Fishey

I just wondering what everyone has as far as personal car stats (How your car proforms)

My friends 2004 Manual puts out 170Rwhp and 15.1 1/4mile Gtech skidpad of .93.

What has everyone else done?

6speed8

Well the Rwhp number is incorrect, the '8' doesn't like Dynos, something with the dsc/tc, it senses the front wheels not moving and runs the car in a 'detuned' mode. To prove this just look at the stats of other cars with similar (at the flywheel) hp ratings, like the S2000. The S2000 has 240 engine hp, 200 Rwhp and weighs 2700 lbs. and scoots to 60 mph in mid 5 seconds. The RX-8 has 238 hp at the flywheel, weighs almost 3000 lbs and scoots to 60 mph in just under 6 seconds. Put 250 or so lbs in the S2000 and I bet the 0-60 time would be comparable to the RX-8.

As for skidpad numbers I have seen .88g-.91g in magazines.

There is so much more to a car than stats, but we all fall prey to the 'numbers game'.

Xyntax

So... if I was to dyno my car, would mine be a more precise number because I don't have TCS/DSC installed? What do you think?

Does anyone know of a place here in the Bay Area (particularly San Jose) where I could reliably dyno my RX-8? Let me know. This should be interesting

Gyro

It would be interesting, however you do still have ABS sensors. This is where the RX8 sees wheel spin. The lack of TCS/DSC may not impact the "limp mode" on a dyno.

Xyntax

What's "limp mode"? So you mean to say, if the ABS is disabled temporarily, I might be able to extract a more precise number?

Gyro

Limp mode is a non technical term used around the forum to describe the ECU intervention to certain events.

Limp mode may occur when the engine misfires under hard acceleration. This is a protective measure, over richens fuel to aid in anti detonation as well as retard ignition.

Limp mode also has been seen on a dyno. The ECU sees the rear wheels spinning without the fronts spinning, and even though you defeated the DCS (with a long push on the button) the ECU still "detunes" to compensate. The RX8 is not dyno friendly.

My comment was regarding the fact that your PCM (ECU) may still detune like the rest with the DSC on a dyno. Your car still "sees" wheel spin. It just lacks the equipment to mechanically compensate. This is not to say you PCM wont still try to go into "limp mode", though...because it is designed to protect the engine in an event like the first scenario I gave. Your car still has that feature.

It still would be interesting to see if the Dyno numbers are different. I suspect not.

Ike

Look guys, if the car was really going into limp mode it would be a more dramatic result than just bringing it down to 170-185 whp. This whole thing is now brought up because of a statement that mazda released and I don't think it's much more than Mazda trying to cover their ***. The numbers it's putting down at the strip including trap speed and times, the way it drives, all the dyno results, indicate it probably not 238 bhp and closer to 220.

If you want to believe the mythical limp mode that the RX-8 goes into on a dyno then that's your perogative. But magazines have tested it and can't find any evidence that anything changes when the car goes on a dyno. And there probably is a limp mode on the RX-8 but you would need more wheelspin than you would ever create on a dyno and there really don't seem to be any sensors or ties with that front wheels like has been claimed.

I'm not saying this makes it a bad car, it's obviously not, and most owners don't care about the numbers because they love their car so much which is what really matters. But if you're going to talk about numbers at least face reality and stop talking about this it doesn't dyno well nonsense. I've driven the RX-8 a couple times, I've also driven many other cars with 200-215 at the wheels, and the RX-8 is not making those numbers. That's what it should be making if it were really 238 at the crank.

<awaits the flames>

Ike

Xyntax

I see. Thanks for the info. Are there other cars out there that have the same case as the RX-8?

Gyro

I believ Ive heard of similar issues with the M3

rabinabo

Actually Ike, there's no way to get much more wheelspin than you could on a dyno where the front wheels aren't connected to the back ones? Let's see rear wheels going at fast as possible with the front wheels stationary = wheelspin as far as the comp. is concerned.

ptiemann

Unfortunately IkeWRX seems to be right. The car either has a GREAT loss from the flywheel to the wheels, or Mazda simply lies about the hp at the flywheel.

Look in the tech garage. CanZoomer did some trick to connect the sensor that measures the front wheels to the rear wheels instead, so that all 4 wheels return the same speed while on a dyno.
Thus he circumvented the spinning-recognition or however it's called.

The car isn't any faster then.

I simply accept the fact that I bought a ~ 220 hp car and that's it. It's fast enough for me to get in trouble with law.

-Peter

Kain

Ike Ike Ike. oh how I don't like Ike.

