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[Dusty]

I just want to know why the numbers don't add up. To say that and then not explain is frustrating. Bryan and my numbers are close but different in spots but not much. It would be nice if someone who really understands the relationship between the numbers could explain. What's not adding up to what and why doesn't it?
I'll try again today to get my numbers up.



Don't do anything mellow after whiskey.....Seal & Croft or was if Logins and Messina

[bgreer]

I just want to know why the numbers don't add up. To say that and then not explain is frustrating. Bryan and my numbers are close but different in spots but not much. It would be nice if someone who really understands the relationship between the numbers could explain. What's not adding up to what and why doesn't it?
I'll try again today to get my numbers up.



Don't do anything mellow after whiskey.....Seal & Croft or was if Logins and Messina

  Interesting that there are no responses, and also interesting that no one has said your numbers are false, when they are higher than mine, and also interesting that no one has called you a liar and that you have made "Outlandish Claims" regarding your bike. Maybe the correction factor is some kinda trade secret, something us commoners couldn't understand. And maybe we should forget about the dyno and plan a track day and line 'em up...I'll race till I blow the BIOtch up, then I'll pay Third Coast Speed to rebuild it with a big bore kit dual air and NOS, then do it again. Sounds like fun to me. Whers all the JC cheerleaders now??

[johnnycheese]

I just love it when some people read into things that are not there

let us try it one more time and see if you can this at face value this time.


the GAINS!!!!!!!! are real.
is this part understood??

The numbers are not, due to a correctoin factor of less than 1.0


let me explain it another way...
a boy with slip ons said his bike make 180hp when mapped with slip ons. a stock Busa makes between 147-163 stock,
Fact is everyone knows slip ons make 2-3 hp max gain.
where did the 180 number come from???
the correction fator said the dyno was at 7500 feet and was really at 1400 feet.
but he differance in curves on the before mapping and after mapping is correct just the numbers are not.

[johnnycheese]

4th gear pull?

[bgreer]

I just love it when some people read into things that are not there

let us try it one more time and see if you can this at face value this time.


the GAINS!!!!!!!! are real.
is this part understood??

The numbers are not, due to a correctoin factor of less than 1.0


let me explain it another way...
a boy with slip ons said his bike make 180hp when mapped with slip ons. a stock Busa makes between 147-163 stock,
Fact is everyone knows slip ons make 2-3 hp max gain.
where did the 180 number come from???
the correction fator said the dyno was at 7500 feet and was really at 1400 feet.
but he differance in curves on the before mapping and after mapping is correct just the numbers are not.

  I appreciate your explanation Johnny, thats all we are asking for. If you don't mind explain what the correction factor is correcting, and how the temp in the shop makes a difference...Dust's and my correction factor was different when we compared our sheets last night and the temps were within 5* of each other....is the correction factor for the machine itself? or is it forth difference between crank and wheel power?

[bgreer]

4th gear pull?

  sorry, you posted that while I was typing  4th gear pull?

[hooter]

Muffmaster Vs Bgreer....It's Awwwwn.

I sure hope the rain is gone tomorrow, I can't spend another full day doing this.

I can't spend another full day doing this

Why not? It's always fun reading and letting your imigaination visualize the facial expressions and hearing the untyped words.  

Hey Muff,  You better stay at home and Peddle you puppies.  

[hookem]

I, for one, have no understanding of what the "correction factor" is, or what the "corrected wheel hp" is.  Not that I don't care, just that it has not been anything I have had truly explained to me.  There is a thread over on the OA from Brent about dyno stuff.  Something about the "simulated wind speed" and whatever else....

All I am getting at is this:  it seems to me that what these graphs and numbers say is some inside secret or is something that is constantly variable, based on the machines, the people operating the machines, the temperature, the wind speed. etc.  All I know for certain was the look on Dusty Bill's face when he was telling me yesterday about how badly Bryan AND Patti just simply dusted him.  Now, all I know is that Bryan went in looking to improve his performance.  He got it.  I also know that Bill was pretty concerned about how/why Bryan was able to run away from him.  All that tells me is that Bryan has a bike that is running a notch above.

So, are the numbers true or false?  Who knows.  Perhaps a question for Johnny......  What is the correction factor correcting?  How does it play into the numbers?  Also, how reliable are the machines and what type of maintenance for them is required?  What I'm getting at there is, if a machine is often subjected to high humidity (like here near the coast), and a bike were tested on a low-humidity day, could weather conditions skew the numbers?

[Dusty]

I just love it when some people read into things that are not there

let us try it one more time and see if you can this at face value this time.


the GAINS!!!!!!!! are real.
is this part understood??

The numbers are not, due to a correction factor of less than 1.0


let me explain it another way...
a boy with slip ons said his bike make 180hp when mapped with slip ons. a stock Busa makes between 147-163 stock,
Fact is everyone knows slip ons make 2-3 hp max gain.
where did the 180 number come from???
the correction fator said the dyno was at 7500 feet and was really at 1400 feet.
but he differance in curves on the before mapping and after mapping is correct just the numbers are not.

