Question on Dyno?
Club Member
Joined: Jun 2007
Posts: 45,429
Likes: 2,898
From: Bedford UK
SAE is the Society of Automotive Engineers, who set standards for such things. DIN is something difficult in German, which is also widely used, but sets out to do similar things. Corrected means the readings are corrected to a standard set of atmospheric conditions, such as temperature pressure and humidity. Corrected figures can be directly compared wherever they are measured.
Uncorrected figures are those taken at the conditions on the day. So if it is cold and raining and at sea level, the figures measured will be significantly different than if the same bike was tested at high altitude on a very hot dry day. Corrected figures level those sort of things to a uniform level.
Smoothing takes out sharp fluctuations on the printed graph. Unsmoothed figures would like like an earth quake reading, smoothed figures are more easily read.
Hope that helps!
Uncorrected figures are those taken at the conditions on the day. So if it is cold and raining and at sea level, the figures measured will be significantly different than if the same bike was tested at high altitude on a very hot dry day. Corrected figures level those sort of things to a uniform level.
Smoothing takes out sharp fluctuations on the printed graph. Unsmoothed figures would like like an earth quake reading, smoothed figures are more easily read.
Hope that helps!
Last edited by grbrown; Jun 25, 2010 at 04:55 PM. Reason: Expanded.
SAE correction:
29.23 in/hg.
77* f
0 percent humidity
STD correction:
29.92 in/hg.
60* f
0 percent humidity
Higher air pressure and cooler air is is why the STD correction shows roughly 4 percent higher figures than SAE correction.
Here in the Pacific NW, we routinely have temps in the 50's, and the correction is downward from what the bike made at the rear wheel. If you're at a higher ambient temp, the numbers will be corrected upwards.
So no, the uncorrected number isn't always higher or lower. It's dependant on the atmospheric conditions compared to whichever protocol you're correcting to.
Either way, STD correction or SAE correction, it's a much better measurement than the "butt dyno" which is undoubtedly the most unreliable power measuring device on the planet. However, the gold standard for measuring performance gains is still a 1/4 mi dragstrip. A dyno won't tell you how fast a motor spools up or if the power is getting to the pavement.
29.23 in/hg.
77* f
0 percent humidity
STD correction:
29.92 in/hg.
60* f
0 percent humidity
Higher air pressure and cooler air is is why the STD correction shows roughly 4 percent higher figures than SAE correction.
Here in the Pacific NW, we routinely have temps in the 50's, and the correction is downward from what the bike made at the rear wheel. If you're at a higher ambient temp, the numbers will be corrected upwards.
So no, the uncorrected number isn't always higher or lower. It's dependant on the atmospheric conditions compared to whichever protocol you're correcting to.
Either way, STD correction or SAE correction, it's a much better measurement than the "butt dyno" which is undoubtedly the most unreliable power measuring device on the planet. However, the gold standard for measuring performance gains is still a 1/4 mi dragstrip. A dyno won't tell you how fast a motor spools up or if the power is getting to the pavement.
Last edited by Mike; Jun 25, 2010 at 05:31 PM.
Road Master
Joined: May 2009
Posts: 930
Likes: 4
From: Jacksonville, FL
Most dyno tuners use the sae standard, unless they are from the unethical crowd trying to show that they produce more "power" than other tuners. You have to look and pay attention to what the sheet says. If you browse the sticky on dyno numbers and look at the high figures, most of those sheets have std in the upper right hand corner.
Club Member
Joined: Jun 2007
Posts: 45,429
Likes: 2,898
From: Bedford UK
I would prefer corrected. Uncorrected may be higher or lower than corrected, depending on the conditions at the time of the measurements. If you live in Denver they will always be lower, just because of the altitude.
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