DYNO TESTING

[Floridaliner]

 I have BIG cement power poles near me on a back road "closed pro course"  that are 1/10 mile apart. I can hit just about 90mph in between those poles without my Dresser garb on the bike. That is f-kin fast. 

[RoadStarRaider]

[Floridaliner]

 Heres a nice write up:

Dyno Correction Factor and Relative Horsepower
 

So what's all this correction factor stuff anyway??

The horsepower and torque available from a normally aspirated internal combustion engine are dependent upon the density of the air... higher density means more oxygen molecules and more power... lower density means less oxygen and less power.

The relative horsepower, and the dyno correction factor, allow mathematical calculation of the affects of air density on the wide-open-throttle horsepower and torque. The dyno correction factor  is simply the mathematical reciprocal of the relative horsepower value.

Originally, all of the major US auto manufacturers were in or around Detroit Michigan, and the dyno reading taken in Detroit were considered to be the standard. However, as the auto industry spread both across the country and around the globe, the auto manufacturers needed a way to correlate the horsepower/torque data taken at those "non-standard" locations with the data taken at the "standard" location. Therefore, the SAE created J1349 in order to convert (or "correct") the dyno data taken, for example, in California or in Tokyo to be comparable to data taken at standard conditions in Detroit.

What's it good for?

One common use of the dyno correction factor is to standardize the horsepower and torque readings, so that the effects of the ambient temperature and pressure are removed from the readings. By using the dyno correction factor, power and torque readings can be directly compared to the readings taken on some other day, or even taken at some other altitude.

That is, the corrected readings are the same as the result that you would get by taking the car (or engine) to a certain temperature controlled, humidity controlled,  pressure controlled dyno shop where they measure "standard" power, based on the carefully controlled temperature, humidity  and pressure.

If you take your car to the dyno on a cold day at low altitude, it will make a lot of power. And if you take exactly the same car back to the same dyno on a hot day, it will make less power. But if you take the exact same car to the "standard" dyno (where the temperature, humidity and pressure are all carefully controlled) on those different days, it will always make exactly the same power.

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.

But when you want to see how much more power you have solely due to the new headers, or the new cam, then you will find that the corrected power is more useful, since 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.

There is no "right" answer... it's simply a matter of how you want to use the information.

If you want to know whether you are going to burn up the tranny with too much power on a cool, humid day, then go to the dyno and look at uncorrected power to see how exactly much power you have under these conditions.

But if you want to compare the effects due to modifications, or you want to compare several different cars at different times, then the corrected readings of the "standard" dyno will be more useful.

[Floridaliner]

 Alright lunch is over back to Dyno 101......... 

I was looking at Dyno sheets on Raider performance.com .  That number on the right lower bottom of the sheets, I believe that is the efficiency factor givin for loss.  Is that correct?  So I am getting .95 reading of my power, SAE uncorrected, tire probably slipping by looks of trq lines. I gotta figure that bumpity line in the trq spin up.

 
 

[eric ray]

I have a 300mm fat tire kit, do you believe this will be a factor in my test???

[Floridaliner]

I have a 300mm fat tire kit, do you believe this will be a factor in my test???

 I would say it depends on the contact patch width.

[TRaider_John]

Belive it or not, the contact patch will be the same if the rear tire pressure is the same.  The weight of the bike is divided over the same number of square inches regardless of the tire size.  The patch may change shape, but area x pressure = force.

The diameter of the 300 is larger than a 240 so the torque arm will be a little longer and that means a little less force will be seen by the Dino drum.  that will drop your numbers a little bit, but the shape is what you need to focus on and not the actual numbers. 

[prostkr]

http://www.dynojet.com/downloads/software.aspx   here is the free software. Here is a file to play with from my car.    http://www.mediafire.com/?071w4qbmhabq4am

The dyno guy should be able to email you the file. Its stored on his computer. I usually take a jump drive with me and ask for them all.

[Floridaliner]

 Cool thanks........... 

[Budzo]

Belive it or not, the contact patch will be the same if the rear tire pressure is the same.  The weight of the bike is divided over the same number of square inches regardless of the tire size.  The patch may change shape, but area x pressure = force.

The diameter of the 300 is larger than a 240 so the torque arm will be a little longer and that means a little less force will be seen by the Dino drum.  that will drop your numbers a little bit, but the shape is what you need to focus on and not the actual numbers. 

Correct me if my theory is incorrect, but I would think a larger tire and rim results in greater rotational weight which will use up horsepower, resulting in lower numbers than the same bike with a stock rear tire.

[Floridaliner]

 I kinda like the low number now. When I race someone next time and beat them, I can say I have only 88hp and I am hauling 1000lbs, go figure that one out.  

[Floridaliner]

Belive it or not, the contact patch will be the same if the rear tire pressure is the same.  The weight of the bike is divided over the same number of square inches regardless of the tire size.  The patch may change shape, but area x pressure = force.

The diameter of the 300 is larger than a 240 so the torque arm will be a little longer and that means a little less force will be seen by the Dino drum.  that will drop your numbers a little bit, but the shape is what you need to focus on and not the actual numbers. 

Correct me if my theory is incorrect, but I would think a larger tire and rim results in greater rotational weight which will use up horsepower, resulting in lower numbers than the same bike with a stock rear tire.

I have seen a calc on tire size for Drag racers. I will look for it. But your are spinning a gyro effect so it should roll even better once it gets rolling, it has more weight to slow down too.

[dchertz]

I kinda like the low number now. When I race someone next time and beat them, I can say I have only 88hp and I am hauling 1000lbs, go figure that one out.  

haha

[Budzo]

Belive it or not, the contact patch will be the same if the rear tire pressure is the same.  The weight of the bike is divided over the same number of square inches regardless of the tire size.  The patch may change shape, but area x pressure = force.

The diameter of the 300 is larger than a 240 so the torque arm will be a little longer and that means a little less force will be seen by the Dino drum.  that will drop your numbers a little bit, but the shape is what you need to focus on and not the actual numbers. 

Correct me if my theory is incorrect, but I would think a larger tire and rim results in greater rotational weight which will use up horsepower, resulting in lower numbers than the same bike with a stock rear tire.

I have seen a calc on tire size for Drag racers. I will look for it. But your are spinning a gyro effect so it should roll even better once it gets rolling, it has more weight to slow down too.

Makes sense.

[RAIDERIDER]

Ive been riding a long time & for me would not consider knowing the HP numbers of a bike that only delivers 100 horses, now if i have a bike that is around the 200HP mark then i would be into it.

  All i know is that the Raider is a beast in the Low Range & Mid Range is Good , thats all i need to know       If iam running lean & fry a piston that gives me a darn good reason to really build this motor into the 150 HP beast it one day will be .

[Floridaliner]

 It is a beast.  I have been searching around Youtube and sites like HDforums, they like to say "this is SAE numbers folks" they failed to say SAE CORRECTED which is like STD numbers. LOL.... I would have 100+hp and 120+trq too on SAE Corrected or STD.

 I am gonna talk to my shop again in a few weeks, after Christmass, and plan a build for power with him.