hope this helps

sorry wrong file

lol

That's the best explanation I've seen yet! :D

hope this helpsIt helps explain where fruit salad comes from.... not sure about the dyno.

It helps explain where fruit salad comes from.... not sure about the dyno.

I think those are cousins to IkeWRX's humpin' bananas

hope this helps
http://www.rx8club.com/attachment.php?attachmentid=35322&stc=1

Best. explaination. ever.

file is either too big to open or i dont know what the hell i'm doing.i vote for i dont know what the hell i'm doing.but i found it on mazdamp3 site.

man this thread makes me laugh. :D

Statement:


There is no true way to generate flywheel horsepower from a chassis dynamometer because of frictional losses in the driveline, clutch, transmission, differential and tires. Also, variations in testing procedures will cause highly disparate readings: open/closed hood, high/low humidity, high/low ambient temperature, tire pressure, how tightly the car is tied down, which gear the car is tested in, etc.

In addition, we have determined that, in order to prevent damage to the catalytic converter and the entire driveline, when the PCM determines unusual operating parameters such as excessive slip in the drivetrain from the front to the rear wheels, it causes a rich high-RPM mixture and retardation of the timing. All these items combine to cause apparent considerable horsepower loss.

BACKGROUND:

Horsepower Measurement

There is only one true method for measuring engine horsepower: on an engine dynamometer at constant speed and utilizing variable load.

The engine should use the same intake and exhaust system as in the car. HP results must be corrected to SAE J1349 standards as listed below:

77 degrees Fahrenheit
Sea level
0% humidity
Correction factors must be applied to reference the measurements to SAE J1349 standards. Any correction factor beyond 7% is considered invalid.

Chassis Dynamometers

SAE has produced a technical paper (SAE Technical Paper Series 2002-01-0887) that attempts to address the ongoing debate about inertia dyno horsepower versus OEM net horsepower. You can order a copy by visiting their website at www.sae.org -- we have no intentions of getting mired in the middle of this discussion.

Bottom line: If used properly, chassis dynos are great tools to assist with tuning and modifying vehicles. It is impossible to measure the actual flywheel horsepower because there are simply too many variables.

Other issues that are unique to the RX-8:

The RX-8 uses a very advanced engine management system. Besides precisely controlling the operating parameters of the engine, self-preservation (of both the engine and the catalytic converter) is also considered.

The engine management system continuously monitors all engine functions and adjusts accordingly. For example:

Under heavy load acceleration, the timing is retarded and the fuel mixture richened to reduce the likelihood of pre-ignition or spark knock. If spark knock is encountered, a knock sensor senses the condition and further retards the timing. Gradually timing is advanced and fuel mixture leaned after the load is reduced.

A second reason for fuel enrichment is that when timing is retarded, exhaust temperatures increase; a richer mixture lowers the exhaust temperatures and reduces the chances of damaging the catalytic converter.

In real world driving, this all goes unnoticed to the driver and appears seamless with no disruptions to the performance of the engine. The car encounters a load under acceleration but the load quickly diminishes as the car accelerates in each gear.

Operating on a chassis dynamometer, however, creates a completely different environment. Inertia dynos use a known mass that is accelerated to measure torque at the wheels. This is usually done in one gear under heavy load conditions:

Only the rear wheels are turning while the front tires remain stationary.

On cars equipped with DSC with traction control, the difference in speed between the front and rear wheels is sensed and the power is reduced immediately to compensate for what the car senses as excess wheel spin.

If the DSC is turned off, the traction control is disabled but the brake functions of the DSC are still operational.

If the DSC system is completely disabled, this removes the brake functions from the equation, however it does not fully remove the engine management system functions.

The ABS hydraulic unit/control module (HU/CM), or the DSC HU/CM for cars with DSC, determines vehicle speed by comparing the speed of all four wheels. If two are turning and two are stationary, it will still compute a speed but senses that the car is experiencing excessive wheel spin. To protect against engine or catalyst damage:

The engine management system compares the throttle opening, gear selection (determined by engine speed and road speed) charging efficiency and engine coolant temperature to determine the driving condition.

Since the car is under heavy load, in a tall gear (testing is usually performed in third or fourth gear), with a wide throttle position angle (wide open), spark timing is reduced and the fuel mixture is richened to reduce the occurrence of spark knock and to reduce catalytic converter temperatures.



This came from rotarynews.com

Cliffsnotes: The car when being dyno'ed senses that the front wheels are not turning and essentially goes into "safe mode." Even with DSC and TCS turned off it will still sense abnormal engine use, and possible abuse and changes fuel maps and timing to reduce wear on the powertrain and emmisions control systems.

This same problem is also being experienced by BMW M3 and Porsche C4 owners.

thanks ICEMAN i could not figure out how to do that.

Yes!!!

IcemanVKO is right on the money.

This is exactly what is happening!
I have read the OBDII spec and Mazda service manuals and came to the same conclusion.
This is also the reason why after market mods are going to be hard to get right.

Iceman

Finally an in depth explanation on what is happening to the X during a dyno. Thanks much for the info. All 238 hp non-beleivers are now proven wrong. Future cars will make dynos inaccurate and obsolete. Too bad for those who spent their money to have it done on their 8. It won't work plain and simple.

Hp issue is over. I got my 238hp. This confirms what I could already feel at the the accelerator pedal.

Iceman

Finally an in depth explanation on what is happening to the X during a dyno. Thanks much for the info. All 238 hp non-beleivers are now proven wrong. Future cars will make dynos inaccurate and obsolete. Too bad for those who spent their money to have it done on their 8. It won't work plain and simple.

Hp issue is over. I got my 238hp. This confirms what I could already feel at the the accelerator pedal.


