Do dyno #'s lie?
Nov 6, 2007, 09:53 AM
#61
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Ok I think I got it now-
The OP wants to know do dynos lie? Yes they do sometimes. But in comparison to the same type of dynos. If you start comparing numbers from different type of dynos, then it just gets confusing. Just because a EVO puts down 330whp on a Mustang and 390whp on a Dyno Jet doesn't mean either is lying. It just means they read horsepower differently. But if you compare the same types of dyno then you can see where one is more realistic then the other. For example if you have an EVO with basic bolt ons and one Dyno Jet tells you 312whp and the other dyno jet tells you 352whp. You take your car to the drag strip and trap 110.8mph. Then it easy to see that the more accurate or realistic one is the 312whp number. Why, because so many EVOs with similiar mods and similiar power 310-320whp are trapping around the same. Now if you compare that 312whp to a Mustang that says 265whp. I do not believe either is lying, just that read differently.
The OP wants to know do dynos lie? Yes they do sometimes. But in comparison to the same type of dynos. If you start comparing numbers from different type of dynos, then it just gets confusing. Just because a EVO puts down 330whp on a Mustang and 390whp on a Dyno Jet doesn't mean either is lying. It just means they read horsepower differently. But if you compare the same types of dyno then you can see where one is more realistic then the other. For example if you have an EVO with basic bolt ons and one Dyno Jet tells you 312whp and the other dyno jet tells you 352whp. You take your car to the drag strip and trap 110.8mph. Then it easy to see that the more accurate or realistic one is the 312whp number. Why, because so many EVOs with similiar mods and similiar power 310-320whp are trapping around the same. Now if you compare that 312whp to a Mustang that says 265whp. I do not believe either is lying, just that read differently.
Nov 6, 2007, 11:32 AM
#62
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Ok I think I got it now-
The OP wants to know do dynos lie? Yes they do sometimes. But in comparison to the same type of dynos. If you start comparing numbers from different type of dynos, then it just gets confusing. Just because a EVO puts down 330whp on a Mustang and 390whp on a Dyno Jet doesn't mean either is lying. It just means they read horsepower differently. But if you compare the same types of dyno then you can see where one is more realistic then the other. For example if you have an EVO with basic bolt ons and one Dyno Jet tells you 312whp and the other dyno jet tells you 352whp. You take your car to the drag strip and trap 110.8mph. Then it easy to see that the more accurate or realistic one is the 312whp number. Why, because so many EVOs with similiar mods and similiar power 310-320whp are trapping around the same. Now if you compare that 312whp to a Mustang that says 265whp. I do not believe either is lying, just that read differently.
The OP wants to know do dynos lie? Yes they do sometimes. But in comparison to the same type of dynos. If you start comparing numbers from different type of dynos, then it just gets confusing. Just because a EVO puts down 330whp on a Mustang and 390whp on a Dyno Jet doesn't mean either is lying. It just means they read horsepower differently. But if you compare the same types of dyno then you can see where one is more realistic then the other. For example if you have an EVO with basic bolt ons and one Dyno Jet tells you 312whp and the other dyno jet tells you 352whp. You take your car to the drag strip and trap 110.8mph. Then it easy to see that the more accurate or realistic one is the 312whp number. Why, because so many EVOs with similiar mods and similiar power 310-320whp are trapping around the same. Now if you compare that 312whp to a Mustang that says 265whp. I do not believe either is lying, just that read differently.
With that said, I just would rather do my dyno tuning in a facility that has a more accurate reading that translates at the track. True the dyno is a great tuning tool, but the #'s can be subjective. The track is the real dyno.
Nov 8, 2007, 04:36 AM
#65
Do you guys really think it's that hard for dynos to make repeatable results even at different shops? I mean seriously are we lacking the technology to do that? We're not... if every DynoDynamics shop would run in Shootout Mode then I honestly believe you could trust that the same car could dyno at a different shop and get pretty much the exact same result.
Taken from: http://www.xspeed.com.au/tech_features.php?tech_id=19
I'm so tired of seeing dyno graphs with no data. I mean seriously... why is there not a ton of data at the bottom of every graph showing air intake temps, correction factors, modes of operation, etc.