Thanks for the explanation Johnny. Forgive me for being a little slow but from your example, if I got it right, the correction factor is determined by the elevation of where the machine is set up?

So, these guys that travel around with these mobile units would have to change their correction factor every time they set up? (provided they changed elevations. And if they don't, then they could be improving the bikes performance but giving the owner fictitious numbers?

[Muffmaster]

Muffmaster Vs Bgreer....It's Awwwwn.

I sure hope the rain is gone tomorrow, I can't spend another full day doing this.

I can't spend another full day doing this

Why not? It's always fun reading and letting your imigaination visualize the facial expressions and hearing the untyped words.  

Hey Muff,  You better stay at home and Peddle you puppies.  

Hell if I take my bags, windshield and rear seat off I should gain 10 HP!! But I better wait till it gets warmer then his settings will be off and I'll have an advantage cause I dyno'd mine in July (Damn this is fun)

[bgreer]

  Though we appreciated Johnny's response, I guess Dusty and I were looking for a more detailed explanation. We have both been researching this, and Dusty's research bore more fruit than mine...her it is, read into it what you will.

http://www.cvoharley.com/smf/index.php?topic=162.470;wap2

....and for those of you that don't like to link, I'll copy and paste what I found relevant


Beat the Drum The crooked dyno operator can reprogram the weight of the drum, which will allow the dyno to create anomalous power numbers.

Change Load Changing the load by tightening or loosening the tie-down between runs can compromise any comparisons made with the dyno testing.

Messing With the Weather This is where the dyno operator has to be extremely devious. If you mess with the readings that the computer uses to calculate the correction factor, you can alter the corrected output significantly. The one reading that the built-in sensors do not take automatically is humidity. The dyno operator has to enter the humidity correction themselves. Since the humidity is manually entered into the computer it is the easiest to alter. While humidity numbers are obviously suspect, the temperature can be faked pretty easily as well. Another good way of bumping up the power figures is by "playing about" with the air temperature and pressure corrections. If you dial in your own "standard" conditions as being freezing cold with the barometer going off the scale, or you put the temperature probe near the engine, you can get the system to add huge amounts of power to what was actually measured. So make sure you know if such corrections were made or not and to what standards they were made if any. We actually decided to try this one, just to see how easily it could be done.

Jackson Racing's Dynojet is set up with the weather data box mounted on a perpetually-shady portion of the dyno room wall. The temperature probe hangs under the box in the open air about two feet off the ground--right where most air intakes pull their air supply. Oscar Jackson pointed out that he has seen these boxes mounted where they were more easily accessed, and has even seen the temperature sensor hanging on a divider wall next to the computer, or in a drawer on the dyno bench. In the drawer, an unscrupulous dyno operator could put his or her hand around the sensor before doing a run, bumping the ambient temperature reading up into the 90-degree range. With it hanging on a well-placed wall, the sensor could be flipped from the shade into direct sunlight, where it could slowly bake up to a nice, warm temperature.

The wire on Jackson's sensor was only about two feet long, so we couldn't get it into the sun, and a shield prevented holding the sensor in a warm hand from having much effect. Instead, I cupped my hands around the sensor and blew on it. Within 30 seconds the dyno was reading 95 degree ambient temperatures even though our baseline run made a few minutes earlier had been in 66-degree air. We made another run with the engine breathing 66-degree air, but the dyno correcting for 95-degree air. Our corrected power jumped from 136 hp to 143 hp.

Correction factors between 0.97 and 1.03 are pretty normal. Outside that range, you should be on the lookout for large differences between the runs you are comparing.

In order for dyno results to be comparable and universally understood there are a number of things that need to be closely controlled during the measurement process: Operating Conditions - air temperature, pressure and humidity affect the amount of power an engine produces. Cold dense air means a greater mass of oxygen per power cycle and thus more power is generated (provided of course that air/fuel mixture is properly calibrated for the conditions prevailing). There are formula that can be used to calculate how much the measured power would change if the test conditions were different. This enables dyno results to be "corrected" back to standard conditions to enable comparison with anyone else's test results. Sadly however there is no one universally accepted set of "standard" conditions because different automotive bodies in different countries use different standards to calibrate to. "SAE" power standards are used in the USA and sometimes in England. "DIN" standards are used in Europe and there are a few other oddball systems just to confuse the issue. So just because your car is rated at 100 bhp and a friends at 110 bhp doesn't necessarily mean that his engine is more powerful - it depends whether both measurements were corrected to the same standard conditions.

From Short Block Charlie 7/24/04 One of the big problems I see with dyno charts is the following. Was the dyno test performed in a dyno cell? A dyno cell is designed to input air and remove exhaust for proper tests. If not, you will see false readings. Very few dyno facilities have this, such as the traveling dyno tuners. The dyno has the capableness to compensate for humidity and elevation to record corrected information. The other problem I have with my own customers is they will get a dyno sheet that is not impressive, but bike runs like rocket ship. There is a lot of magic out there to fool the consumer.