Holy crap - there wasn't any proof of ANYTHING. It was a well-written piece saying "We just don't know".

:)

Has anyone run on an AWD dyno??? I have one a few towns over.... All 4 wheels spinning... under load....

--kC

Has anyone run on an AWD dyno??? I have one a few towns over.... All 4 wheels spinning... under load....

--kC


How would the front wheels spin?

A 4 wheel Dino, would have to have some sort of track, or belt that the car would move and thus pull the tires with it. The problem with this system, is that a lighter front tire would increase your HP output.

Or they could have a roller for the front wheels, that turned at the same speed as the rear. I doubt they make a dyno that turns the front tires at the same speed as the back.

A 4wd Dyno would likely expect the front tires to pull, which these do not.

eh, he beat me to it. whatever... :p

Statement:


There is no true way to generate flywheel horsepower from a chassis dynamometer because of frictional losses in the driveline, clutch, transmission, differential and tires. Also, variations in testing procedures will cause highly disparate readings: open/closed hood, high/low humidity, high/low ambient temperature, tire pressure, how tightly the car is tied down, which gear the car is tested in, etc.

In addition, we have determined that, in order to prevent damage to the catalytic converter and the entire driveline, when the PCM determines unusual operating parameters such as excessive slip in the drivetrain from the front to the rear wheels, it causes a rich high-RPM mixture and retardation of the timing. All these items combine to cause apparent considerable horsepower loss.

BACKGROUND:

Horsepower Measurement

There is only one true method for measuring engine horsepower: on an engine dynamometer at constant speed and utilizing variable load.

The engine should use the same intake and exhaust system as in the car. HP results must be corrected to SAE J1349 standards as listed below:

77 degrees Fahrenheit
Sea level
0% humidity
Correction factors must be applied to reference the measurements to SAE J1349 standards. Any correction factor beyond 7% is considered invalid.

Chassis Dynamometers

SAE has produced a technical paper (SAE Technical Paper Series 2002-01-0887) that attempts to address the ongoing debate about inertia dyno horsepower versus OEM net horsepower. You can order a copy by visiting their website at www.sae.org -- we have no intentions of getting mired in the middle of this discussion.

Bottom line: If used properly, chassis dynos are great tools to assist with tuning and modifying vehicles. It is impossible to measure the actual flywheel horsepower because there are simply too many variables.

Other issues that are unique to the RX-8:

The RX-8 uses a very advanced engine management system. Besides precisely controlling the operating parameters of the engine, self-preservation (of both the engine and the catalytic converter) is also considered.

The engine management system continuously monitors all engine functions and adjusts accordingly. For example:

Under heavy load acceleration, the timing is retarded and the fuel mixture richened to reduce the likelihood of pre-ignition or spark knock. If spark knock is encountered, a knock sensor senses the condition and further retards the timing. Gradually timing is advanced and fuel mixture leaned after the load is reduced.

A second reason for fuel enrichment is that when timing is retarded, exhaust temperatures increase; a richer mixture lowers the exhaust temperatures and reduces the chances of damaging the catalytic converter.

In real world driving, this all goes unnoticed to the driver and appears seamless with no disruptions to the performance of the engine. The car encounters a load under acceleration but the load quickly diminishes as the car accelerates in each gear.

Operating on a chassis dynamometer, however, creates a completely different environment. Inertia dynos use a known mass that is accelerated to measure torque at the wheels. This is usually done in one gear under heavy load conditions:

Only the rear wheels are turning while the front tires remain stationary.

On cars equipped with DSC with traction control, the difference in speed between the front and rear wheels is sensed and the power is reduced immediately to compensate for what the car senses as excess wheel spin.

If the DSC is turned off, the traction control is disabled but the brake functions of the DSC are still operational.

If the DSC system is completely disabled, this removes the brake functions from the equation, however it does not fully remove the engine management system functions.

The ABS hydraulic unit/control module (HU/CM), or the DSC HU/CM for cars with DSC, determines vehicle speed by comparing the speed of all four wheels. If two are turning and two are stationary, it will still compute a speed but senses that the car is experiencing excessive wheel spin. To protect against engine or catalyst damage:

The engine management system compares the throttle opening, gear selection (determined by engine speed and road speed) charging efficiency and engine coolant temperature to determine the driving condition.

Since the car is under heavy load, in a tall gear (testing is usually performed in third or fourth gear), with a wide throttle position angle (wide open), spark timing is reduced and the fuel mixture is richened to reduce the occurrence of spark knock and to reduce catalytic converter temperatures.



This came from rotarynews.com

Cliffsnotes: The car when being dyno'ed senses that the front wheels are not turning and essentially goes into "safe mode." Even with DSC and TCS turned off it will still sense abnormal engine use, and possible abuse and changes fuel maps and timing to reduce wear on the powertrain and emmisions control systems.

This same problem is also being experienced by BMW M3 and Porsche C4 owners.

