Navigation Menu
Delta dyno testing
Wottle She Do? And the transition from Inertial dyno to datalogger-derived power curves.
Much more to come on this subject. In the meantime, here's one graph for my KTM-
1) The "happy" HP figures off a local dyno
2) vs my best estimate of what it should read in "the dynojet world"
3) the power curve calculated by the actual acceleration, mass, and drag HP measured.
On the chart below, the KTM showed 172 RWHP at 8500 RPM, and almost 107 ft-lbs. (blue curve)
Now, while this was a boast-worthy result, and would have made great fodder for endless bickering on internet forums or convenience-store parking lots, I knew that based upon seeing many dyno charts for this bike, with these mods, 172 was too much. Definitely, I had to toss aside this lovely big number. My best guess put it around 163 "Dynojet" hp at 8500, based on similar bikes. (green curve)
Using the datalogger, I generated the pink curve - for whatever reason my engine held on better at high revs or maybe I had a gust of tailwind on that test ( always a risk) but the REAL HP delivered was about 145 at 8500 RPM. (Again- This is a chart from my KTM!!)
So, in this case, the actual RWHP was about 89% of Dynojet HP at 8500... or, multiply by 12.4%
Here's an interesting web page by the Factory Pro dyno people, on "real" RWHP:
http://www.factorypro.com/dyno/true1.html
The correction factor they mention is 1.15 to 1.22x to convert to Dynojet HP.
The "real" HP figures we're calculating off the logger are definitely in the ballpark relative to Factory Pro figures. I'm pretty optimistic that the "true" rear wheel figures I'm generating/ working with would be backed up by a Factory Pro dyno.
Superflow technicians said this was the same process, and mentioned a 15% multiplier to get back to "dynojet" figures. On the Superflow at Daytona, operated by Superflow technicians, the Delta made 132 HP in 2004. (about 150 DJ RWHP) And it made more by 2010, but that's a story for another page.
So - going forwards - using the datalogger I will be trying to work with "true" rear wheel HP figures. I'll be generating "true" thrust vs weight plots - which should allow us to make accurate predictions of real world performance. I also have software (of course) that can predict real world performance, so we'll see how well it does vs the actual data.
I can be contacted at rg500delta@mac.com
