mobilezen

I'm just curious if there is a range of horsepower the factory has to build to spec. There probably is but my overall curiousity is how low (such as -10) or how high (or +20 ) they could deviate from the posted spec on their white papers. Hope this makes sense.

DOMINION

Rxdriftingaction

have no idea

sjt

how can one tell... from what I've read the 8 doesn't get along with dynos very well.

ChrisW

I read somewhere that European Homologation requires that all cars produced are within +/- 2.5% of the published horsepower figures. If Mazda can achieve those kind of manufacturing tolerances for European cars then I guess they can for other markets too.

Of course these manufacturers measurements will be done under very controlled conditions with very precisely calibrated equipment. Dyno reports posted on here will be done at a wide range of temperature, air pressure, fuel grade etc, so will vary by much more. And then there's the cars with stuck ports, fouled plugs, dodgy cats....

marcj1

There was recently a thread about why Mazda chose to restate at 238. Someone speculated that Mazda was confident that even the low end of the production line would fit within whatever the legal range was. You question, regarding what is legal is answered within that thread.

Frank Patrick

There is NO_WAY the 8 is a 200 plus HP Car.

marcj1

Do you mean at the wheels?

reddragonmd

Seems to me there is a sig loss to the wheels of power if in fact the 8 does make in the realm of 238HP crank.

My question is, if htis is in fact due to detuning due to emissions crap, is it a rotary specific thing? Because it sounds like 1 of two things is going on:

1.Mazda way overratted the rx8. Saying it makes +/- 238HP crank when it fact its making about 210 crank.
2. The rotary engine needs alot more tweeks to meet strict emissions standards, which resulted in a huge HP drop. Otherwise you would see alot of other cars coming out, that has to meet the same emissions rules, seeing a huge drop in HP.

Im sure Mazda is mainly to blame, they overratted it before they found out if it would meet emissions. Is that why the 350z was rated at 280HP before it came out, and dynos close to that? Or maybe its just the rx8 pcm control module. is it finicky? I really dont know whats going on, but i do know that this car does not have 238HP crank. it would be dynoing at over 200 to the wheels if it did. Whats the highest anyones dynoed 170HP to the wheels? ::rollseyes::

But again, i knew this when i bought the car, and didnt buy it for a drag light to light car. Its just a little dissapointing to have someone say "whats the HP on that awesome looking car and how much was it?" To which my response is "Well it 'has' 238HP, but in actuality it has closer to 200HP, and it cost about 30K". That IS a lot of money for simple a stylish good handling car. This car really does need a 30HP boost, either in turbo form or supercharger form, or PCM tuning etc. For 30K it should be able to compete more evenly with the market it was suppose to compete with, i.e. z, g35 etc.. And before anyone says "well it out handles those cars".. yes, yes it does, but those cars will smoke us 9/10. And they handle close to the level our cars do., So the top end power wont help much when they walk away fromt he line and keep walking, even thru turns.

I do love my car though, just wish mazda thought things out better.

PoorCollegeKid

From what I've read on this forum, the RX8's emissions problems were not caused by the engine itself but rather by a catalytic converter that did not last the 120k miles mandated by federal law and did not heat up quickly enough to pass cold start emissions testing with the fuel maps that gave the Renesis its original 247hp rating. In order to meet these requirements, the ECU had to be reprogrammed, resulting in a significant loss of power. It wouldn't surprise me to see a new catalytic converter coupled with a more powerful Renesis when the RX8 is updated in the near future, but this all depends on how quickly Mazda can find a reliable high temperature catalystand incorporate it in to its engine design.

reddragonmd

So would getting a high flow cat, and some piggy backed ECU upgrade give this car back its umph? Its just frustrating, thats all. :o

Lufa

Woo hoo another HP thread....

reddragonmd

If your not the least bit urked by it, then go you. A 50-60HP difference from claimed crank HP to WHP is retarded. I was only asking for the rationale behind it. Which i now have.

93rdcurrent

Uh yes there is. I went from an E 36 M3 with 289 hp stock and I had a Dinan chip upgrade with exhaust. I have also built other cars up above the 500 hp range. My wife's E 46 325 xi has 185 hp and my RX-8 is certainly between the M3 and 325. I would venture to guess that I am seeing around 200-205 hp at the wheels. So I don't know why you think they can't achieve it.