Yes, yes, all this makes sense. But when you compare it to real world G-tech like machines and 1/4 mile runs (good and bad) you still get too much of a disparagee. While I agree there are quite a few factors that might alter an dyno reading my question is this. When you go to many other boards you will not see the huge differences like we have. Furhtermore if all these dyno readings were so "off the mark" due to any number of variables how can all the dynos you do see for other cars coobrating (<sp?) their HP be OK and ours wrong. I like my car, but there is know way it makes 238 HP at the crank. Granted its torque that moves you, and in the end its the gearing thats the final piece of the puzzle that will affect acceleration, but even if you concider the fact that off the line performance is less than stellar, after you wind the engine up to 9K its elementary. If the car has balls up high once you get up there keeping it there is easy, therefore you would accelerate alot faster. 1/4 miles times and G-techs tell a whole other story that what they say are crank HP is. Ive heard on this board that our tranny (manual) is based on the Miata. If drivetrain loss is an issue lets look at a Miatas. Better yet, lets find a shop that dyno'd a Miata and '8 on the same day and see just how much a difference there really is (I realize there may be some gearing issues here - but dont they test at 1:1 gearing for HP). I personally dont think that tire type and some other minor issues will vary the results that the post mentions significantly. I personally think that is Mazda BS'n its way out. Yes these things make a difference but come on, if that was sooooo true, how can guys with other car types go to the same Dyno facility at different times of the year with different operators get simalar results. Where do all the variable differences go in this circumstance. Yes they have differences but not the large numbers the Mazda Statement would leave you to believe.

the car is short on HP - period. Still LOVE it though :D :D :D

ps - oh by the way, I shot of a letter of this simlar statement of mine to Mazda when I got their Satifactin Survey - So I'll see what happens with that - my hopes are high though.

Yes, yes, all this makes sense. But when you compare it to real world G-tech like machines and 1/4 mile runs (good and bad) you still get too much of a disparagee. While I agree there are quite a few factors that might alter an dyno reading my question is this. When you go to many other boards you will not see the huge differences like we have. Furhtermore if all these dyno readings were so "off the mark" due to any number of variables how can all the dynos you do see for other cars coobrating (<sp?) their HP be OK and ours wrong. I like my car, but there is know way it makes 238 HP at the crank. Granted its torque that moves you, and in the end its the gearing thats the final piece of the puzzle that will affect acceleration, but even if you concider the fact that off the line performance is less than stellar, after you wind the engine up to 9K its elementary. If the car has balls up high once you get up there keeping it there is easy, therefore you would accelerate alot faster. 1/4 miles times and G-techs tell a whole other story that what they say are crank HP is. Ive heard on this board that our tranny (manual) is based on the Miata. If drivetrain loss is an issue lets look at a Miatas. Better yet, lets find a shop that dyno'd a Miata and '8 on the same day and see just how much a difference there really is (I realize there may be some gearing issues here - but dont they test at 1:1 gearing for HP). I personally dont think that tire type and some other minor issues will vary the results that the post mentions significantly. I personally think that is Mazda BS'n its way out. Yes these things make a difference but come on, if that was sooooo true, how can guys with other car types go to the same Dyno facility at different times of the year with different operators get simalar results. Where do all the variable differences go in this circumstance. Yes they have differences but not the large numbers the Mazda Statement would leave you to believe.

the car is short on HP - period. Still LOVE it though :D :D :D

ps - oh by the way, I shot of a letter of this simlar statement of mine to Mazda when I got their Satifactin Survey - So I'll see what happens with that - my hopes are high though.


After reading this I am left wondering if you read the whole thing?

Nut Shell is, the Computer compensates for wheel spin, and reduces power, in order to keep you from tearing up the fragile rotory engine, and the silly Cat, which is too close to its high reving hot self. So if you test it on a system designed to simulate wheel spin at high RPM, you will find that the computer will easily knock off 15-30 hp, by trying to lower the exhaust temps and stuff.

My question is where is the outcry for a computer not allowing me to tear up my car? I take issue with a computer that thinks it knows more about driving than me.

[, how can guys with other car types go to the same Dyno facility at different times of the year with different operators get simalar results. Where do all the variable differences go in this circumstance. Yes they have differences but not the large numbers the Mazda Statement would leave you to believe.

the car is short on HP - period. Still LOVE it though :D :D :D[/QUOTE]


Your missing the point. The rx8 is an ultra modern high tech vehicle. It's not like older or modern low tech cars on the road. Eventually all modern cars will not read correctly on dynos, as they catch up to the 8 in safety and engine technology. Be glad you got an ultra modern car. The 8 detunes it'self automatically when it senses abuse on engine or drivetrain. It, can't be dynoed period. Re-read the article. It goes into safe mode on a dyno. Seat of the pants dyno is subjective. I say yes way it has 238hp seat of the pants. You say no way. Everyone has their opinion.

Eventually all modern cars will not read correctly on dynos, as they catch up to the 8 in safety and engine technology. Be glad you got an ultra modern car. The 8 detunes it'self automatically when it senses abuse on engine or drivetrain. It, can't be dynoed period. Re-read the article. It goes into safe mode on a dyno. Seat of the pants dyno is subjective. I say yes way it has 238hp seat of the pants. You say no way. Everyone has their opinion.


Trap speed...there's a good indication of power for a car. :)

Even the lowly GTech would be helpful in measuring gains vs. a baseline...and from the sounds of things, that may be the best way. :(

After reading this I am left wondering if you read the whole thing?

Nut Shell is, the Computer compensates for wheel spin, and reduces power, in order to keep you from tearing up the fragile rotory engine, and the silly Cat, which is too close to its high reving hot self. So if you test it on a system designed to simulate wheel spin at high RPM, you will find that the computer will easily knock off 15-30 hp, by trying to lower the exhaust temps and stuff.

My question is where is the outcry for a computer not allowing me to tear up my car? I take issue with a computer that thinks it knows more about driving than me.

True, but do you think our cars are so unique and sooo modern and so advanced that the problem would only be with us. I dont. My point isn't JUST the computer issue - its the real world facts - thats the G-tech and 1/4 mile issues. I would compare are cars to a the lastest Honda Prelude in a way. Low on torque power high up (I dont know the weight of the car) simlar power (yes we are faster but not hugely so), similar g-tech times and 1/4 miles. I really dont care about running the quarter mile, just using it as a base line. These test take into accout real world driving experinces. All in all, you can quabble with the computer doing this or that but when put up to real world results and you extrapolate numbers they just dont add up. And if they add up for many, many, many new and old cars they should add up for us.

