pelucidor

Imagine a TV news exec who reads car magazines, sees this story in several of them a month or two from now and decides to push it on a slow news day to 'protect' their viewers from Mazda's repeated false advertising (remember the Miata).

Do you remember the totally false 'unintended low-speed acceleration' story that singlehandedly and overnight almost killed Audi in the USA for many years? It eventually (years later) turned out to be people hitting the gas instead of the brake pedal and blaming Audi for the resulting low speed crunch into their garage wall. Look at the damage that can be done by an untrue story if it gets on TV...

eccles

Oh yeah. Watching from Down Under, it was blatantly obvious right from the outset that morons were simply hitting the wrong pedal. We watched with growing amazement and a sense of "Only in America" as it got as far as it did.

BillK

Now imagine the same news exec in the general manager's office being told they will not, repeat not endanger automotive advertising revenue and thus the story is spiked...

rpm_pwr

Actually, funny you say that. My uncle had an Audi with electronic throttle. He was sitting at the lights one day when something went very wrong and the throttle stuck wide open. He said he stupidly didnt think the shut the car off as it torched it's tyres through a red light narrowly missing traffic.

As for the OZ-spec 8's. Yep it's Euro3 compliant. Australia is slowly converting to ECE compliance, thus all power figures are quoted as ECE and cars have to meet Euro 3 by 2004. Mazda complianced the RX-8 as an 04 compliant car, thus they will not have to recomply it here next year Unlike, for example, nissan. Australia is slowly shifting away from US-style emissions requirements.

On this subject though, does anyone think it's odd that California got 250ps cars? They have emissions standards that would surely leave Euro3 well behind yet they got Japanese power levels!! Despite the fact that they are getting the same maps as the most generous country in the world in terms of emissions. It just doesnt line up.

Let's say for a moment that Cali emissions requirements were somewhere between Euro3 and Euro4/5 (which I thought they were). Experience tells us that power is inversely proportional to tailpipe standards. Thus you would expect power to be no more than about 235 probably closer to 230. That would then line up perfectly with the RWHP numbers people are seeing wouldnt it?

So my theory is that everyone in the US is geting Cal. spec cars and hence less power. Well, it's just a theory anyway

-pete

TurboSE

The graphs might have shown the auxilliary ports opening at 6000 rpm but that does not mean that the port sleeves rotated all the way to open the port fully. It could be partially open causing airflow problems. Ok, having spoken to someone at the local dealer I am convinced there is no such thing as a mileage switch or some sort of ecu chip replacement at a service interval. He said his service tech trained by mazda would have known for sure.

5Gen_Prelude

The problem with that theory is simply they already did that when they reworked the Miata engine a couple of years ago. I can't imagine they would make the EXACT same mistake AGAIN causing them to offer the same options as they did with the Miata owners.

Elak

I've read a couple of posters who say they feel the car losing steam around 7500 rpm. I went to a nice deserted track this evening and played around with the red line in 1, 2 and 3 gear. I must say that i can't feel any power loss 1 and 2. Red lining 3 takes some effort (=length of track) but the air friction building up at speed^2 explains that I guess.

I don't doubt that the dyno's get the values they are in the fixture, however if the HP curve went flat after 7500rpm, wouldn't that be quite noticable to a driver (with friction building up square)? What does your butt-dyno tell you?

/Elak

Lensman

Hercules has stated elsewhere that he feels his engine isn't performing as expected above 6250rpm.

neomicro

Been watching this thread for a while now. I did the recommended break in on my car, not above 6,000 till 600 miles. Then I added my own break in, not above 7,000 till 1,500 miles. After this only short trips up to the top. I have already done two oil changes on the car. Not that it needed it, but I figured if they recommend a 600 mile break in, it would not hurt to change the oil at 600 miles. the second was more to put it at an even number for easy reference as to when the 2,000 mile oil changes are going to be due.
Now that the car is over 2,000 miles, I decided to check out how the power delivery felt as it accelerated through its upper end. I ran the car in 2nd and 3rd up to 9,000 rpm and I have to say I did not feel the loss in power. I felt the car building power all the way up to around 8,500. I had a passenger in the car who verified my findings.
I think it is time for me to find a Dyno and see what this thing is putting to the ground.
Anyone know of one in the East Bay area of San Francisco. I am just North of Berkeley. I need to find one anyway so I can start tuning my RX7 when I finally get it back from the shop.

RX8-U-UP

I too have been experimenting with red line, primarily in second. I havr the same conclusion as Hecules. At or about 6200 RPM there is a hesitation, and then just linear response to additional RPM's. This is not 40 additional HP kicking in, as was noted in some magazines who tested high power cars that were working properly.

I believe that as a group of owners we need to all work together to try and pinpoint where the loss of power is or the flat line response starts. We should all feel something more than a hesitation at the 6200 to 6300 RPM transition. if this is where we all can conclude we don't feel boost then there is really only one explanation, third port mechanically or electronically failing to operate correctly.