BaggerDad:
Continuation of post #473

An engine's output depends on the quality of air it breathes, and it is therefore essential to take into account variances in air pressure, temperature and humidity when measuring horsepower. Raw numbers are generally normalized to sea level conditions within a dynamometer's software using a standard correction factor. However, this does not mean you will get identical readings from two different dynos, or for that matter, the same dyno on two different days. While the dynamometer corrects the horsepower it reads to standard atmospheric conditions, it cannot account for jetting changes you should have made to account for the weather. For example, you could run your bike at the local dyno and see 100 corrected horsepower on a cold day and return--without changes--on a hot day for another run and get 98 corrected horsepower. Where's the two horsepower? To get back to 100 horsepower, you'd have to lean your bike out for the hotter weather. Because different weather conditions can result in different air densities and different oxygen concentrations, the weather can have a significant effect on power output. The SAE has a standard set of correction factors that can be used to normalize all power outputs to what they would be at sea level, on a 60 degree day, with 0 percent humidity. Every Dynojet has a small weather station built in to feed the appropriate temperature and barometric pressure readings to the computer so it can calculate this factor. The difference between 0 percent and 100 percent humidity is about a seven percent correction. A temperature change from 60 to 90 degrees, on the other hand, will have an effect of about a 2.8 percent. A difference in elevation from sea level to 5000 feet is worth a whopping 20 percent!

Operating Conditions Altitude, air temperature, pressure and humidity affect the amount of power an engine produces. The only thing to really worry about is the A to B changes on the same bike, same dyno, same day.
Sometimes you may want to know how much power you are really making on that specific day due to the temperature, humidity and pressure on that day; in that case, you should look at the uncorrected power readings.
When you want to see how much more power you have solely due to the new exhaust or the new cam, then you will find that the corrected power is more useful. It removes the effects of the temperature, humidity and atmospheric pressure and just shows you how much more (or less) power you have than in your previous tests.

Altitude As you increase your altitude the octane requirement decreases 1-2 octane per 3000 feet elevation. This is because the density of the air is reduced or there is less air available for your motor to burn. The higher the altitude, the richer your motor will run, making it necessary to re-jet the motor in order to lean it out. The fuel volume remains the same and the air volume goes down. If you have a vacuum advance, as the altitude increases, the motor makes less vacuum and the air fuel ratio becomes richer due to the decreasing air to fuel volume. Altitude and weather systems change the air's pressure. As you go higher, the air pressure decreases from around 1,000 millibars at sea level to 500 millibars at around 18,000 feet. Most of us race at less than 1000 feet of elevation. Weather systems that bring higher or lower air pressure also affect the air's density, but not nearly as much as altitude. Air density is lowest at a high elevation on a hot day when the atmospheric pressure is low, say in Denver when a storm is moving in on a hot day. The air's density is highest at low elevations when the pressure is high and the temperature is low, such as on a sunny but extremely cold, winter's day in New Hampshire. Humidity and air density Most people who haven't studied physics or chemistry find it hard to believe that humid air is lighter, or less dense, than dry air. How many times have you heard someone tell you to add more gear on a hot humid day because it is harder to push the kart through the hot humid air. The inverse is really true, the kart flows easier through the air but the pressure needed to fill the cylinder with the proper air fuel mixture is lessened by lowered air density.

Temperature When the temperature goes up, the air density decreases, thus you have less air available for combustion and your air fuel ratio becomes richer. The same works in reverse. As the temperature goes down, you end up with more air per cubic foot, and without re-jetting your carburetor, the engine will run leaner.

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[bgreer]

  My correction factor was .971 and Dusty's was .989 (I think)...what I get from this is that ANY operator can skew the results to what ever he desires as per his needs. The correction numbers are within the "norm" as per the article posted above....what I also get from this is that Johnny's statement that the correction factor is wrong, without him being there, without observing technique, without knowing exact temp and humidity conditions in the shop and where temp probes and phychrometers (to read humidity and dew pt.) are placed, then his comment was flawed.

[bgreer]

  On the other hand, if Third Coast Speed calculations were off in the slightest, the numbers COULD be wrong. No real way of knowing all this...I guarantee the next time I get my bike Dyno'd all these factors will be considered. All things considered, all personal attacks and BS aside, I still suggest a track day and we'll line 'em up and see what happens.

[jmdaniel]

This should settle it once and for all:



Note however, that certain factors in the testing environment can affect the final measurement. These factors can include, but are not limited to:

• temperature of the testing room
• amount of alcohol in the system, especially whiskey
• attractiveness of the person measuring, if test is not self-performed
• if test is self performed, availability of inspirational materials, such as Playboy, Hustler, Field and Stream, etc...
• if self performed, propensity of person to lie about results of test (experience shows that this factor should be weighted heavily)

 

[RD]

Now Jeff, is that to scale? I mean, if I printed it out on an 8 1/2 x 11 sheet of paper....err, never mind.