Results are all that matter. Horsepower numbers are irrelevant unless you just want to brag. If your car runs a certain speed now and a mod made it faster, that's all that counts. Everyone needs to get off of the whole dyno numbers crap and focus on the actual performance. The most horsepower may win on a computer screen where that is the only factor but in the real world there are too many other variables to consider to make this a true statement. If you insist on getting a dyno, do so to establish a baseline by which you judge gains in percentage over the original. The original number is irrelevant. A gain is a gain and faster is faster. There is no power to recover if there is no performance to recover. Ther performance is the proof.

[, how can guys with other car types go to the same Dyno facility at different times of the year with different operators get simalar results. Where do all the variable differences go in this circumstance. Yes they have differences but not the large numbers the Mazda Statement would leave you to believe.

the car is short on HP - period. Still LOVE it though :D :D :D


Your missing the point. The rx8 is an ultra modern high tech vehicle. It's not like older or modern low tech cars on the road. Eventually all modern cars will not read correctly on dynos, as they catch up to the 8 in safety and engine technology. Be glad you got an ultra modern car. The 8 detunes it'self automatically when it senses abuse on engine or drivetrain. It, can't be dynoed period. Re-read the article. It goes into safe mode on a dyno. Seat of the pants dyno is subjective. I say yes way it has 238hp seat of the pants. You say no way. Everyone has their opinion.[/QUOTE]

The point you're missing is that there have been some reports of safe modes and things like that, but there are ways to overcome it and there are also plenty of dyno runs where the car does not go into safe mode. The 8 hardly detunes itself in this socalled safemode and the system is not liek that of the M3 where you can actually notice on dyno graphs what the ECU is doing. If you think for a second the ECU brings the car down to 175ish WHP to save your drivetrain and engine you're crazy, that would be about 25WHP less than what it should be stock and it's not going to make a damn bit of difference in saving anything if there's a problem.

The dynos correspond to the 1/4 mile runs and trap speeds which correspond to my buttdyno, plus there being several examples of others cars to compare it to where the evidence points to the RX-8 being down on power. Lastly Racing Beat did an engine dyno and came up with less than 218hp and I believe that was with an intake. All the evidence points to the RX-8 being down on power, if you want to believe in the mystical safemode from the front wheels not spinning be my guest. Ignorance is bliss sometimes.

It can be dynoed just fine, if there was really a problem the tuner at the dyno would catch it, just like they did with the first M3s that were dynoed. There was no contraversey about the M3s being down on power because it was so apparent what was going on.

Great points, Ike...

Results are all that matter. Horsepower numbers are irrelevant unless you just want to brag. If your car runs a certain speed now and a mod made it faster, that's all that counts. Everyone needs to get off of the whole dyno numbers crap and focus on the actual performance. The most horsepower may win on a computer screen where that is the only factor but in the real world there are too many other variables to consider to make this a true statement. If you insist on getting a dyno, do so to establish a baseline by which you judge gains in percentage over the original. The original number is irrelevant. A gain is a gain and faster is faster. There is no power to recover if there is no performance to recover. Ther performance is the proof.

I agree completely, the only caveot (sp? I suck at spelling) is when it comes to did you get what you paid for issue. If I pay for 3000 squre feet of house and I was sold 2800 SF could I live with if I still like it - yes - did I over pay? Yes, is this ok to me no. But now we will be getting into now is more of a philosophical arrgument of what "worth" is - to me there are two schools of though on this board.

1. You enjoy the car reguardless of what the acutal HP is. And "yes" more HP would be great but I can live without it even though I was told it was one thing and in all actuallity it something all together. But HP is one category to describe a car and its worth, not the only.

2. You enjoy the car regurdless of what the actual HP is BUT you want what you paid for regurdless if its the manual they forgot in the glove box or the HP you were sold - if it makes your car faster or not is necesarrily relevant.

I for one am in 2. This doesn't apply just to my car but for any purchase in life. I feel people who fall in 1 are just grappling at excuses to justify not getting what they deserve. And while HP may not be the only category to describe worth, in a "sports car" its a big piece of the puzzle, no matter how good everything else is and if I was sold more HP I want it. <-----My opionion. My philosophy I adhere to.

Your missing the point. The rx8 is an ultra modern high tech vehicle. It's not like older or modern low tech cars on the road. Eventually all modern cars will not read correctly on dynos, as they catch up to the 8 in safety and engine technology. Be glad you got an ultra modern car. The 8 detunes it'self automatically when it senses abuse on engine or drivetrain. It, can't be dynoed period. Re-read the article. It goes into safe mode on a dyno. Seat of the pants dyno is subjective. I say yes way it has 238hp seat of the pants. You say no way. Everyone has their opinion.

Not a flame, but how is the RX-8 so much more high tech and modern than other cars on the road? The rotary motor has been around since 1957 and in production cars since 1968(I believe). Is the Chrysler 300C/Dodge Magnum leaps and bounds above other cars because it has a Hemi? 340 HP 390 ft-lbs tq, 4066 lbs, 17 mpg / 25 mpg, 0-60 in 5.6 sec's and active cylinder deactivation. I'd say thats more high tech than a RX-8, the car weights a 1000 punds more, gets than same gas mileage as a RX-8(or better) and is faster 0-60 and quarter mile(14.1-sec. clocking at 101.1 mph). I'll count that as modern.