I am not in favor of letting my local Mazda dealer machanic take my car out and repeatedly red line it to come back and say it feels okay. They probably have less knowledge of what to expect from this car than we do.

As a group we need to go out and perform open road red line test, paying extreme attention to RPM and engine feedback. My best results is to linger in second at about 5500 RPM, and then when I get the chance accelerate while monitoring RPM in conjunction with engine noise and feel. You will have to turn off your stereo and A/C for best results.

We need to post our observations and results back to a single thread for compilation. Then we as a group need to find a way to get heard by Mazda Corporation and not a lot of individual dealerships. It is my experience that dealers and their mechanics with this type problem are institutionally indoctrinated to not recognize or in any way sympathize with the customer over optimum performance issues.

I believe the most unbiased and independent info we have so far are the dyno's, poor track times adds the worst variable of all, the driver. This car is performing, and I think that a lot of the owners who have now driven it more than a thousand miles know, it is not performing as advertised above 6250. There was an advertised kick (mock super charger affect) (40 additional HP kicking in between 6250 and 8500 RPM) at this point I just don't feel or hear it happenning. Just my thought on this subject. Individually I feel we don't have a chance, but as a group I think we can get to the bottom of it.

Lensman

Excellent post!

Elak

Ok, the hesitation at 6250 is consistent with the dyno's, however between 6500 and 7250rpm the graphs show nice linear build-up of power (15-25bhp) .

Judging from your text you agree with this sensation, however what you expected was a 40bhp turbo-kick? I've eagerly awaited this car for 3 years, and believe I've read quite a few reviews and descriptions, however I can't remember anyone describing a turbo-kick. If the turbo-effect is more that of a low preassure turbo, then a linear buildup of power should be expected, right?

If all those 40bhp came around 6500rpm (at 165-170bhp according to dynos) then you would already have reached the peak power, way before 8500rpm.

The dynos get what they get, but is the people reporting lack of power mainly a question of expecting a high preassure turbo-kick and not getting it?

/Elak

RX8-U-UP

Elak, Your point is well taken, but I was in no way expecting a turbo type response. There appears to be nothing more than increased RPM = increased speed (with a gurgle at 6200, like it thought about doing something). I did and do expect a boost of power since developing 40 additional HP in 2000 RPM should and would provide this expectation. It was descibed as a mock super charger effect, in this 2000 RPM band. The loss at the rear wheels should be across the whole spectrum, not all in its optimum power range. Don't get me wrong, I love what I got. I just feel we were promised more, and others have gotten more from this car in testing.

neomicro

Just took my car out again and did several runs 1st gear and 2nd gear. I think I can feel the hesitation you are talking about but I only noticed it if I did not have the throttle pinned. Although I did not notice the hesitation when smashing the gas pedal, I did notice is that right around 7,250 I felt and additional rush of power, not only felt but heard. Windows down, it sounded like a little mini turbo rush. I started rolling in 1st at 5,000 rpm and just floored it, 1st and second. DSC and Traction control off, AC and Stereo off.

I am still looking for a shop with a Dyno where I can do tuning on my FD, and I still want to run my 8 so I know for sure what is going on with it. My FD until this year has always been stock, so I have had no need for tuning. I will check over in one of the forums specifically for RX-7's and see if anyone knows where to go in the Berkeley, San Francisco area.

Elak

Ok, so if we stay with the sensation of acceleration, what are you expecting? If not a turbo-kick, were you expecting to be further pushed down in the seat (acceleration increase) above 6500rpm?

With air-friction building up square (I believe it becomes the main friction component at 25-35mph), I'm not sure you can expect to feel acceleration increase except in 1'st gear. In 2'nd you are already at 40-60mph at the relevant rpms, and achieving maintained acceleration (keeping the butt preassure up) seems to me to be more in line with a linear power build-up.

In my subjective opinion this car is much more powerful than my previous (210bhp) car, so unless it too was over-speced, I'd say the RX-8 I'm driving has more than 210bhp.

/Elak

P00Man

"poor track times " rx8-u


i recall someone posting about a "freind" or what have you getting a 14.9 at the 1/4 mile strip, he also said that his freind has the time slip to prove it, perhaps we could ask him to scan the strip and post it, cause i really dont think a car putting out 180-190 hp to the ground could get such a time

RX8-U-UP

That is what is so deceptive about this problem or the perception of a problem. At 210 HP the new Low Power Renisis 13B rotary is more powerful than any other N/A 13B rotary that has been produced. From the original and each succesive generation of RX7 N/A rotaries we found and came to accept that a low power and low torque small engine can still produce speed, pick up and intense exhilaration while driving. This makes it very hard to objectively evaluate an N/A rotary that produces 247 HP. With my limited experience with rotary powered vehicles, I believe that a rotary producing 210 HP would feel and give the perception in every way as being faster and more powerful than a 210 HP piston driven engine to the driver. Objectivity is tough, when there are no comparisons for the new renesis rotary. I respect your tempering of my sometimes slanted posts. Got to go driving. Zoom, Zoom.