Ike

I'm talking about rear wheel spin, everything I've read (other than the Mazda statement) seems to indicate there really is no feedback to the ECU to determine how fast the front wheels are turning in relation to the back wheels. Even if there is feedback, it's not doing anything to put the car into limp mode. All the evidence points to the RX-8 being closer to 220hp, with the exception of some statement some guy from Mazda made on rotary news during the whole HP contraversey. Unless of course the car is losing, like Peter pointed out, huge amounts in the drivetrain. If that is the case then Mazda has a whole other problem on their hands.

6speed8

If the Limp or detune mode issue is a myth, then please show stats for another 3000 lb car with 220 hp doing 0-60 in under 6 seconds, and please remember there is not much torque and 18 inch tires.

The closest car HP and torque wise is the S2000, which is 250 lbs lighter and does not have 18 inch tires. Put the 18s on an S2000 and add 250 lbs of ballast, I'll bet the 0-60 times would be around 5.9 seconds. We know Honda probably underates the S2000 engine hp. The S2000 is putting aout 200 hp to the rear wheels.

So IF the RX-8 is only puttung out 220 (as IkeWRK and others speculate) it is one fast ride for the HP/Weight ratio.

Rough figures: S2000 240 hp/2750 lbs = 11.9 lbs per hp
RX-8 238 hp/3000 lbs = 12.6 lbs per hp
RX-8 220 hp/3000 lbs = 13.6 lbs per hp
Celica GT-S 180 hp/2500 lbs = 13.8 lbs per hp

No test of a STOCK Celica ever came CLOSE to 5.9 seconds 0-60, in fact most were 6.8 - 7.1 seconds.

How can the RX-8 NOT have more than 220 hp?

ptiemann

Not sure what the weight per hp ratio really says, I think it's pretty irrelevant.

Take a motorcycle and you'll be having a lot less lbs per hp, so what?

I'm quoting CanZoomer here:

taken from:
https://www.rx8club.com/showthread.p...r&pagenumber=3


Everyone should read this thread and particularly what CanZoomer says. For the newbies, he's the one who sells a chip that give you back your missing 25 whp (yes, WHEEL hp)

He doesn't defend his RX-8 as if someone had said "Your girlfriend is ugly".

Ike

1.) Those 5.9s in the mags were done with a pre production car with the j spec ECU.

2.) Trap speeds don't lie (most of the time :p), and 0-60 times aren't as good an indication of a cars HP.

3.) Do you really think Limp mode, safe mode whatever you want to call it is safe if it drops the car a whooping 20hp... it's designed to save the engine/drivetrain and possibly even people. If you think 180hp is safe and 200hp isn't safe then you're wacked.

4.) A stock WRX weighs around 3k, it has the advantage of an AWD launch but in most cases doesn't get more than 170hp to the wheels, it goes 0-60 in the mid 5s with a proper launch.

5.) The Nissan Altima has run 5.9 0-60 weighs 3200 lbs and is FWD with a claimed 245chp, and that's with the disadvantage of FWD. There are other cars I could use as an example

6.) Look up occam's razor.

zoom44

but hymee has seen his freinds car go into limp mode on the dyno, with flashing cel and everything, while testing his cat back. however hymees car does not do it.

Ike

Hey, it may be possible... But there have been plenty of other dynos where the cel never came on. If the car was going in and out of limp mode you would see it on the dyno charts.

Lets examine the series of events...

People get their cars dynoed shortly after release

Dynos range from 165-185 whp

Arguments ensue and people pick a side, the 247hp is true people, and the blasphemers

The blasphemers are somewhat redeemed and Mazda issues a revised hp number of 238 which is as low as they can go without worrying about legal action being taken.

Mazda claims the problem was because of a new ECU fuel map.

Some people still don't believe the 238 hp.

MNA quietly issues a statement about dynoing the cars, and leak some odd looking time slips, some of which were done with the pre production car.

SCC, and Canzoomer try to find this mysterious front wheel sensor that is linked to the ECU, no evidence is found.

MNA execs sit in their offices biting their fingernails trying to figure out what excuse to come up with next.




Now which scenario seems more likely to you?

a.) Mazda fibbed again.

b.) There really is a front wheels sensor and the car is making 238hp even though no one has been able to find it and all the evidence points to the cars making closer to the 220hp range

c.) Mazda has managed to create the most power sapping RWD powertrain in recent automotive memory

zoom44

actually ike it was canzoomer who saw the dyno problem in the first place. he knows and still talks about the problem. that is why he does much of the tuning based on street runs. quick runs on the dyno don't cause it but runs over(i think he said) 5 seconds make it happen.