I don't mean to be a stickler but the hemi wasn't invented just yesterday(1951). And that is just a modification to an engine(piston driven) that has been around for 100 years. Just because it's been around for awhile doesn't make it bad. To me that makes it good. Just my 2 cents

Info on hemi:
http://www.allpar.com/mopar/hemi/hemi.html

Well that was my point(In a twisted mumbling way), the rotary is not new or ultra modern. It has been updated over the years as most engines are. The Hemi is no where near new and had most of its big "heyday" back in the 1950's to early 1970's. Both motors are modern, yes, is either ultra modern, no. I would count ultra modern as to something we have never seen before(I'm thinking laser beams, and hyper drives. :D ).

It's not that the RX is new and modern, it is the PCM that is new and modern.
The type of control system used on the RX8 is very new and is not on many cars yet.

People you need to read the Ford OBDII specs and the Mazda service manuals then you might understand what all is going on with this system.

It is looking at every sensor and if they are not within the programmed range then something WILL CHANGE!

This system is NOT like any other PCM used on RX cars.

The rotary news article was posted before and is buried somewhere deep inside this board. As before, there are some who choose to believe it and those that will never believe the car has 238hp. I don't think the HP debate will ever end, but in my mind most reputable sources seem to indicate the power is not all that off the mark. According the performance test results from the car mags, 238 hp seems about right. R&T, C&D, and MT all got 0-60 in 5.9-6.1 secs and 1/4 mi. of ~14.5 secs. The car has consistently performed when driven by the pros.

All I can say is the power "feels" right to me. I came from an E36 M3 which had similar performance specs according to the car mags, and my RX-8 feels just as fast and is even more fun to drive. I used to own an FD RX-7 which did feel faster, but mostly due to the turbo rush. Currently also own a 540 BMW which has the torque grunt advantage, but really doesn't feel any faster and is far less nimble. Never dynoed the M3 or any of my cars, will never dyno the RX-8 because there's nothing to prove - I'm happy with it.

At the end of the day, the car feels right, it performs, and makes me smile every time I drive. :)

I really hate how people say they don't feel or do feel that the car has 238 HP....fact of the matter is, 240-ish HP feels very differently from car to car, mainly due to the difference in weights and more importantly, the TORQUE CURVE.

IMHO the car feels like it has 238 HP for sure, but it also feels like it only has 155-ish torque...in other words, without a good torque curve, 238 HP means nothing. Not that the RX-8 has a terrible curve, just not as good as other cars, and that's the nature of the rotary. That's why you have a 9K RPM redline. Get used to it, and row that gear box.

What alot of people don't realize is that cars that usually have 240-ish HP, by nature of design, usually have a larger amount of torque making them FEEL powerful. So in short, when someone says they can "feel that the HP is there, or isn't there" they are actually talking out of their ass. LITERALLY.

The way it performs is all that matters. It performs as advertised. You can't compare this to square footage in a house that you are buying or anything else. It doesn't work that way. If the car performs as advertised, it must have the same amount of power that it did at the time the original ratings were published.

Would you guys be happier if the car made 250 hp but had less average power and was the same speed or slower? Numbers are all that matters right? :rolleyes:

If you want a faster car, buy a faster car. I've never had an issue with the car's HP. Sure, I'd like more low end torque, but the the car as a whole is fantastic. I also don't see the need to mod out cars. All you do is spend more money and make the car less reliable, potentially void the warranty, and lower resale value. If you want a faster car, buy a faster car. I've alway said, if you want to street race, get a V8 or similar vehicle with low end torque. Easier car to launch, and much less abuse when you can launch at 2500 rpms.

The dynos correspond to the 1/4 mile runs and trap speeds which correspond to my buttdyno, plus there being several examples of others cars to compare it to where the evidence points to the RX-8 being down on power. Lastly Racing Beat did an engine dyno and came up with less than 218hp and I believe that was with an intake. All the evidence points to the RX-8 being down on power, if you want to believe in the mystical safemode from the front wheels not spinning be my guest. Ignorance is bliss sometimes.

It can be dynoed just fine, if there was really a problem the tuner at the dyno would catch it, just like they did with the first M3s that were dynoed. There was no contraversey about the M3s being down on power because it was so apparent what was going on.


The rx8 system is so new you could not possibly be the expert you pretend to be. Re- read the article. There is a safe mode. How would you know the limitations of safe mode on an 8? How would you possibly know what the car is engineered to do while sensing unusual circumstances?

I had a 85 transam 195 hp and a 86 z28 Iroc 220 hp. The rx8 would kill both these cars up to 0-110 mph. the 8 cannot be dynoed accurately. It defeats the dyno . If you don't like the article, and do not beleive it, fine. I think it's a much more reliable source than you are. Thanks for your BS anyway.

Am I still allowed to like my car?

The rx8 system is so new you could not possibly be the expert you pretend to be. Re- read the article. There is a safe mode. How would you know the limitations of safe mode on an 8? How would you possibly know what the car is engineered to do while sensing unusual circumstances?

I had a 85 transam 195 hp and a 86 z28 Iroc 220 hp. The rx8 would kill both these cars up to 0-110 mph. the 8 cannot be dynoed accurately. It defeats the dyno . If you don't like the article, and do not beleive it, fine. I think it's a much more reliable source than you are. Thanks for your BS anyway.


If an Engine is drastically pulling timing, it shows up on a dyno plot. I believe that's the point he's trying to make, and a point I happen to agree with. People are comparing it to what the M3 does - the way people figured out what the M3 was doing is by watching it on the machine. Other than 'lower than expected numbers' there's nothing obviously going on with the RX8 to indicate a massive yank in timing, (power). Just dyno's which show Mazda's current 238hp figure to be about 20hp too optimistic. Taking the weight of the vehicle, the gearing, and the wheel HP, most people have trap speeds in the 1/4 mile which correspond to the dyno-measured power. If people were trapping at 100mph with 175whp, there'd be a stronger case for "The RX8 HAS the power, but doesn't show the power on the dyno due to massive software adjustments".