Genom

I know the technical validity of this is probably squat, but acording to my dealer (whom I just went to see) the engine produces 247HP without all the extra crap of belts, AC, alternator, etc.

I said I thought he was full of caca, and he promised to ask Mazda about it, but I dont think he will. I'm still waiting for oficial word from Mazda to be honest, but thought I'd post a bogus opinion anyways :D

Lensman

Even if it is true then it's true for all cars and the dyno measurements for other cars are as expected whereas those for the RX-8 are not.

Elak

Sorry RX8-U-UP,

I hope your not getting annoyed with me, but I'm just genuinly interested in the discrepancy I sense between what is registered on the dynos, and what I experience when accelerating my RX-8.

Since you and Hercules have a different perception of the acceleration sensation, I'd like to know as much as possible about about your experience and also what you expected (may look like I'm trying to corner you but this is curiosity).

Btw I do have the high power engine and my previous reference to my old 210bhp, is just in reference to the current dyno indication that the high power engine only produces ~210bhp on the flywheel.

Simply put, my observations are:

#1 I can't feel the power curve of my engine flatten out around 7200rpm as the dynos suggest.

#2 Compared to my previous experience of 210bhp piston engined car I'd say the RX-8 is more powerful.

As a single observer I understand this has little relevance, however if more drivers come to the same conclusion, then that may be circumstantial evidence that the dyno-sessions are missing some parameter in their setup. It doesn't say anything about what the actual power is, only that it doesn't behave like on the dyno.

/Elak

ChurchAutoTest

Couple of comments:

1. Unless you are a professional racer of some renown, your butt is probably quite inaccurate. Human beings are quite good at resolving changes in acceleration (known as 'jerk'), but very poor at resolving actual acceleration levels. And on the street, there are constantly little changes in acceleration taking place due to bumps, shifts, etc. that can confuse your butt. We're very fond of saying that "The butt dyno lies". I just had a racer the other night tell me that his car felt slower, yet he turned his fastest lap of the night in that "slower" car.

2. The hp still peaks above 8000 rpm on the RX-8s. Its just that the torque curve falls off much faster than it should for a 247 hp car. There should just be _more_ under the curve than what we're seeing.

3. Instead of using the butt dyno to attempt to feel what happens on the street, why not instrument the car? At a minimum, use a G-tech. For those in SoCal, drop me a line and you can stop by the shop and use my Vericom which continuously monitors G-force during acceleration. You can see just how much acceleration falls off after 6000 rpm instead of guessing.

SC

Elak

I'm sure you'll get takers on that offer. Sadly I'm in northern CA.

I couldn't agree with you more on the absolute acceleration inaccuracy, however I'm arguing that you would have an acceleration decrease above 7200rpm if the dynos show the whole truth. Both dyno's I've seen on this board are pretty much flat power after 7700rpm (after a dip around 7200rpm). True - one displays a peak of 5bhp just around 8500rpm, but it is flat before and after. Constant power with friction increasing as rpm^2 (assuming same gear) should result in an acceleration decrease.

Enough to notice with the butt? Can be questioned, and you're quite right I'm no race driver. Anyway be sure to post results from whomever is the lucky taker of the accelerometer.

/Elak

RX8-U-UP

Sports Car International May 2003 outlines the process: “ A mock supercharging effect derives from the sequential operation of the three intake ports on the high power version. Each port primary, secondary and auxiliary-come into play at a different stage of the induction cycle. The secondary opens at 3,750 rpm, the auxiliary port at 6,250 rpm. A variable valve in the intake tract opens a straight induction path into the auxiliary port at 7,250 rpm. Engine timing changes with each induction stage, so that breathing recalibrations are seamless to the driver. This motor lives to spin at 8,500 rpm.” This implies to me the continuous building of power to the 8500 rpm point. What does this mean in respect to the dyno charts that are currently on file? Are we seeing all of these milestones on the graph? Just a few questions, since we have the dyno experts on the thread.

joelsrx8

Your dealer would be incorrect. SAE NET horsepower (what the RX-8 HP is quoted in) is measured with the items connected that are required to run the engine such as alternator, water pump, belts, exhaust system, etc. A/C is probably not included but that's about it.

The old "SAE GROSS" horsepower that is typically quoted for cars that were measured pre-1972 did not have all of that stuff attached. That's why they typically had higher horsepower ratings for the "same" engine

Here's more info if you'd like

http://neptune.spacebears.com/opine/horsepwr.html

Genom

Hey, I told ya I thought he was full of doodoo. Didnt beleive a word of it myself since it would be VERY misleading and stupid to do something like that. Just thought I'd add a dealer story to the pile while we wait for a real reply.