frEEk
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ummm... yeah
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posted May 06, 2004 12:45 PM
 Edited By: frEEk on 6 May 2004 13:46
Standard HP reporting practice
In the interest of eliminating confusion and misinformation, let's set a standard on reporting dyno readings shall we? I certainly won't suggest something as unrealistic as all reported dyno readings should be made under indentical conditions, but let's at least include full disclosure of the variables that affect dyno readings when we post "my bike made 148hp". The variables are pretty much all covered in this thread which I personally think everyoen should read, or at least the conclusion at what is currently the end of the thread. This should be enough to make anyone understand why and how dyno readings vary.
/board/viewthread.php?FID=1&TID=8536
So what I'm suggesting here is when you list any HP numbers, please include:
- Correction factor (SAE, STD, uncorrected, etc)
- Environmental conditions (altitude, humidity, temperature)
- Model of dyno used (dynojet 150, 250, Factory Pro, Superflow)
- What mode the measurement was taken in (inertia test or steady state test)
- Was the bike strapped or was there a rider on the bike (weight of rider/tightness of straps is an issue too)
- How much air was in the tire
- If an inertia test, was the tire new, worn out
- Was the chain in good condition and lubed
Many of these factors are things that should be adjusted to optimal values before taking the run (like consistent tire pressure, good condition chain), and of course some factors make a bigger difference than others. Ask your dyno operator where the equipment for measureing air temp and humidity is located also, and encourage them to move it to a better location (nearer the bike's intake) if it is badly placed (like mounted to the ceiling or tucked away in a hot or cool border). Maybe we can collectively help to educate those (hopefully few) dyno operators out there who are mising some important factors and who are handing out numbers without educating their customers as to how exactly those numbers came about. Would be nice if magazines would specify all these details when they publish their numbers too but i wouldnt hold my breath. :\
   
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VincentHill
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posted May 06, 2004 01:40 PM
Freek, the 2 things I saw that are a "MUST" were type of HP (SAE is the average standard here) and type of Dyno (The DJ 150 does read low and the 200 a little better and the 250 is what is mostly in use nowadays.
That new style Dyno (Really not new, just new in use) really reads closer to Std HP.
If the person does not lube the chain and has it tight and using a Worn tire, this can be used as an "Excuse" more than a variable. The "Correction Factor" is supposed to adjust for Humidity and air temp along with Barometer pressure.
One thing left out is the fuel. Pump or Oxygenated!
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k bryant
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posted May 06, 2004 02:03 PM
Jeez Vince, now you're expecting them to admit they're running funny gas to energize their readings! 
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entropy
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posted May 06, 2004 02:29 PM
std reporting on hp???
nah...
I get a really good laugh outa 185hp stock engines, and such. A std method of reporting might lessen the entertainment value. 
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MadMike
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FEAR THE BLACK FLAG!!!!!!!!
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posted May 06, 2004 02:49 PM
LOL.. yea mine only ran 180HP. but runs 150 in the 1/4. hmmmmm... cool
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redelk
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Please... speak to the hand.
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posted May 06, 2004 03:16 PM
What about the smoothing? One could gain 3~5 HP depending on the smoothing factor. I believe "3" is the accepted standard.
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frEEk
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ummm... yeah
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posted May 06, 2004 04:28 PM
oh geez, another factor to consider! wouldnt it be nice if every dyno worked and read exactly the same?
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kz2zx
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posted May 06, 2004 04:40 PM
Smoothing factor is calculated how? '3' is an ambiguous term without the equation...
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pmkin10r
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posted May 06, 2004 05:54 PM
HP=vp3 / atmospheric pressure / temp. x static drag co. < 3%
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johnnycheese
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posted May 06, 2004 07:02 PM
quote:
What about the smoothing? One could gain 3~5 HP depending on the smoothing factor. I believe "3" is the accepted standard.
I use 5.
the biggest problem is the weather station for corrections
Like I have posted before it can be pouring rain and the dyno says it is 35% humidity and the temp the dyno says it is 90 when it is 80
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Michael Lee
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posted May 06, 2004 07:08 PM
Have you put yours on the dyno yet J/C?
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BA
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posted May 06, 2004 08:30 PM
I didn't realize the weather station sucked so bad!! As Tyson would say....."that's Ludicrous!"
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k bryant
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posted May 06, 2004 08:39 PM
3 is the recognized "standard". Putting it on 5 will get you the spikes that makes you happy with the largest numbers for the minisquel time it spikes.
Jeez redelk, is nothing sacred anymore. Give away all the secrets will ya......
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johnnycheese
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posted May 07, 2004 05:47 AM
quote:
3 is the recognized "standard". Putting it on 5 will get you the spikes that makes you happy with the largest numbers for the minisquel time it spikes.