If an Engine is drastically pulling timing, it shows up on a dyno plot. I believe that's the point he's trying to make, and a point I happen to agree with. People are comparing it to what the M3 does - the way people figured out what the M3 was doing is by watching it on the machine. Other than 'lower than expected numbers' there's nothing obviously going on with the RX8 to indicate a massive yank in timing, (power). Just dyno's which show Mazda's current 238hp figure to be about 20hp too optimistic. Taking the weight of the vehicle, the gearing, and the wheel HP, most people have trap speeds in the 1/4 mile which correspond to the dyno-measured power. If people were trapping at 100mph with 175whp, there'd be a stronger case for "The RX8 HAS the power, but doesn't show the power on the dyno due to massive software adjustments".


Thanks for the explanation. Still this does not explain the the posted article as to what happens to the 8 while on the dyno. Sounds like it adds fuel to preserve the catalytic converter. What else does the pcm on this car do when sensing a dyno run. who knows? Are you saying The 8 dynoes the same as any car? Mazda says it does not. I admit the engine dyno of 218hp does put the hp figures under suspect.

Thanks for the explanation. Still this does not explain the the posted article as to what happens to the 8 while on the dyno. Sounds like it adds fuel to preserve the catalytic converter. What else does the pcm on this car do when sensing a dyno run. who knows? Are you saying The 8 dynoes the same as any car? Mazda says it does not. I admit the engine dyno of 218hp does put the hp figures under suspect.


I'm saying nobody really knows. If there was a way to monitor the Stock ECU during a dyno, perhaps we'd all know for sure. Based on a preponderance of the evidence, I'm inclined to vote for "Mazda's revised Crank HP numbers need revision"

:)

Again - it's just a number. The RX8 is a pretty fun car. :) Most people would rather Mazda simply came clean, ya know?

Again - it's just a number. The RX8 is a pretty fun car. :) Most people would rather Mazda simply came clean, ya know?


I gotta agree with the fun part. Whatever the hp the 8 is beutifully ballanced handleing and powerwise. It easily fullfills it's purpose to please the enthusiast.

The way it performs is all that matters. It performs as advertised. You can't compare this to square footage in a house that you are buying or anything else. It doesn't work that way. If the car performs as advertised, it must have the same amount of power that it did at the time the original ratings were published.

Would you guys be happier if the car made 250 hp but had less average power and was the same speed or slower? Numbers are all that matters right? :rolleyes:

Actually its exactly like a house - you :rolleyes: at numbers on one hand but say if it performs as advertised (which is based on numbers!) thats all that matters. Pick one.

Lets go with the "performs as advertised". If i told you the house had 2 bedroom 2 baths with a heat pump system that kept the house energy bills overall lower, double insulated window systems that lowered your energy bills and had 3000 SF and the sales person or add said the house was in a great neighborhood with high quality of life factor and you moved in and all these things were true you would not have a problem but if it turned out the house had all these amenities but only had 2800 square feet you would be pissed because you overpaid for the SF you bought. What if that extra 200 SF allowed you to have extra piece's of furniture or better seating arrangements in you living room to better suit your needs? In other words you don't appreciate what you dont have until you have it. Its easy to say "numbers dont matter" but you kidding yourself - while they are not the "end all" to a buying decscion they do have a relevance. They help quantify what you are buying and compare it to other things. You wouldn't by a house based just on subjective or precieved information. You would want to know how old the roof and A/C system is (and where is the paper work - your "numbers" if you will.)

How is this ANY differnt for a car - Its not. Yes the car performs as advertised - as advertised for a car with about 210 HP - and thats the problem. Your premise only makes sense if you look at the whole picture not one seletive area. Increase the HP to what I believe I was sold then the "as advertised" numbers would change. So your arrgument in that sense would make sense to any car no matter what they said the HP is. Under your argument if they told you it was 1000 HP you would be ok with this :rolleyes: . NO, I think not.

And as for information on Dynos presented by a Mazda statement. This is the funniest thing to me how a lot of people are grasping at these straws. Most of us will all say that a car sales persons are one step above theives and would lie to their mother to sell a car. Just look at all the stories on this board if you need any proof. Thats why nobody just dives in and accpts the price a salesmen starts with because we know their not telling us what they'll really sell the car for. But you really dont think that person from Mazda is ANY differnt if not worse than a cars sales person. If so I have some ocean side property in Arizona I'd like to sell you. If they come clean they're are some serious $$$$ ramifications to deal with. They can lie because none of us can put up the $$$$ to prove them otherwise.

And for all those who yell about if one wants a faster car "go buy it" well you all just missed the point - wide of the mark too.

I say all of this and I LOVE driving my car - but im just not going to buy off some "Mazda Statement". Most that stuff applies to most cars anyway. And if you think our ECU's are so damn special get real - BMW's, MB's etc. all have the best of the day programing that have to do all the same things our car have to do, they may just go through it in a different way.

My Prelude had 190 hp, and Dynod at 152. The RX8 has 238 hp and Dynos at 180-190.

Looks about right to me.

Actually its exactly like a house - you :rolleyes: at numbers on one hand but say if it performs as advertised (which is based on numbers!) thats all that matters. Pick one.

Lets go with the "performs as advertised". If i told you the house had 2 bedroom 2 baths with a heat pump system that kept the house energy bills overall lower, double insulated window systems that lowered your energy bills and had 3000 SF and the sales person or add said the house was in a great neighborhood with high quality of life factor and you moved in and all these things were true you would not have a problem but if it turned out the house had all these amenities but only had 2800 square feet you would be pissed because you overpaid for the SF you bought. What if that extra 200 SF allowed you to have extra piece's of furniture or better seating arrangements in you living room to better suit your needs? In other words you don't appreciate what you dont have until you have it. Its easy to say "numbers dont matter" but you kidding yourself - while they are not the "end all" to a buying decscion they do have a relevance. They help quantify what you are buying and compare it to other things. You wouldn't by a house based just on subjective or precieved information. You would want to know how old the roof and A/C system is (and where is the paper work - your "numbers" if you will.)