Chances are, many of you from around the automotive industry have already heard of the ShootOut system when dyno tuning cars. Dyno Dynamics, the manufacturer of Australia’s leading dynamometer brand, has for many years been considered the benchmark for both accuracy and repeatability. Now, after 4 years of effort (not to mention a substantial financial investment), they have just ‘upped the stakes’ - Dyno Dynamics has developed a system that is set to become the industry standard for power comparison. The system is called ShootOut, it is being utilised by a network of accredited Dyno Dynamics equipped workshops across Australia and will soon be available to all customers worldwide.
The ShootOut mode system is not just a hardware or software upgrade – it is a standardised approach to power measurement, designed to ensure that you can take your car to any accredited workshop and get accurate power measurements for your car. The results will be the same regardless of which ShootOut mode accredited workshop you select. This also means that results from different cars, measured on different dynos can be compared much more accurately which opens a lot of insight to power readings.
ShootOut was developed by Dyno Dynamics primarily to eliminate "Operator Technique" and as a tool for measuring horsepower accurately and CONSISTENTLY for ALL Dyno Dynamics dynos with Shootout accreditation. All dynos with Shootout accreditation have been calibrated the same accross the board, and should not vary more than 1% when comparing between Dyno Dynamics dynos.
Ethical standards
All ShootOut workshops must abide by a code of practice. When a company gets its ShootOut accreditation, it is only leasing the right to use the ShootOut mode and the ShootOut logos on the dynos, which are bgasically the physical and interlectual property of Dyno Dynamics. We are bound by a contractual agreement which is renewed on a yearly basis with very strict guidelines and procedures whenever we use the ShootOut logos on printed dyno graphs. If a company does not adhere to these guidelines, and decides to employ "Operator Techniques" and manipulate the ShootOut process, Dyno Dynamics will issue the company with a warning. After 3 warnings, the company loses their ShootOut Accreditation. Dyno Dynamics expect Dyno Operators to be honest and follow the required procedures in accordance with the ShootOut Agreement between the operator and Dyno Dynamics.
Proof of integrity
1. All ShootOut graph runs must be supervised by an accredited ShootOut scrutineer.
2. When the Shootineer is confident that the run has been performed to Dyno Dynamics’ ShootOut standards, the approved ShootOut logo will be added to the graph.
3. Test conditions and other data is printed on the lower edge of the graph as further evidence of accuracy.
4. When the graph is printed, the Shootineer will apply the official ShootOut stamp and personally sign it.
5. As final proof, the customer is provided with a checklist to verify that all steps in vehicle preparation for the test have been carried out correctly.
Whether you are planning on attending a ‘head to head’ dyno day, or want your vehicle tested to verify the effects of a performance enhancement – A Dyno Dynamics ShootOut accredited workshop will determine the figures accurately, time after time, regardless of location.
The ShootOut mode system is not just a hardware or software upgrade – it is a standardised approach to power measurement, designed to ensure that you can take your car to any accredited workshop and get accurate power measurements for your car. The results will be the same regardless of which ShootOut mode accredited workshop you select. This also means that results from different cars, measured on different dynos can be compared much more accurately which opens a lot of insight to power readings.
ShootOut was developed by Dyno Dynamics primarily to eliminate "Operator Technique" and as a tool for measuring horsepower accurately and CONSISTENTLY for ALL Dyno Dynamics dynos with Shootout accreditation. All dynos with Shootout accreditation have been calibrated the same accross the board, and should not vary more than 1% when comparing between Dyno Dynamics dynos.
Ethical standards
All ShootOut workshops must abide by a code of practice. When a company gets its ShootOut accreditation, it is only leasing the right to use the ShootOut mode and the ShootOut logos on the dynos, which are bgasically the physical and interlectual property of Dyno Dynamics. We are bound by a contractual agreement which is renewed on a yearly basis with very strict guidelines and procedures whenever we use the ShootOut logos on printed dyno graphs. If a company does not adhere to these guidelines, and decides to employ "Operator Techniques" and manipulate the ShootOut process, Dyno Dynamics will issue the company with a warning. After 3 warnings, the company loses their ShootOut Accreditation. Dyno Dynamics expect Dyno Operators to be honest and follow the required procedures in accordance with the ShootOut Agreement between the operator and Dyno Dynamics.
Proof of integrity
1. All ShootOut graph runs must be supervised by an accredited ShootOut scrutineer.
2. When the Shootineer is confident that the run has been performed to Dyno Dynamics’ ShootOut standards, the approved ShootOut logo will be added to the graph.
