 seconds for the RX-8, which seems to indicate more than 175-180whp..... Sheesh, and people were getting mad at Nissan & Infiniti when the G35 dynoed around 225-235. (sedan/coupe)

DonG35Miata

Yes, but is this with a production machine? In another thread, according to a magazine apparently the RX-8 lagged behind some machines like the Crossfire, when it should have been faster.

The cynical part of me says that something was done at the port (hence the delays) that reduced the power output. Some kind of last-minute change, for reasons of emissions, etc. Do they do emissions testing at the port before the cars are allowed in?

Given the power, the fuel economy is kind of disturbing. Has anyone gotten over 24mpg in any circumstances? Even my G35 auto sedan gets 26.5 consistently on interstate trips. Maybe the rotary has a ceiling of around 24mpg in terms of what kind of fuel economy is achievable.

All things considered, even if the Renesis is only 220 hp@18mpg, it is quite a step up in rotary terms. My first generation RX-7 was only 100hp and it got around 16mpg- maybe even less around town. Imagine of the Renesis was made 20 years ago and was in that car- a worldbeater!

If it turns out that the motor only makes 220 hp, I think a package like the S2000, or a latter-day first gen RX-7 would have made a lot more sense.

BillK

I've rarely if ever seen a car that will exceed the EPA highway estimate, so I suspect 24 is tops for what we'll see from the Renesis.

As far as Mazda making an S2000-type car, the point is that Mazda needs the RX-8 to break beyond the sports car field into the driving enthusiast area, thus the rear seats. I don't think the RX-8 will be successful for Mazda if it only generates S2000-type sales numbers...

Shamus

Ok, I've been lurking around here for a couple of months because I'm interested in the new RX from Mazda. You can read my review over at miataforum where I post all the time since I have a Miata R.

It seems to me that most of this angst centers on an assumption of a drivetrain loss of 18%, but is this figure the gospel or myth?

I know from my experience and from several others over at Miataforum, that a 99-00 Miata loses 23% in the drivetrain. These cars are rated at 142hp, and deliver 110 at the wheels. When using this calculation, isn't the RX8 close to the proper figure for a green engine?

Also, the only person I've seen mention it ( maybe I missed it ) was Lock and Load, and he said his resident rotory guru stated 30% is the normal loss on a green engine... what figure is correct?

neit_jnf

In a recent Interview (Rotary News?) Mazda engineers stated that the RX-8 should be putting 204 - 207 hp at the wheels... That's around 16~17% drivetrain loss.

Lock & Load

Shamus you seem to read the threads correctly i believe that the loss in the drivetrain should bearound 30% and not 17% , hey but who wants to listen to an aussie .

loco4rx8

You may be right about the Renesis, but every car I've ever owned has exceeded the EPA highway estimate. 1992 Miata and 2000 Accord V6 Coupe, most recently. They don't exceed it by much, but almost always by 2-3 mpg.

Lock & Load

Maybe %%%%% percentages have a different standard in the US

T-von

I agree, but do you accually think the butterflys are accually wide open when the gas pedal is floored? I was going to bring this point up sooner but the forums have been down. I personaly think the computer is manipulating the electronic throttles operation during wide open throttle. The computer could have been programed this way as a safety measure during break-in until a specified mileage. Look at the dyno charts. All the ports were opening at the correct rpms but, the power was down. For all we know, the electronic throttle may accually have the butterflys only open (for example) at 78%. This could also explain why these engines are running a little rich. This is just my opinion.

compaddict

Are the other engines really running rich or are you not taking into account the cat and how it affects O2 readings?

Vince

TybeeRX-8

And my wife's G500, a real gas hog (which I hate to drive), is getting a little over 15mpg on the highway after 25k miles...cruising at speeds between 75-85mph! It is rated at 14 on the hwy!

rx7 rage

damn.......tony from www.rxecret7.com also dynoed his rx8 and got 185 rwhp.

Gyro

The one thing we do know is that Mazda wouldnt knowingly cause negative "buzz" regarding their new Flagship.

This is the type of vehicle that will end up on Dyno's all over the world. This vehicle is being Marketed based on its "great performance". All of this put emphasis on the numbers that it creates. Mazda IMO would never "overlook" something so high profile like horsepower values. Especially after the mess awhile back with the Miata.

Even IF there was a ECU changeover at a specified Mileage, one that would create HUGE power discrepensies like what has been rerported............Mazda would make it known. They would not benefit in keeping that a secret. At the very least it would have been mentioned in the Tech CD. Which it wasnt. It could have been sent to the dealers to make them aware, It wasn't.

The only thing that I will even consider as a cause is the throttle position value. "Drive by Wire" throttle is relatively rare in passenger cars....I know we can think of a few that have it....but in general. If the system works from a simple potentiometer......then measuring the butterfly apeture wont be as difficult as a digital setup.

With that said I still believe the tests that were done need to be questioned. Three is only enough to raise an eyebrow. The environment the cars were tested in, the Machines tested on etc. One thing is for certain, IF the tests were accurate;

A mechanical or software problem excists with the vehicles.

OR the vehicle is not Dyno friendly and needs special considerations for accurate testing.

and no...I dont think 25 horsepower will "magically appear" once a preset mileage is overcome. Wouldnt that be nice. An answer will be found soon with all the inquirering minds asking the right questions.....thats for sure

Shamus

I saw that number quoted by Mazda's Robert Davis who became Mazda's Sr. VP of Marketing and Product Development in June ( he was product development and strategy vice president ). It was at a question/answer shin-dig w/ Rotary News. ( here's the link http://rotarynews.com/view.php?id=193 )

Not exactly a press release and that's hardly an engineer at the microphone.

Won't we all feel stupid if it was just marketing guy's spicy lunch and bad memory that's created all this 'er, heartburn? (...ok, pun intended)

I'll say it again, the Miata loses 23% in the drivetrain and if the RX8 is similiar, the dyno should show 190hp. 5hp could easily be 'green-ness' could it not?

akrx8

i will agree with that,17% loss does seem low.from my experince 20 to 22% seems more realistic.

P00Man

hmmmm the plot thickens...

if only we new exact details of the pre-prod test cars and of our own, then we could find a more accurate solution
________
ZX14 VS HAYABUSA

Elak

I note from reading other posters that the loss in a drive train is not linearly proportional to engine power. Thus 23% for the Miata (much less powerful) shouldn't be applicable to the 250hp of RX8. More accurate is to cross-compare with similarly powered and built cars. S2000 seems a good comparison in the case of RX8.

/Elak