jonalan

In the performance section, it also still says "...with 247 horsepower @ 8500 rpm..."

My guess is that they are just updating the website, but I'm sure this will just feed the "controversy" frenzy.

rotarynews.com

Answers are coming soon... But I think in the other thread, Paul Yaw has hit upon the answer: AF Ratio being richened by the ECU.

Speculation: The ECU in the 8 is very high tech, but was not designed with chassis dynos on the mind... so the shock, load, and heat of the dyno run makes the ECU dump fuel into the engine to protect it, there by decreasing the horsepower and torque.

Here is my challenge to youse guys:

Dyno with

1. A wide band O2 Sensor

2. A Mazda Dignosis machine and monitor, in real time, the sensors (air temp, AF ratio, etc)

3. A cooler facility

4. The report back on the results before Mazda has a chance to :D


-----------------

takahashi: Mazda moved the specs onto the "normal" car section http://www.mazdausa.com/MusaWeb/disp...ehicleCode=RX8

ZoomZoomH

iTrader: (1)

an ECU designed to PROTECT the engine? AMAZING!

DocHolliday

http://www.mazdausa.com/MusaWeb/disp...ehicleCode=RX8

The specs seem easy enough to reach from the main page. It took me 3 clicks to get to that page.

ChurchAutoTest

For owners residing in Southern California, I am willing to provide a free dyno session to generate some more data on this topic.

We use a Dynapack chassis dyno, which is a bit different in that we remove the drive wheels and attach the dyno directly. This allows us to control load more precisely. The readings are usually somewhat higher than on a Dynojet (about 10-12 hp) because the load of the wheels isn't there.

The dyno also datalogs a MoTeC wideband O2 sensor, manifold pressure, etc. Additionally, we use a OBDII scantool to monitor intake and coolant temps to ensure consistency and real world relevancy.

We have dyno results from other cars in the same power range (in particular, many Honda S2000s which have similar driveline, power curve and torque delivery characteristics).

If a person (singular, can't be doing too many free service) would like to try his/her broken in car on the dyno, please feel free to contact me.

Shawn Church

Church Automotive Testing
20950 S. Normandie Ave.
Suite K
Torrance, CA 90502
310-787-7123
spchurch@earthlink.net

seikx8

How's about the first person hit the 5000 miles mark? I only got 1200 miles. I would be interested and planning to take mine to a dyno anyway. Perhaps some discount would also work if more people interested? :D

ChurchAutoTest

I'm willing to entertain other scenarios.

SC

p.s. - someone with about 2000 miles will be coming by in the next week or so. We'll have to see about higher mileage down the road.

bern

I've should've stated and/or wrote it the following way:

".... their own marketing-PR and/or legal departments....."

I didn't mean to imply that the legal department was clearing anything.. on the other hand, marketing and PR might want to handle this situation delicately, even if it is just an ECU map thing... They may need to figure out how to desiminate the info to both consumers and dealers... and answer questions as to why this is happening, and why no one told anyone about it. Remember that dealers are Mazda customers too...

I was just saying that unfortunately, major corporations now-a-days just have to be very careful on any point... there is always one or two people who will have major issues with things, no matter what happens or is said..

Again I'm not implying that any of this is going on, it's just my own personal hunch.

-Bern

chiketkd

iTrader: (5)

Around the middle of last week, I sent Mazda the following message:

"I'm a sportscar enthusiast who currently owns a 2000 SVT
Lightning and just came back from attending the MazdaRevitup stage 14 event in DC. While at the event, my wife and I got the chance to check out the all new RX-8 and I plan on purchasing one in the coming months.

However, I have a concern which I first saw addressed by Sports Compact Car in their May 2003 issue - the 6spd manual RX-8s not producing their advertised 247hp. Several new owners on the website www.rx8forum.com are also experiencing low dyno numbers ranging from 174-184hp for their 6spd manual cars.

Now I'm not looking for the standard, blow-me-off "It makes
247hp at the flywheel" type of answer, as I know enough about cars to not accept a 25.6% drivetrain loss in a car built after 1980 w/ a 6spd shifter and a carbon fiber driveshaft. You could earn the respect of a potential valued customer with your response."


Mazda e-mailed me back with the following response this evening:


"Thank you for contacting Mazda North American Operations. I appreciate the opportunity to respond to you.

In regards to your question, Mazda is aware of the reports showing that the 2004 RX-8 has lower horsepower than advertised. Currently Mazda is looking into these reports. Until further research is done on this matter, Mazda is not able to comment on these reports. Please know your comments have been documented and are continuously reviewed by the Product Planning Department in an effort to provide only the most
exciting vehicles.

I am pleased to hear of your enthusiasm for the 2004 RX-8! We would love to have you and your wife as part of the Mazda family!

Again, thank you for contacting Mazda. It has been my pleasure to assist you. If for any reason this response has not completely
satisfied you, please feel free to reply to this message. You may also contact our Customer Assistance Center toll-free at 1-800-222-5500.

Sincerely,

Heather Drake
Specialist, Customer Assistance E-Business"


Well Mazda is aware of the problem at this time and we should all be hearing something from them officially in the coming months. It wouldn't surprise me if it was a "quick fix" like an update to the ECU (a couple members mentioned that the cars are shipped from Japan without being CA emissions compliant, but at the port technicians put in a US spec ECU).

rxtreme

iTrader: (1)

Shawn-

Please make sure to post the results of your test on the RX-8 you have coming in, either here or on TOV (vtec.net for all you Honda haters).

