Lawsuits? LOL LOL LOL so funny ......

 

Already done in Japan, 4 port "low power" 5MT vs 6 port "high power" 6MT... They got very similar numbers

Anyone knows the thread where they posted this?

 

Well, didn't Mazda have to anne up for the Miata fiasco. It may not have been brought to court, but it was embarassing to them to say the least. It hurts the image of Mazda.

 

Ignition timing is certainly capable of making a difference - far more than mixture does on a normally aspirated engine. Whether it will free up 20 hp or not is another story.

Modern engine control systems play a complex game of balancing ignition timing, knock and normal engine noise. On a rotary, playing this game fast and loose has more severe consequences than on a piston engine. Perhaps Mazda went extra conservative on knock sensitivity? Who knows, its really all speculation at this point - all we know is that something isn't right above 6000 rpm.

But, if its an ECU issue, I think it has something to do with ignition timing. I suppose the intake manifold system switches could be incorrectly hooked up (explaining the big dips when the runners open up), but that would seem to be less likely to me than an ECU reprogramming snafu - especially considering the work that went on in the ports and the OBDII issues.

SC

 

if this car is not running "that" rich im wondring why mine with only 250 miles that the tail pipes are allready very black with soot.im still beleaving its a combo of things,rich a/f,timing, etc.i also have not reved over 6000 and this soot is very,very black and has coated both tips very heavily and at only 250 miles. to qoute paul yaw, this thing is "pig rich".i think we need to call and e-mail mazda endlessly so we can get a ansewer. i will say this,i love this car,for me its the funest,quickest street car i have ever drove and it would be freakin awsome if we can get this 15/20 hp back.

 

Good to see you here UL.

RedS2.

 

From the tailpipe description it looks to be running very rich. For comparison sakes, the Prelude engine is desined to run rich, especially when in VTEC. Many club members reported much less black soot after installing a VAFC and leaning out the mixture on a dyno.

 

Perhaps the below pictures can show the problem a little bit better. I took the Mazda released RX-8 hp and torque curves, subtracted 17% for all values and graphed them. I then pasted the hp and torque curves over the dyno results from SC.

It appears that the dyno hp and torque curves are very close to or a little bit higher than the (claimed - 17%) UNTIL 6250 rpm. Of course we are all aware what happens at 6250 rpms yes? A problem with the auxiliary port or FAD may or may not be part of the problem but that hp curve does look pretty smooth until 6250.

Realize that the missing hp should instead be described as the missing torque at high rpms. It apears that around 11 ft-lbs are missing at 8500 rpms and about 19 ft-lbs are missing at around 8900 rpms.

With patience, the answer will eventually reveal itself.

Brian

 

Buger's graphs are back! Good stuff as always. Thanks - I almost understand what is happening now.

 

Have Mazda optimised the ECU to give Joe Bloggs (and maybe even the press) more torque lower down at the expense of those of us who like to rev the car? Maybe even trying to optimise the 0 to 62 mph?!?!?!

 

First of all, it is a rotary. If you have seen other rotaries you know you will get sooty tailpipes. Also timing retard can result in incomplete combustion causing poor mileage and soot build-up.

 

That latest dynopack runs look a lot like the 89 NA motor I put in my 84 RX-7. The variable dynamic intake(VDI for short) valve was stuck closed. The 89 had a less complex but similar variable length/configuration intake. Right at 6,250rpm my dyno plot and AF's went screwy and it just wouldn't make any more power. No matter how much I fiddled with the timing & fuel- I was running an SDS programable EFI system- we couldn't get any more power over 6,250 rpm. When we discovered the sticking valve power shot up 20+hp. just seems the RX-8 is acting strangely similar to me.

I don't have any plots of this since it was during tuning and not the final "product".

 

For those wondering what kind of times the production cars are turning out, the latest issue of Australia's "Motor" mag turned out the following times:

0-100km/h
* RX-8 6.99
* 350Z 6.45
0-400m (1/4mile)
* rx-8 15.12@151.8km/h
* 350Z 14.49@161.4km/h

 

I thought the Z was 5.4 seconds?

 

No two mags are the same. Australian mags test the cars side-by-side on a race track, with a tank of fuel. Both cars were lined up at Calder park with the 350Z (a touring here) getting the same times as Wheels mag did last month. What important is that Wheels rattled of a 6.4 0-100 and 14.8 1/4mile for the RX-8 from what looked to be a pre-pro car. In other words the Z's consistent times seems to indicate that the rx-8 tested by Motor was noticeably slower than that tested by Motor. Both mags use a Corevvit.

-pete

 

What is the hp rating on that car? 247 hp? If so then there is a problem. There is no way a 3000lb car with 247 hp should be pulling off 15.1 1/4 mile times which is the same "magazine" 1/4 mile time as my 2950lb, 200hp Prelude. Let's hope Mazda can fix this quick.

 

Lets clear this one up:-

1 BHP (SAE) = *1.01387 BHP (PS) = 0.7457 KW

For all practical purposes this is not a concideration... EG, the RX8 is quoted at 247BHP (SAE), or 250PS.

 

im wondring why we havent got any info from mazda yet,i found on the aussie forum lock&load wrote a letter to there guy and received the replie within a few days.looks like only the us cars have the problem and havent seen a post from rotary news in quite a few days. i still love this car and seems fast but i really just want to know, wether its good or bad.just spill the beans mazda.

 

What are the expert opinions about this?

 

Yeah, but that's isn't what's happening here.

That tip refers to what the BMW M3 does for example. It will completely cut fuel at a lower than maximum RPM. So you can't go past a certain RPM at all until the coolant reaches a certain temperature. In essence, your new redline is at 7000RPM until the engine warms up and then it begins to gradually rise until the engine is at optimal operating temperature.

The RX-8 will still go all the way to 9000RPM and even a bit past. It's just not making the expected power.

 

Just a thought...

You're missing, what... 20Bhp?

The European ECU is missing 20Bhp due to the more strict Euro4 emissions regs... perhaps you have been given this ECU by accident... 228Bhp apparently... BUT I hope that isn't the case, because the plot shows somthing wrong, not just lower output.... It'd be really bad if this was the plot from the Euro ECU.. .

 

I very much doubt its the Euro ECU. Running ritch wont help the car pass Euro4 emmisions now will it?

Also our cars have been delayed until november because of the new emisions settings.

 

Just because that's the way the M3 ECU does it, doesn't mean that that's the way the RX8 ECU will do it.

---jps

 

I doubt they'd fit the wrong code by accident. But it could be that they had difficulty meeting the US emissions spec and had to do the same kind of thing that they have done with the Euro ECU so it ends up being very similar. Note that the peak power is now at around 8200 not 8500, same as Euro spec. I'm not sure it looks wrong, it just looks like they have absolutely killed the top end, which I fear is exactly what they have done to the Euro spec cars too.

There has been speculation that they programmed all the ECU's while they were in port. This almost certainly means they were still working on the ECU code right up until the last minute (they finished writing it while the cars were being shipped). They already had working code in the Japanese production cars, so why all the last minute changes? US emissions is the only thing I can think of, they must have had difficulty simultaneously satisfying power and emissions requirements. Maybe they even held back the cars in port for another week or so while they tried to find a way of achieving this. Unfortunately, it looks like they didn't succeed.

 

Well then they would deserve the fiercest criticism because it's not like they didn't know in advance what the US emission requirements were. If they advertised an engine at a specific output in the US without first establishing if it was possible then they are stupid. This is of course hypothetical but it's about time we knew the truth (Statements of great obviousness # 2345.1)