How is this ANY differnt for a car - Its not. Yes the car performs as advertised - as advertised for a car with about 210 HP - and thats the problem. Your premise only makes sense if you look at the whole picture not one seletive area. Increase the HP to what I believe I was sold then the "as advertised" numbers would change. So your arrgument in that sense would make sense to any car no matter what they said the HP is. Under your argument if they told you it was 1000 HP you would be ok with this :rolleyes: . NO, I think not.

And as for information on Dynos presented by a Mazda statement. This is the funniest thing to me how a lot of people are grasping at these straws. Most of us will all say that a car sales persons are one step above theives and would lie to their mother to sell a car. Just look at all the stories on this board if you need any proof. Thats why nobody just dives in and accpts the price a salesmen starts with because we know their not telling us what they'll really sell the car for. But you really dont think that person from Mazda is ANY differnt if not worse than a cars sales person. If so I have some ocean side property in Arizona I'd like to sell you. If they come clean they're are some serious $$$$ ramifications to deal with. They can lie because none of us can put up the $$$$ to prove them otherwise.

And for all those who yell about if one wants a faster car "go buy it" well you all just missed the point - wide of the mark too.

I say all of this and I LOVE driving my car - but im just not going to buy off some "Mazda Statement". Most that stuff applies to most cars anyway. And if you think our ECU's are so damn special get real - BMW's, MB's etc. all have the best of the day programing that have to do all the same things our car have to do, they may just go through it in a different way.

Thats alot of attitude there. Your saying you distrust Mazda and do not believe the report. Other than that you have no real arguement or anything to disprove the report. Noone at Mazda is going to come clean on this item if the report is true and Mazda knows it. You can only guess with your own suspicions. You have no facts. You cannot prove or disprove what Mazda claims with dyno readings. Hold tight ,maybe more prove will come in the future to put these issues to rest.

Thats alot of attitude there. Your saying you distrust Mazda and do not believe the report. Other than that you have no real arguement or anything to disprove the report. Noone at Mazda is going to come clean on this item if the report is true and Mazda knows it. You can only guess with your own suspicions. You have no facts. You cannot prove or disprove what Mazda claims with dyno readings. Hold tight ,maybe more prove will come in the future to put these issues to rest.

Well putting out an attitude isn't my objective here. Your right I can't prove it, but im not just going to blindly believe. In my previous posts on this thread my point is if you go buy what people are geting with g-tech devices and 1/4 miles times, while these arn't professional drivers, if you get enough data from all the different timeslips and testimonials most of what I've seen or read add up to a car of 210 HP max (on average). Thats more imperical than any "letter" of explanation to me or any other rationalization. But as for believing Mazda - their track record of being at best not up front with HP speaks for itself. Weather this is miscommunicatin on a corrporate level, bad testing procedures or whatever - the facts are still there. So when you say I have my suspicions your right - but I have good reason for them.

Furthermore my main thrust of my arugument has little to do with "trusting" Mazda at all - thats just a side note to my argument. I give no real weight to it just because it cant be proven or disproven. Take that part of my argument out the rest still stands as far as I am concernd. G-techs (assuming they are set up correctly - I can see argument with that) arn't that far off from the truth and they do tell real world experiences under real world conditions. No, my main thrust of my argument has to do with getting what I paid for. And while strait line acceleration isn't the whole world to me, I don't like getting dooped. Reread all my previous posts in this thread, I'm only interested in finding out if they're lying us to avoid big costs to them bascially - and so far all ive seen with the imperical evdience is "yes".

Yes we could all agree and say for instance "yes" its only 210 HP and we would all enjoy are cars - and cant tell you how many times I've typed that line - but its not about that its - reread my post on this thread earlier about the philosophies of this argument and you'll get what I'm after.

Here's another thought. Maybe Mazda put out the report knowing it cannot be disproven. Thereby defeating the most valuable test for RWH.

Here's another thought. Maybe Mazda put out the report knowing it cannot be disproven. Thereby defeating the most valuable test for RWH.


Sounds like a good conspiracy theory to me!!!! ;) :D

Results are all that matter. Horsepower numbers are irrelevant unless you just want to brag. If your car runs a certain speed now and a mod made it faster, that's all that counts. Everyone needs to get off of the whole dyno numbers crap and focus on the actual performance. The most horsepower may win on a computer screen where that is the only factor but in the real world there are too many other variables to consider to make this a true statement. If you insist on getting a dyno, do so to establish a baseline by which you judge gains in percentage over the original. The original number is irrelevant. A gain is a gain and faster is faster. There is no power to recover if there is no performance to recover. Ther performance is the proof.

After spending the past 2 days reading up on this topic and getting friendly with the search button, this is the best thing I've read.

I really hate how people say they don't feel or do feel that the car has 238 HP....fact of the matter is, 240-ish HP feels very differently from car to car, mainly due to the difference in weights and more importantly, the TORQUE CURVE.

IMHO the car feels like it has 238 HP for sure, but it also feels like it only has 155-ish torque...in other words, without a good torque curve, 238 HP means nothing. Not that the RX-8 has a terrible curve, just not as good as other cars, and that's the nature of the rotary. That's why you have a 9K RPM redline. Get used to it, and row that gear box.

