Dyno Questions??

[Colorado700R]

Since seeing the dyno sheets in LS, OK and dynos here and elsewhere, how can there be such a major difference between dyno readings?


Why does a Superflow DYno used by the folks at Advantage Tuning and Racers Edge have to be "corrected" to show Dynojet numbers?  Aren't they reading the same force?  are they loaded different?  Is there an advantage to one style or the other for tuning?

Here's my dyno sheet from Advantage tuning on the Superflow



Here's the same run with Dynojet "Corrected" #'s






I've heard that tuners can actual manipulate their dynos to read low or higher...why would they do this?  Is this just a way to either have high #'s for customer satisfaction, but what about a "heartbreaker"?  Does a dyno reading constantly lower than others mean it's always the more accurate?


I can understand between here in CO. vs LS OK. or southern CA.  there's a major difference in Alt. but why the major deltas between HP #s in shops within the same zipcodes?

I also get the atmospheric pressure, humidity, and temp. differences, along with dyno tires etc. But some of these major differences we see don't make sense IMO.

Aaron

[russ-russ]

Good question Aaron.  I'm curious to see what the input will be from guys like Daniel, Kam, Paul, Bo, Kenny, Tim, Jason  that's all I can think of.

[DL700]

dynojet has been the leader in DYNAMOMETERS for a long time and have set the BASE or correction software based on temp air pressure and humidity....as many other software programs let the uses manipulate the input settings allowing the settings/calibration of actual input to be trown off as in the past where TRINITY racing Dyno was abour 25% high where now it is right back on track with all the other Superflows...


Dynojet uses a percentage number to show actual correction... here we range from 1.08 to 1.12 CF... 1.0 being see level @ ## * and ## humidity.

[Pw383426]

Unfortunately there's not really a "standard" in dynos, like in other industries in life. There's STD and SAE correction factors, but still no overhead of how they have to read.

Superflows have a "dynojet" correction factor so they can try to read "higher" like a dynojet. But unfortunately Dynojet dynos are all over the place for readings as well so the DJ correction factor is a little odd. Where you can go from a higher reading dyno (this isn't to be taken offensively) such as the Rocket Factory dyno, and then go to Roosterbuilt and get a completely different reading.... even though they're both dynojets they aren't even close to each other.

As far as manipulation of numbers goes, that's a whole nother story. Superflow's obviously are much easier to manipulate due to their different correction factors, where as it's much more difficult to manipulate a dynojet. But here is where lies the problem with manipulation, you're not just lying to the customer about their numbers to reach a specific target (and everyone knows reputation is EVERYTHING in this business) but you're also lying to yourself. To make building race bikes a science, takes as many inputs as possible, with X compression or X cam.... it becomes pretty simple to figure out what works and what doesn't, that's why building performance parts is so crucial to dyno tuning, because it shows you the results 10x's faster and easier than testing on tracks only. I worked with a Superflow dyno for about a year, and my specific experience with that dyno was that it read on par with the "average" dynojet, but when using the dynojet correction factor it read too high.... but like dynojets I'm sure Superflows are just as much all over the charts.

Of course, that's just what goes along with Chassis dynos and the countless variables between them and bike to bike.

Here's a post off another site

first off... i want to post up a copy a of a good info post by Randy Lyman\ RL Speed \owner of Randy's Ring and Pinion ... student of Ron Hamp's school of airflow..and SuperFlow dyno owner:

John,

Superflow dyno outputs can be manipulated in several ways - I only know of two easy ways to manipulate a Dynojet dyno.

Based on what I have seen and what I have been told, I believe DynoJet dynos can be manipulated through barametric preasure calibration and by entering a different inertia weight number.

Superflow dynos can be manipulated through barametric preasure, air temp, changing the inertia weight value for drivetrain/tires, smoothing factors, and by changing the number for the "DynoJet correction factor". If I remember correctly, a person can also change equations to use a false inertia weight on a SF, or even enter their own additional "correction factors" to the basic equations that calculate HP & Torque.

