73JPS

I am sure this is a stupid question, but is there any chance that in the heat of the moment these cars were dyno'ed with the DSC still partially engaged?

Shamus

Yes, if memory serves one of the very first runs may have had the DSC partially on. The DSC and the other electronic gee-gaws on this car give me some pause about the dyno results. Like the throttle by wire, I've seen a few people suggest that a throttle position reading should be taken during a run to verify that it's really wide open, but I don't think anyone's done it yet.

By the way, nice JPS Europa. A buddy of mine has a beautiful JPS that looks almost the same. Beautiful little cars, and 1,500 lbs wet.

cbj

Just wanted to say that it's nice to see RN & Shawn lending their expertise to this problem and I look forward to reading the results as this gets sorted out.

rotarynews.com

This will be somewhat offtopic post, and I'll probably just be adding gasoline to the fire here... and in fact this makes things more confusing..

Found some HP calculations and calculators on google... Results very greatly, as true calculations depend on a ton of variables that these calculators don't take into consideration.


http://www.battleoftheimports.com/cl...battlecalc.htm sais:
RX8 which weighs about 3180 pounds should complete the 1/4-Mile in about 14.9 seconds, if you can produce about 190.00 HP at the wheels, or about 247.00 HP at the flywheel.


http://www.mustangworks.com/analyzer.html (yah yah..) said:
Best 1/4 Mile ET: 14.9
Best 1/4 Mile MPH: 94.3
Your car weight: 3180

Peak Horsepower: 190
Average Horsepower: 208


Conclusion, even with track numbers and time slips, it will be hard to calculate percise HP numbers.

bassik277

Then theres also an option where you input your:

1. Vehicle Model
2. Vehicle weight (w/drive)
3. And Quarter Mile Time

And it calculates your hp based on that so i entered

1. Mazda Rx8
2. 3200 (estimate)
3. 14.9 (Road and Track)

And here is the response i got:

Horsepower Based On 1/4-Mile E.T.
Your Mazda Rx8 which weighs about 3200 pounds should complete the 1/4-Mile in about 14.9 seconds, if you can produce about 191.20 HP at the wheels, or about 248.55 HP at the flywheel.

zoom44

i'm surprised to hear that bwob is purported to have said something like that. do you have a link? as you can see in this link to a search of his posts he hasn't posted here in quite some time and if you read thru the posts there is no discernible argueing with him.

Shamus

Here's the thread where he mentions the RX8 forum at Miata forum...

http://www.miataforum.com/ubb/ultima...=012624#000002

It doesn't sound like he was REALLY offended, but maybe a little, and of course we don't know what sort of private msg or emails were sent his way.

zoom44

ahh so people who didn't know who he is (like myself when i first saw a post of his) or people who knew who he was supposed to be checked him to make sure who he was(and not just some anonymous person grabbing his moniker) so that his info could be relied upon. sorry if bwob had a problem with someone trying to authenticate a source and i hope he does indeed post his thoughts in here again when he has time. it would be most welcome by many of us here.

thanks!

73JPS

... wow... that was a mouthful...

zoom44

:o yeah i get wordy sometimes:o now back to the actual topic!

BillK

Don't be too hard on Mazda; if you call the 800 number for any car company you're going to get someone in a call center making $5/hour who only knows what's in the scripts before them and any further information (like that above) is probably an ad lib to avoid sounding clueless. (With the end result that they of course sound more clueless than ever...)

rpm_pwr

Apologies for going OT here.

https://www.rx8club.com/rx-8-discussion-3/rx-8-mechanical-prototype-caught-road-109/

Is where I pulled him up on the 280 vs 250 thing.

https://www.rx8club.com/showthread.p...5&pagenumber=1

Is where he mentions the "pair of specifications" (referred to on the miata.net post. People do question him on it, but it hardly reads as rude does it? I think it was all pretty mild given on a few people knew who he was.

Nevertheless with the benefit of hindsight, he was spot on (no surprise!) and we are still *yet* to see a 280ps factory rx-8.

-pete

MP3Guy

Hi Guys,

I've been lurking here for some time, and I enjoy your posts. As the owner of an MP3 Protege, let me tell you about my break in experience. I own the car because I do a LOT of driving, and I need something practical and economical, but I'm a dyed in the wool car nut who craves lateral cranial fluid displacement every day I drive. Otherwise, the car is not worth owning.

I trust my credentials are in order!

When I first got the MP3 I couldn't figure out why my mileage was so bad. I couldn't beat 22 MPG no matter what! It wasn't until I hit about 10,000 miles that I finally obtained 30 MPG, which is what a silly *** Jap four banger with 140 horse SHOULD get. But it sure took time. Credit the tight production tolerances on these new engines for that.
I now have 25K on the odo, and the engine is looser and stronger than ever. It revs much easier than it did before, and it's like owning a work in progress. Chances are, the RX-8's need some time down the road for everything to settle in. This car had a very long time in development. I first saw the 8 at the NY Auto Show three years ago (albeit a prototype with push button start, etc.) so I doubt there are any surprises lurking. So give it a chance. My feeling is the cars given to the magazines were probably a bit "massaged" to duplicate the experience of a broken in car.

However, I have been wrong once or twice in my life. Well, maybe three times.