Ike

I'll have to go back and read the thread more closely when I get time, I thought it was wheelspin over 5 seconds or closer to something like that. I also thought him not doing a lot of dyno runs was more a problem of access to a dyno. but like I said, it's been a while so I'll have to skim over the thread(s) again when I get time.

Ike

Japan8

I'm not entirely doubting the 220hp... nor do I accept it. I haven't driven a US-spec car yet, so I can't say exactly, however...


1) Lack of evidence. You are assuming it was a pre-production car and even then that the ECU was j-spec. It was posed elsewhere... it seems improbable that Mazda suddenly remembers or suddenly learns of EPAII and has to do a reflash in port. This is too basic, too important and something of the level that it has to be accounted for during development for it have been so easily overlooked.

2) Yep... and because of it... you can still have 1) be performed wiith a pre-production US-spec ECU and still get the numbers.

3) limp mode isn't saying dropping 20hp is safer for the engine. Use your head! The exhaust temps from the Renesis are HOT! Running the car repeatedly on a dyno will make for a hot engine and even hotter exhaust system. In order to preserve to the cat. at minimum and likely to just prevent overal overheating. In terms of driving saftey... just the same as the principle of TCS... instead of only having brakes through ABS, now there is also A/F mix and timing retard to use as tools to control the output and application of power.

5) The Altima may weigh 200lbs or so more, but it also has 245hp instead of 238hp or even 220hp. So what was your point?

6) supports what I said about #1 as well...

Elara

Didn't Motor Trend just get a 0-60 time of 6 seconds in that last comparison? Pretty darn close to 5.9, doncha think?

Ike

1.) No I'm not, it's stated in the magazines that the early tests were pre production cars. If you find it so improbable then talk to Mazda, are you saying Mazda is lying and they didn't do anything to the ECUs?

2.) Unless you go through 2 trannys in the process I haven't seen anyone come close yet. But I have seen some 15s in person.

3.) You should use your head, the heat that is created on a dyno is nothing compared to what a car will go through during agressive driving on a street, extended high speeds on a highway, or a track day/autox. Dyno runs are short and easy on a car. Also, if they were concerned with heat I don't think the wheels is a good place to put the sensors... I did say something about the safety of the driver, which you also mentioned, and my point is that a drop of 20hp isn't going to save any driver if they are going out of control.

5.) My point is the car weighs more, has a disadvantage based on FWD, and can run the same times as an RX-8 and will run those times or close to it more consitently. If you think it's the 7hp then oh well, I give up arguing...

6.) Not really, your scenario is no more likely than mine. You claim Mazda lied about changing the ECU, I claim they lied about the HP as a result of them changing the ECU. Whether the 247 was ever correct in the first place doesn't really matter in either scenario.

Japan8, lets not let this get nasty and discuss this like adults, I really don't want this thread to turn into a big flamefest.

Thanks,
Ike

Fishey

Thats what I get in my 208HP Porsche 944s2.. I also managed 180RWHP 182Lbs this on the dyno from my all stock engine at 120,000miles. The same day my friend pulled 170 the dyno had a great ventilation system I would say a good 10 industrial fans..

Japan8

1) Odd as it seemed like it took forever to see a review come out. But I am not in the States, I don't have a subscription... just whenever I can pick one up or catch it on the mag's web site. What point is there in using a pre-prod unit?? Mazda has less issues of timing to worry about in releasing the 8 than other models in other market segments. Am I wrong thus far? Maybe Mazda did indeed use pre-prod. units... and someone should be fired for it. It just didn't seem like that to me, nor did it say that in the articles I read on M/T, C/D, R/D...

2) I read about the runs at the drag strip... two trannys is only the beginning. This kinda thing makes me worry about how it will hold up with FI added.

3) & 4) You neglect the lack of air moving on a dyno. That plays more than just a passing part in cooling the engine, exhaust, etc. The sensors aren't heat sensors, it's from the ABS/TSC/DSC systems. The wheel would be the place to detect wheel slippage, correct?

Even read on BMW's interntional site... limp mode isn't a figment of people's imagination. BMW has it on the 3-series and M3. The M3 CSL is reporgrammed to give better launches and allow you to take the care closer to the limits before the computer cuts in. It's not unreasonable to think that Mazda employed a similar system on the 8

What about the CEL's that many (not all... I know) people have been getting when they try to dyno their cars? There's gotta be something to that...

5) Nah you're right... 7hp is just on the edge of you can actually notice/feel a difference.

6) I think what we have here is... Mazda is full of BS. Now what the exact details of it are... well we can come up with equally plausible senarios all day and they'll get us no closer to the truth...

No one is trying to get "personal" here. This is online forum stuff... I don't take it so seriously... just a good source for info and some mental exercise.