I have done a lot of calibration runs comparing the inertia results and eddie current results on my SuperFlow. I am confident my SAE corrected numbers are fairly accurate for both. I have compared my dyno to other dynos by running the same bike on other dynos on the same day or within a few days and I am fairly confident my DynoJet/SAE "corrections" give me numbers that compare very closely to three DynoJet dynos. As I stated earlier, the correction factor that I have found to work for me is approximately 13% -- my SAE #'s x 1.134

The bottom line is that the numbers can be manipulated and IMO the integrity of the numbers is only as good as the Integrity of the dyno operator and their understanding of the entire process.

Randy

[RaptorRandy]

higher reading dyno (this isn't to be taken offensively) such as the Rocket Factory dyno, and then go to Roosterbuilt and get a completely different reading.... even though they're both dynojets they aren't even close to each other.

That's because RF is using an older version of the Winpep software.......apples to oranges. All the newer up to date eddie current Dynojet dyno's should be reading within 2% of each other, if there not, then somethings amiss.





Randy

[DL700]

higher reading dyno (this isn't to be taken offensively) such as the Rocket Factory dyno, and then go to Roosterbuilt and get a completely different reading.... even though they're both dynojets they aren't even close to each other.

That's because RF is using an older version of the Winpep software.......apples to oranges. All the newer up to date eddie current Dynojet dyno's should be reading within 2% of each other, if there not, then somethings amiss.





Randy

the older software can be way out of wak and needs to be updated,,, i dont even see how someone can function efficently with that.... ... but it is possible it  isnt the right software for that specific drum serial  number

[Colorado700R]

So what are some good questions to ask when going to a dyno?  Software versions? Drum employed?  What else?

[DL700]

what are you trying to achieve?  


... Best question is to ask if "THEY" and just doing POWER pulls or are going to do a FULL REMAP at all TPS positions.....
...maybe ask what their most important goal of tuning your bike is? POWER or A/F...answer should be BOTH with GREAT rideability.....
...ask if they have a Baseline run of a STOCK 700 r as a good comparison and gauge of your gains over stock.....
...ask if they are tuning your ignition controller....
...ask if they are doing 4th or 5th gear pulls, as the speed sensor will come into play (i'd disconnect this before hitting the dyno) unless running a dynatek....


when they are all done, ask why your power curve looks like a rainbow

[Colorado700R]

what are you trying to achieve?  


... Best question is to ask if "THEY" and just doing POWER pulls or are going to do a FULL REMAP at all TPS positions.....
...maybe ask what their most important goal of tuning your bike is? POWER or A/F...answer should be BOTH with GREAT rideability.....
...ask if they have a Baseline run of a STOCK 700 r as a good comparison and gauge of your gains over stock.....
...ask if they are tuning your ignition controller....
...ask if they are doing 4th or 5th gear pulls, as the speed sensor will come into play (i'd disconnect this before hitting the dyno) unless running a dynatek....


when they are all done, ask why your power curve looks like a rainbow

I'm trying to compile questions to ask for future dyno customers to quantify the results.
the majority of people who read forums are in a decision process of what parts to get from where.  Inaccurate results, even with a baseline can skew these decisions.  
IE if one dyno reads total HP of a stock rappy at 38 hp, another at 42 hp.  
The 42 hp dyno will also read a higher HP increase with a particular part, so whereas the 38hp dyno might show a 2 hp increase at peak and 4 hp increase in over rev, the 42 hp reading dyno might read a 3.5 hp increase with a 5 1/2 gain in over rev.
When customers are trying make the best decisions for their applications, the more information to qualify dyno results the better.
Since funds are usually finite for most people modifying their quad, quality (properly caveatted ) information IS power.

It just amazes me how 1 HP = 550 ft·lbf/s can be convoluted so much