3. Test conditions and other data is printed on the lower edge of the graph as further evidence of accuracy.
4. When the graph is printed, the Shootineer will apply the official ShootOut stamp and personally sign it.
5. As final proof, the customer is provided with a checklist to verify that all steps in vehicle preparation for the test have been carried out correctly.
Whether you are planning on attending a ‘head to head’ dyno day, or want your vehicle tested to verify the effects of a performance enhancement – A Dyno Dynamics ShootOut accredited workshop will determine the figures accurately, time after time, regardless of location.
I'm so tired of seeing dyno graphs with no data. I mean seriously... why is there not a ton of data at the bottom of every graph showing air intake temps, correction factors, modes of operation, etc.
Nov 8, 2007, 04:47 AM
#66
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Do you guys really think it's that hard for dynos to make repeatable results even at different shops? I mean seriously are we lacking the technology to do that? We're not... if every DynoDynamics shop would run in Shootout Mode then I honestly believe you could trust that the same car could dyno at a different shop and get pretty much the exact same result.
Taken from: http://www.xspeed.com.au/tech_features.php?tech_id=19
I'm so tired of seeing dyno graphs with no data. I mean seriously... why is there not a ton of data at the bottom of every graph showing air intake temps, correction factors, modes of operation, etc.
Taken from: http://www.xspeed.com.au/tech_features.php?tech_id=19
I'm so tired of seeing dyno graphs with no data. I mean seriously... why is there not a ton of data at the bottom of every graph showing air intake temps, correction factors, modes of operation, etc.
Nov 8, 2007, 05:59 AM
#71
So I think there is some basis for us evo owners wanting dyno results to be repeatable and consistent between shops.
Nov 8, 2007, 06:02 AM
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In a recent article printed in March 2006 issue HOTROD Magezine, Mark Dobeck the creator of DYNOJET spilled the beans on the “fudge-factor”.
Here is a quote from that article:
“One of the biggest headaches of DYNOJET’s go-it-alone chassis-dyno project was figuring out how to assign meaningful power numbers in the face of unknown inertia from the moving parts of the hundreds or thousands of engine, driveline and tire combinations. Wrestling to fully understand inertia and powertrain losses, Dobeckand his team quickly realized that the standard physics formula of weight, time, and distance for converting acceleration into horsepower simply didn’t work----the derived number was always lower than accepted numbers. They poured on resourses and burned up time and money investigating it, but no matter what they did, the math never added up.
DYNOJET’s final number-fudge was arbitrarily based on a number from the most powerful raod-going motorcycle of the time, the ’85 1,200cc Yamaha Vmax. The Vmax had 145 advertised factory horsepower, which was far above the raw 90HP number spit out by the formula. Meanwhile, existing aftermarket torque-cell engine dynamometers delivered number that clustered around 120. Always a pragmatist Dobeck finally ordered his chief Engineer to doctor the math so that the DYNOJET 100 measured 120HP for a stock Vmax. And that was that: For once and forever, the power of everything else in the world be relative to the ’85 Yamaha Vmax and a fudged imaginary number. Dobeck’s engineering staff was dismayed by the decision, but the DYNOJET 100 exclusively measured surplus power available to accelerate the vehicle’s mass – no more , no less – and that was true even if the modification was a low inertia flywheel or lightweight wheels.”
So the next time you want to compare your DYNOJET HP numbers to other chassis dyno’s, you must consider that your DYNOJET numbers are at an unfair “fudged” advantage.
To be honest all dyno's have too many ways to manipulate the #'s coming from them and in most cases its not the tuner or operators fault the #'s are not correct but in most cases its the fault of the person or people that set up the dyno and software for the shop running the dyno for not fully schooling the operator on the machine and even sometimes for not setting the software correctly to that specific drum mass.
Here is a quote from that article:
“One of the biggest headaches of DYNOJET’s go-it-alone chassis-dyno project was figuring out how to assign meaningful power numbers in the face of unknown inertia from the moving parts of the hundreds or thousands of engine, driveline and tire combinations. Wrestling to fully understand inertia and powertrain losses, Dobeckand his team quickly realized that the standard physics formula of weight, time, and distance for converting acceleration into horsepower simply didn’t work----the derived number was always lower than accepted numbers. They poured on resourses and burned up time and money investigating it, but no matter what they did, the math never added up.