Lufa

It's not that im not irked... 9 months ago when I started the 50th one of these exact threads I was irked, now I am fine with 220 crank HP car. Yeah you can tune it back to 238-249, but as far as I can tell most RX8's are putting around 220 to the crank and 170-180 to the wheels.

My opinon, backed by a ton of research on this board staring at a billion dyno's of stock engines, gtech's, trap times etc.

Yes, there are some statistical outlyer, and modders who do a whole lot better than 220.

reddragonmd

You venture to guess? Because we all know how well that works in gauging a cars power output. Get it on a dyno and im sure your only seeing 170-180HP to the wheels. There is no way your 8 is putting down 205/wheels.

Frank Patrick

Several members have done the dyno- your right at 170-180
In fact a members car recently tested last week -gave three readings- 177, 170 181-The dyno was good, either these cars don't test well or something (computer related?) might be going on. either waythere does seem to be 200 ponies running

93rdcurrent

I never said my butt dyno was perfect but I do know that other cars out there in the 200+ hp range that I have raced against (and yes I do that from time to time) have lost. My wife's 325 xi (185 hp stock) doesn't stand a chance either from how I feel when driving it. Maybe it has something to do with the fact that I don't shift into second until about 32 mph and 3rd until 62 mph. But I have a history of driving high hp cars fast and I am fairly good at judging the feel of a car. And yes it is faster by quite a bit then our Audi A4 1.8t quattro sport (190 hp rating stock) too which was AWD just like the Beemer is. I know that part of it is driver ability but I was the driver in all of the cars. I also built up my '91 Toyota MR2 from 190 hp stock to 575 hp at the crank in a 3 year period. So I have experienced the feel of a car that goes through several hp changes. I am no dyno though.

One problem I have with dyno testing on the 8 is that you need to take into consideration the normal driving that the car has been subjected to. If I drive the car like a granny for a week and then jump on the dyno there may be a computer problem getting it to full hp potential. Our PCM or ECU is supposed to change depending on driver input over a period of time. The idea was that if your normal driving style was the typical grocery go getter then the car would tune itself for that driving style. But if you are like me and you drive the car like you stole it then it would tune itself for a sportier reaction to the pedal. Could this be the factor giving 170-180 hp readings? Was the LSD causing problems? It's hard to say for sure but I know that Maurice complained about the Limp Mode when he was putting his car on the dyno.

Frank Patrick

You know-I was not smart in this area of Dynos- but the young lady who actually set the test up told me almost eactly-what you just said-- I never knew the you are actually programing, when you drive as the computer is learning your driving style. She also, said that iwill respond to more aggressive driving stlye in kind

93rdcurrent

After my MR2 was on the dyno a few times I thought I understood dyno testing pretty well. That was until my introduction to this car. It seems that dyno testing technology needs to catch up to the rest of the automotive technology. There should be a mode we can select by doing a little dance with some of the controls or by plugging in a relay that would set the car to optimum performance settings on the PCM and would disengage the DSC/TC and unlock the LSD. Then we could be certain we were getting a good run on the dynos. Mazda needs to help us out here or tell us how they achieved the dyno runs.

Berni

I don't know how much, however it IS fun to drive and when i Autocross i beat a 390 HP mustang cobra and i am no mario..... aside from that I don't care what the Number is or is not. but i would not turn down any compensation the mazda would offer if a problem is discovered.

mobilezen

...mario :D I thought for a sec you meant super mario but then I caught on...andretti right? I would like to be known as an Alex (Zanardi) LOL but I am in another galaxy compared to his driving skills...I think he said he's trying to make it back on the circuit. Read an article awhile back.

Back on the subject, about 93rdcurrent's comment. It's interesting I have met many people that can definitely "feel" the amount of hp of a car. One of my friends guessing 250hp at the wheels with his civic on the dyno, came out to 243hp. Another friend tuned his MR2 to 350 to the ground, came out to 368. So yes, there are people that can feel hp and I believe it. Now I didn't mean to start an arguement in here and it is very hard to discount someone else's own experiences. Pics always help and also dyno sheets, readouts, etc.

r0tor

iTrader: (1)

anyone getting 170-180hp at the wheels isn't dynoing there car right... using real world driving tests i'm putting around 196 to the wheels

shelleys_man_06

How can you confirm that?

nosubstitutec4s

there should be no difference in the power produced by the engine. from what i know, the engines are hand assembled, but all the parts are made by machines that do the same thing every day, time and time again.