What alot of people don't realize is that cars that usually have 240-ish HP, by nature of design, usually have a larger amount of torque making them FEEL powerful. So in short, when someone says they can "feel that the HP is there, or isn't there" they are actually talking out of their ass. LITERALLY.

very good post wanted to make sure everyone reads that again

several people argue about gtech numbers showing the 8 is not making 238 but the people that make those statements never show the g-tech numbers they are talking about.

First I must say that what Mazda is claiming seems to be correct to me. All anyone needs to do to prove these claim is to hook up a scan tool to an RX-8 while it is on the dyno during a pull and then to the same car during a run through that gear on the road. Just compare the throttle position, timing, and injector pulse width readings. If there are obvious differences in even one of the numbers, then there will be a major difference in HP.

238 is bullshit. After all is said and done Maurice at Canzoomer says he feels that the number is light. And if Maurice says it's so.. It's so.

Vince

Most of the relatively stock 6 port dynos that I've seen look similar to this

http://www.rx8club.com/attachment.php?attachmentid=30989

now ignoring the max power number, and looking at the general slope of the horsepower curve. If the curve didn't freak out after 7500rpm, and followed the same slope, it looks to me like the car would put down about 210hp to the wheels. Almost every stock 6 port dyno has this erratic behavior at the top of the curve. What's the deal? Not enough air? Timing? Something else?

I dunno but sometimes I feel like I can feel that erratic power curve at around 7500 RPM...it's like it drops off or something...

Most of the relatively stock 6 port dynos that I've seen look similar to this

http://www.rx8club.com/attachment.php?attachmentid=30989

now ignoring the max power number, and looking at the general slope of the horsepower curve. If the curve didn't freak out after 7500rpm, and followed the same slope, it looks to me like the car would put down about 210hp to the wheels. Almost every stock 6 port dyno has this erratic behavior at the top of the curve. What's the deal? Not enough air? Timing? Something else?


Judging from my CanScans, I'd bet that's the result of the ECU dumping ALL KINDS of fuel into the mix. We're talking 11.x: 1 A/F ratios.

I think someone needs to try converting the throttle to being mechanically controlled, and use a stand-alone ECU (or, can you get a standalone to work with and electronically controlled throttle?). Then the engine will be forced to do whatever the tuner tells it to do. :)

Judging from my CanScans, I'd bet that's the result of the ECU dumping ALL KINDS of fuel into the mix. We're talking 11.x: 1 A/F ratios.

so then we have to explain why MazdaManiac doesnt see the pcm try to do this when he is looking thru his emanage....

I really hate how people say they don't feel or do feel that the car has 238 HP....fact of the matter is, 240-ish HP feels very differently from car to car, mainly due to the difference in weights and more importantly, the TORQUE CURVE.

IMHO the car feels like it has 238 HP for sure, but it also feels like it only has 155-ish torque...in other words, without a good torque curve, 238 HP means nothing. Not that the RX-8 has a terrible curve, just not as good as other cars, and that's the nature of the rotary. That's why you have a 9K RPM redline. Get used to it, and row that gear box.

What alot of people don't realize is that cars that usually have 240-ish HP, by nature of design, usually have a larger amount of torque making them FEEL powerful. So in short, when someone says they can "feel that the HP is there, or isn't there" they are actually talking out of their ass. LITERALLY.Sure this is true, but how the car "feels" to me is the only thing I care about.

The way a car steers, corners, handles, rides and accelerates is all about the "feeling" your senses get when you drive a car. And for me, that's where the pleasure and excitement comes from. Not some dyno run that may or may not be a good data point.

But anyway, I do have a gtech as well. I rarely use it and mainly just to benchmark how my personal cars fair vs. what the magazines get for 0-60 runs. I haven't used it on my RX-8 until last weekend, because I've always felt the power in my RX-8 was strong. Well for grins, I tried a few 0-60 runs: 7.4, 7.3, 6.8, and then 6.4 secs (with a 5k rpm clutch drop). I'm satisified. I feel if I did a 7K drop with a good launch, I'd come close to the 5.9 secs that the mags got.

Anyone can say what they want, but I love the way this car "feels" when I drive it! The car the mags have all validated its performance and my little gtech has validated my own car for me. I'm happy, all is right with the world. :)

Sure this is true, but how the car "feels" to me is the only thing I care about.

The way a car steers, corners, handles, rides and accelerates is all about the "feeling" your senses get when you drive a car. And for me, that's where the pleasure and excitement comes from. Not some dyno run that may or may not be a good data point.

But anyway, I do have a gtech as well. I rarely use it and mainly just to benchmark how my personal cars fair vs. what the magazines get for 0-60 runs. I haven't used it on my RX-8 until last weekend, because I've always felt the power in my RX-8 was strong. Well for grins, I tried a few 0-60 runs: 7.4, 7.3, 6.8, and then 6.4 secs (with a 5k rpm clutch drop). I'm satisified. I feel if I did a 7K drop with a good launch, I'd come close to the 5.9 secs that the mags got.

Anyone can say what they want, but I love the way this car "feels" when I drive it! The car the mags have all validated its performance and my little gtech has validated my own car for me. I'm happy, all is right with the world. :)


The magazines actually say their best times were done with a 7000 rpm drop - I've done a few before on a nice, warm day and the car just hooks up and flies.

As for the torque curve, its a pretty flat line - much better than the S2000s - you can still get some pull in almost any gear, even if its not a high amount of torque.

Way back when this was being discussed, Canzoomer noted, through schematics and testing, that the only sensors that monitor front wheel speeds are disabled when the DSC was fully disabled, thus there is no way for the computer to know if the wheels are turning or not. So in my opinion, this cannot be the reason, and having driven a fair amount of cars in my day, I do not believe the RX8 is making much over 210hp.