RacerX7FB

What mileage do you have on yours cars before you all eagerly put your cars onto a dyno..and how was it driven? Perhaps being RWD the actual drivetrain loss of 30% is more realistic than 15 to 17%? The only way to accurately find that out would be to dyno the engine in the car at the wheels and with the engine out of the car as well.
A properly broken in rotary engine will produce more power across the engines RPM range and will have a longer service life. This means no revving pass 4000RPM for the first 500 miles and from there up to 1000 gradually increasing the RPMs but NEVER approaching redline. After 1000 miles short burst towards redline for another hundred or so miles.
It would be fun to stick an 8 with my near stock 20 year old FB with over 160K miles on it, because of your unwarranted desire to produce big power numbers right away.

billdo

I find Mazda's reply that "we don't do the test, those are not our numbers" kinda shady. It looks like they are searching for a scape goat with that reply. I mean, hello, they have been R&D'ing this engine for years now, and they dont know the numbers it puts out..yea..sure. I hope this isnt the case though, because crediblity is tough to get back once it's gone.

Shamus

I think they are talking about the fact that a few guys in the US getting 'some' numbers on different dynos on different days is not something that they feel comfortable commenting on, and that's perfecty understandible.

They ain't gonna use our research to make a decision or determination of a problem. They'll be doing their own research.

MP3Guy

http://www.sportcompactcarweb.com/ed..._technobabble/


Looks like there is an explanation, after all. [COLOR=darkblue]

Keeper

A 30% drivetrain loss on a 2wd vehicle would be horrible even for an AUTOMATIC.

A 200hp auto Eclipse GT dynos at about 150-155hp to the wheels (a 20-22% loss). A 200hp mt Eclipse GT dynos at 165-170hp to the wheels (a 15-17% loss). Obviously dyno numbers vary depending on conditions and the type of equipement used, but that's a pretty accurate assesment of what the cars put out stock.

The RX-8 is supposed to put out 50 more ponies than the Eclipse, yet it's only putting 10 more hp to the ground.

The problem could be any number of things, but drivetrain loss isn't one of them. Do not fool yourself into thinking that the numbers being put down are "normal" for a 247hp engine.

Shamus

The greatest thing about debates like these is that we're all factually un-armed at the moment.

None of us knows what IS or ISN'T part of this equation yet, so ruling out something that clearly COULD be playing a part in this situation makes little sense.

Spin9k

In response to my inquiry to Mazda regarding the HP controversy, I received this reply on Friday 8/7:

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

In regard to your inquiry, Mazda is aware of the comments
floating around on the Internet regarding RX-8s not meeting
the posted horsepower rating, and we are looking into the
matter. However, we stand by the current states power levels:
247hp for the manual transmission cars and 207hp for the
automatic cars.
...

...
Again, thank you for contacting Mazda.

xxxx xxxxx
Specialist, Customer Assistance E-Business"

Lensman

This is GOOD!

1. Mazda have officially confirmed that they are aware of the issue: therefore they'll have to prove it's not an problem, fix it or compensate owners. I presume they are legally committed now that they've acknowledged the issue?

2. They intend the cars to match the stated power outputs: therefore they can't get out of this on a technicality if there DOES prove to be a problem.

However: if it was an ECM mapping issue and deliberate then don't you think they'd have simply said so by now? I would have.

Sorry to speculate again. I know that a lot of people are getting sick of idle talk but feedback from Mazda is quite a milestone.

DMRH

I think we should adopt a "wait & see" approach.

However, we should also not allow Mazda to drop the issue either.

Level headed approaches are whats needed...........

rxeightr

This e-mail from Mazda also means they did not purposely detune the RX-8's at port to meet long-term emissions.

RX-8 Zoomster

Good article. It's great that Sport Compact Car measures the HP at the wheel during their review tests. However, when they tested the RX-8, the measured wheel hp was inconclusive because of the defective engine (ports not opening).

I do not know if Sport Compact Car has done a review of a "fixed" RX-8 since that last test, and has provided their "conclusive" rating for the hp at the rear wheels.

Xavier

Hey, new poster here

What we all need to think about is, the fact that the two engines in each version are IDENTICAL. There is no CAI, no turbo, no mods other than your right hand.

And yet, we get a 40 hp increase? Granted this IS a very high revving engine, but 40 is still too much. This just immediately jumped out at me because they are the same damn engine yet you get waaay too much for the MT. Looking at the specs I said to myself "why in the hell would you buy the AT if the MT is the same price?!(almost)"

Im going to make 2 suggestions for solutions
1.) Mazda wanted to make buyers of the MT who are always performance-minded feel special because they are making lots of HP. Im betting they are suprised as hell that since the first few RX-8s are released in the US, we already threw em on a dyno.

2.) Theres a mechanical explanation. Im betting on a combination of 3 things:
ECU Remap
Break in
Lack of AIR on dynos.

Lack of air seems to be omissed from many of your arguements. But lets not forget how the RX-8 is designed. It has the 5 point intake system, with a generous intake area. Now on a Dyno this thing will be SUCKING AIR, especially at the mega Rpms the 8 can get to. Its quite simple...

The volume of air is not sufficient at very low speeds or when the car is not moving. This explains the lack of low end power and torque.

I suggest you find a bunch of fans and put them aimed at the car when dynoing. This will at least try and simulate the volume of air this car is going to take in at driving speeds.

Autos are horrible on performance, yeah. But on similar cars like the RSX, the drivetrain loss is minimal. A 25%+ loss is UNACCEPTABLE.

Mazda is obviously trying to dodge their way out of this. Given their history with the Miata, im doubtful.

Now I know test results vary but Im looking at the consumer guide results for the RSX are as follows:
Type - S (200hp, similar weight etc) does 0-60 in 7.8. Again thats their test, not what acura says.

Now most articles I have seen claim the AT does a few tenths faster than that! What? Its putting down the same if not less power than an RSX MANUAL and its faster? No.

fishy, is it not?
Im not in the market for an 8 right now, but nissan just sold another Z if they dont fix this issue within the next few weeks.