ECMTuning - wiki

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<h1>HP/Torque estimates</h1> <div class="level1"> <p> Martin Check provided the horsepower and torque calculators included with DSMLink. These routines were derived from work done by John Peckham and Anil Rao on a standalone excel spreadsheet type of thing. Martin took those calculations and ported them into DSMLink. Many thanks go to Martin, John, and Anil for this work. The routines are surprisingly accurate and provide a very useful feature in DSMLink. However, to use them effectively, you do need to keep some design constraints in mind. </p> <p> Getting usable numbers from the HP (torque) estimates in DSMLink is all about running controlled tests. A flat, smooth stretch of road with a pull off at one end is what I use. In my case, there's a "round about" at the other end, which makes it even better. I start a log, cruise a few seconds to the flat stretch, do a solid 3rd gear pull, turn around at the round about and do a 3rd gear pull in the other direction in the same stretch. Then pull off at the pull off area (happens to be a park-n-ride) and review the data. Pop the hood, let the car cool down significantly, make a few changes, and go retest. </p> <p> Whether you get accurate numbers that you can compare directly to dyno figures isn't all that important. As long as you're getting repeatable numbers, you can do reasonable before/after type comparisons. Although, in my particular case, I do see almost exactly the same values on the dyno as I see with the estimates on this flat stretch of road. </p> </div> <h1>Algorithm</h1> <div class="level1"> <p> The calculation of HP/torque is done by watching RPM acceleration and factoring in drag based on wheel speed. The routine also uses information provided by the user on wheel size and drivetrain loss. You configure those values by right clicking on either HP or Torque in the graph legend and then selecting "Props". </p> </div> <h1>Examples</h1> <div class="level1"> <p> The following was posted by one of our users as an example of what he saw as a comparison between the HP/Torque estimates in DSMLink and an actual dyno pull. Not too shabby. </p> <p> <b>Click to enlarge</b> <a href="/wiki/lib/exe/detail.php?id=hptorque&media=dynosnap2yr1.jpg" class="media" title="dynosnap2yr1.jpg"><img src="/wiki/lib/exe/fetch.php?w=341&h=246&tok=ea1843&media=dynosnap2yr1.jpg" class="media" title="Dyno comparison" alt="Dyno comparison" width="341" height="246" /></a> </p> </div>