Jeez redelk, is nothing sacred anymore. Give away all the secrets will ya......
you have it backwards 5 smooths it out and you get lower numbers. 1 makes it look like an earthquake
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swft
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posted May 07, 2004 05:49 AM
Zactly...
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k bryant
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posted May 07, 2004 07:39 AM
I knew that.... My bad. It was past my bedtime.... 
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extremelean
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posted May 07, 2004 07:51 AM
Isnt it past your bedtime now??
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burgerking
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posted May 07, 2004 08:38 AM
Yes indeed name all those conditions. But if you mention atmospheric pressure you should also show a certificate of the pressure transmitter anything without traceability statement is not allowed It should be traceable to NIST/NMI/NPL/BAM or equal refer the mutual agreement, www.bipm.com
And all uncertainty calculations must be done according to EA4-02 or the Guide to Uncertainty in Measurement.
Yes that will do for now, my bike will not be dynoed, I don't care what it kind of power it makes, it makes me laugh that's enough
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fish_antlers
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The Truth is Out There
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posted June 29, 2008 11:43 AM
top...
let's talk more dynos...
so what are we accepting? SAE as the baseline?
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ricksgsxr
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posted June 30, 2008 01:23 PM
Are you bored today Fish? 
Good luck finding an answer that will fit for all.
Rick
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entropy
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posted June 30, 2008 06:49 PM
quote:
top...
let's talk more dynos...
so what are we accepting? SAE as the baseline?
Fish
IMO SAE vs STD is really a waste of time discussion when 95% of the dyno info posted is from Dynojet dynos.
Variation with Dynojet is so wide day to day and dyno to dyno that SAE vs STD correction is moot.
Dynojet info is real valuable when tuning a bike, but of small value when comparing one bike to another
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2000redrocket
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posted July 01, 2008 01:21 PM
i always go to the same dyno.
sofar in the spring i do all the dynoing and it is very repetable from year to year. and you here people bitch it is stingy along with people saying it is loose giving inflated numbers. all i can say is same dyno same week same weather +/- 5 degF i am up23 hp from the first stock dyno pull in 04.pipe, advancer. and ecu tweek.
i like the i am down 7 hp and i even filled up with a full tank of VP. lots of people try stuff that ends up lower. the race gas thing is a big think where i go . then you have the dyno queens that are kings of the dyno.a 07 gsxr 1000 blowing 203. this guy had lots to spend and lots of top end and i will never get him to race it. it is a bummer. it is fun watching the soap opera.
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k bryant
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posted July 01, 2008 06:44 PM
The basic issue is why some operators choose to what we refer to as "force" the numbers to read higher. SAE is, and always should be the "standard". I have asked several times previously for well known aftermarket companies to come on board and post their opinions as to what their logic is when posting data using STD settings. A common answer may be that their competitors post STD, so it may be the kiss of death for them to post 4% lower figures using SAE. I completely understand the logic of that. Does that make it right or wrong ? Perhaps not. But only if we all use the same basic settings (of which we have more than just STD or SAE as well).
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Megabyte
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posted July 01, 2008 07:02 PM
Should we also include whether the dyno operator is our friend, or just needs more business, geez
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k bryant
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posted July 01, 2008 07:04 PM
quote:
quote:
top...
let's talk more dynos...
so what are we accepting? SAE as the baseline?
Fish
IMO SAE vs STD is really a waste of time discussion when 95% of the dyno info posted is from Dynojet dynos.
Variation with Dynojet is so wide day to day and dyno to dyno that SAE vs STD correction is moot.
Dynojet info is really valuable when tuning a bike, but of small value when comparing one bike to another
Have to respecfully disagree. I have 1000's & 1000's & 1000's & etc... of runs with multiple Dynojet Dynos since the 80's to the present. Comparing same operators, same dyno, same basic parameters, it is a very accurate test base when comparing any bike and/or bikes together.
In our local area, there are many of us who compare numbers on the same model bike, and in many cases, the same "actual" bike (like for an OEM or Magazine). The numbers are reasonably similar. We talk to each other to see how our numbers all relate. The differences are really fairly minor and more importantly, reasonably explainable.
Besides the debate of comparing SAE & STD, I have found the largest difference is in drum mass calculations, tire pressure, and/or operator weight. Just as one example, lets say you don't have a brake attached. If you go out and install a brake and/or their optional brake, the drum mass needs to be recalculated. It's a simple software update, but it's surprising how many operators don't realize it. If not recalculated, your readings will be much lower.
I do believe though the best way to get accurate numbers, whether for tuning, testing, shoot-outs, whatever, is to test on the same day, same dyno, same operator, same baselines.
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