For those of you who don't know, Shawn Church is about one of the smartest guys you'll ever meet---on the net or in person. He knows more about automotive engineering than most people. I know he'll make sure that the RX-8 is tested fairly and that all variables are measured and taken into consideration.

RodsterinFL

You don't suppose that the engines are really all 4 port or something instead of 6 port do you?

TybeeRX-8

The new "Wired" has a nice two page spread on the 8 and it still says 247hp. I don't think thye would keep advertising it if it wasn't true particluarly given the Miata fiasco.

Sputnik

Were are very sure that this is not the case. We see the 5th/6th ports kick in on the plot, and we would not see the overrich situation.
Ads are sent into the magazines a LONG time in advance. Chances are, the magazine had that ad before the first RX8s hit these shores.

---jps

ChurchAutoTest

Will do. If time allows, we'll do a quick trip around the block and note normal operating temperatures (intake and coolant) and try and duplicate those as closely as possible on the dyno. I'll also provide comparison plots with other RWD cars of similar rated power levels (Honda S2000, Nissan 350Z, etc.)

And thanks for the kind words

SC

Efini 8

does anyone know the model, brand, and type of dynamometer used in the results that show lack of power? has anyone looked into any dyno graphs made by Japanese owners/tuners? remember they are rated in PS - which is 1.25 hp. If someone can find a Japanese dyno graph, we can narrow it down to just a US Spec problem, most likely the ecu which is different in comparison to the JDM Spec.

Gord96BRG

We've already seen a 2000 mile car dyno'd and it wasn't much different than the 800 mile car - and it's been suggested that the engine isn't broken in yet as far as making max power at 2000 miles. Unless you are going to dyno the exact same car at around 5000 miles (for which a dyno run at 2K miles would be an excellent baseline and comparison), then another dyno run on a 2K miles car might be a waste of time... we (the RX-8 community) might be better served by someone taking advantage of your offer with a car with more miles on it, or waiting until someone gets to 5K before putting it on. Just a thought.

Regards,
Gordon

wakeech

um, dude, i think you're thinking of kW (which is closer to 1.3hp/kW).

a ps is about 0.93hp IIRC

beaner

I would also note that all of these dynos have been done in the hot part of the summer. One of the dyno charts specifically said that it was 95 degrees, most likely high humidity.

It is common knowledge that cold air basically contains more compressed oxygen, which makes much more power when it burns inside an engine. Hence...cold air intakes, etc. Just a cold air intake can add 10-15 horspower on some engines.

I notice an immediate power increase in my car on a cool (sub 70 degree) low humidity day, especially this summer, when one day it is 90 degrees, and the next it is 70. This is also why fuel economy goes down in the winter, because every car suddenly starts burning more fuel, but you get a little better performance.

I don't know how this translates on the dyno, but I almost guarantee you will get more horspower on a 60 degree day than on a 90 degree day.

The manufacturers must have some way to reconcile this issue...but a simple answer could very well be that Mazda tested the engine in the winter time, and all of you guys are testing it in the hot summer. I betcha when the manufacturers test them, it is in a completely controlled environment. Maybe someone out there has more specific knowledge on this and can comment.

RomanoM

Most dyno software is capable of correcting for climate conditions.

NOT saying it was done in the cases posted on this board, just that it can be done.

cjb80

Hey Shawn!!

Anyways, I hate to burst the bubble for you guys, but chances of the ECU leaning out after X miles is slim. After reading this thread, here are my thoughts...

I admit that I am not an expert on rotaries, but it would be hard to make up 30 hp on fuel tuning alone.

In addition being on a dyno wouldn't cause the ecu to freak out and dump so much fuel that you'd lose 30 hp. The ECU looks at several different conditions which determine fuel, but none of these include a little camera to see if the wheels are on a dyno or not... The only potential issue that you would see on the dyno is air intake temps higher than normal. This obviously results in thinner air, and thus less power. The ECU will actually PULL fuel in this case, not add fuel.

Adding fuel to the engine for "break in" is silly, and I find it a far fetched idea.

Last, I am surprised that among the cars tested no air/fuel data was reported, this would be more conclusive obviously. I am not sure what a target AFR would be for an N/A rotary, but checking that out would be helpful. Once again, even if you were running *super* rich (unlikely), a gain of 30 hp is a lofty goal.

I hate to say it but it sounds like Mazda will have to be fixing or compensating you guys somehow...

Good luck guys!!!

Chris

RX-Hachi

The June Best Car's (Japanese car mag) test results of the 250 ps vs. 210 ps versions of the RX-8 seem very odd. Both cars got about the same time for 0-100km/h (0-62mph) and 0-400m (Japan's 1/4 mi.) What's more the 0-100km/h of 7 secs is way off the pace for the 250 ps high power. Perhaps it's not just the US models with a power shortage...

http://www.artex.co.jp/Pages/Car/RX-...03_6-26_03.jpg

P00Man

hmmmmmmmmmmmm once again the plot thickens...

this is starting to get strange...

cueball

It could just be the magazine that tested the cars at the time or the conditions didn't lend themselves to good testing.

On the similar times for the low and high power versions, it could be that the Japanese low power version is a stick, which would alow for increased times as compared to the US spec auto.

P00Man

yeah, there is a low power 5mt option in japan

Sneakyracer

That is a lame excuse, what is equal for both cars is fair. If both were tested in similar conditions.