DYNOJET’s final number-fudge was arbitrarily based on a number from the most powerful raod-going motorcycle of the time, the ’85 1,200cc Yamaha Vmax. The Vmax had 145 advertised factory horsepower, which was far above the raw 90HP number spit out by the formula. Meanwhile, existing aftermarket torque-cell engine dynamometers delivered number that clustered around 120. Always a pragmatist Dobeck finally ordered his chief Engineer to doctor the math so that the DYNOJET 100 measured 120HP for a stock Vmax. And that was that: For once and forever, the power of everything else in the world be relative to the ’85 Yamaha Vmax and a fudged imaginary number. Dobeck’s engineering staff was dismayed by the decision, but the DYNOJET 100 exclusively measured surplus power available to accelerate the vehicle’s mass – no more , no less – and that was true even if the modification was a low inertia flywheel or lightweight wheels.”
So the next time you want to compare your DYNOJET HP numbers to other chassis dyno’s, you must consider that your DYNOJET numbers are at an unfair “fudged” advantage.
To be honest all dyno's have too many ways to manipulate the #'s coming from them and in most cases its not the tuner or operators fault the #'s are not correct but in most cases its the fault of the person or people that set up the dyno and software for the shop running the dyno for not fully schooling the operator on the machine and even sometimes for not setting the software correctly to that specific drum mass.
Nov 8, 2007, 06:27 AM
#73
Guys there is one answer to all of this. Only go to Dyno-Dynamics Shootout Mode accredited dynos. Only problem is.. I don't know if one even exists in the USA. LoL.
All the conditions and settings and temperatures and tire pressures are there on your dyno sheet. Then you can know your sheet is from the machine itself no operator error.
All the conditions and settings and temperatures and tire pressures are there on your dyno sheet. Then you can know your sheet is from the machine itself no operator error.
Nov 8, 2007, 06:56 AM
#74
I think something that was touched on but wasn't really given it's importance is boost recovery. This is something that I have a lot of knowledge of.
My car dyno'd at 420whp on chad blocks dyno, but the problem with ANY dyno is that it's only one gear, so my boost recovery issues weren't there to show their ugly face.
At the track running a vent to atmosphere blow off valve (tial 50mm) hindered boost recovery, to top this off, I'm like the slowest shifter ever. With both of these issues I trapped 120mph.
Now I have an APS BOV and have added tephra's lift to shift mod to my ecu. Currently I'm on pump gas (26psi), but honestly the car "feels" faster, and to prove that I recently raced a 460whp/480tq 03 Cobra (pullied cobras trap in the low 120s setup like this one is). He beat me by a fender to 120 from a 40mph roll. I utilized the Tephra nlts during this race, without it I would have lost by atleast 2 car lengths. The main difference??? I see no less then 15-18psi inbetween shifts, where with lift shifting I would see vacuum in the shift.
My hypothesis is this: On pump gas only I will see 120ish mph traps with decent sub 1.75 60 foots.
I plan to expiriement to prove my hypothesis on Saturday, weather permitting.
My car dyno'd at 420whp on chad blocks dyno, but the problem with ANY dyno is that it's only one gear, so my boost recovery issues weren't there to show their ugly face.
At the track running a vent to atmosphere blow off valve (tial 50mm) hindered boost recovery, to top this off, I'm like the slowest shifter ever. With both of these issues I trapped 120mph.
Now I have an APS BOV and have added tephra's lift to shift mod to my ecu. Currently I'm on pump gas (26psi), but honestly the car "feels" faster, and to prove that I recently raced a 460whp/480tq 03 Cobra (pullied cobras trap in the low 120s setup like this one is). He beat me by a fender to 120 from a 40mph roll. I utilized the Tephra nlts during this race, without it I would have lost by atleast 2 car lengths. The main difference??? I see no less then 15-18psi inbetween shifts, where with lift shifting I would see vacuum in the shift.
My hypothesis is this: On pump gas only I will see 120ish mph traps with decent sub 1.75 60 foots.
I plan to expiriement to prove my hypothesis on Saturday, weather permitting.
Nov 8, 2007, 06:58 AM
#75
Something I didn't take account for however "comma" was that the cobra would be more traction limited and have worse 60 foots wich would inflate the trap speed.....guess saturday ill just have to go see