does this explain the dyno problem
11-30-2004, 12:27 PM
#6
Mmmmm... Rotary Donut
Join Date: Nov 2003
Location: Lake in the Hills, IL (NW Chicago Burbs)
Posts: 2,376
Likes: 0
Received 4 Likes
on
2 Posts
Originally Posted by JasonHamilton
It helps explain where fruit salad comes from.... not sure about the dyno.
11-30-2004, 01:35 PM
#10
---===*===---
Join Date: Nov 2004
Posts: 111
Likes: 0
Received 0 Likes
on
0 Posts
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.
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.
11-30-2004, 02:00 PM
#12
Registered
Join Date: Apr 2004
Location: Long Beach, CA
Posts: 121
Likes: 0
Received 0 Likes
on
0 Posts
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.
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.
Last edited by RenKat; 11-30-2004 at 02:03 PM.
11-30-2004, 02:01 PM
#13
Registered
Join Date: Jan 2004
Location: Milwaukee Wi.
Posts: 997
Likes: 0
Received 0 Likes
on
0 Posts
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.
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.
11-30-2004, 02:06 PM
#14
RX8 and a Truk....
Originally Posted by Roaddemon
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.
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".
11-30-2004, 02:37 PM
#16
RX8 and a Truk....
Originally Posted by Imp
Has anyone run on an AWD dyno??? I have one a few towns over.... All 4 wheels spinning... under load....
--kC
--kC
How would the front wheels spin?
11-30-2004, 02:43 PM
#17
---===*===---
Join Date: Nov 2004
Posts: 111
Likes: 0
Received 0 Likes
on
0 Posts
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.
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.
11-30-2004, 02:57 PM
#19
Registered User
Join Date: Sep 2004
Location: Louisiana
Posts: 127
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by IcemanVKO
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.
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.
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.
Last edited by silver1.3; 11-30-2004 at 03:08 PM.
11-30-2004, 03:11 PM
#20
---===*===---
Join Date: Nov 2004
Posts: 111
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by silver1.3
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 ***** 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.
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.
11-30-2004, 03:16 PM
#21
Registered
Join Date: Jan 2004
Location: Milwaukee Wi.
Posts: 997
Likes: 0
Received 0 Likes
on
0 Posts
[, 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.
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.
11-30-2004, 03:22 PM
#22
RX8 and a Truk....
Originally Posted by Roaddemon
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.
11-30-2004, 03:24 PM
#23
Registered User
Join Date: Sep 2004
Location: Louisiana
Posts: 127
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by IcemanVKO
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.
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.
11-30-2004, 03:31 PM
#24
Registered
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.
11-30-2004, 03:36 PM
#25
Blue By You
Join Date: Jun 2003
Location: Milwaukee
Posts: 8,717
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by Roaddemon
[, 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
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.