Quote:
Originally Posted by jamoka3
Max Well over at the X3 forum has developed an acceleration model for the X3 and several other BMW model types. He has dedicated a lot of his time and has been plotting drag times vs the simulation for actual dragway slips.
He has offered to run my 1/4 times and some 0-60 times in real world numbers...He should be completed soon and post a graph to help solve some more questions, we may have about RT, Trap speed and 60' information.
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Greetings, all,
Jamoka3 joined a number of other forum members at Island Dragway 21 Aug 2015 and ROBNYC shared a few of his slips with me. As the folks on the X3 forum know, I have no background in Physics, engineering, or automobiles at all, but have always been fascinated with the performance of our BMWs over the years. Last year, after reading about how the new series X5s actually had better highway mileage than our smaller and lighter X3s I researched the mechanisms behind such.
I initially analyzed the HP required to maintain constant speed across the range of all of BMW’s line. It quickly became clear how important Cd (coefficient of drag) and frontal surface area are in allowing vehicles to slip through the air. If anyone is interested in that initial project, it can be found at: ‘Horsepower and Speed – the graph’ [
http://x3.xbimmers.com/forums/showthread.php?t=1004702 ]
As we in the X3 realm are looking forward to the new G01 models to be released next year (to also include 40i and true M variants), I began wondering how the aerodynamic and HP changes they are planning might affect the X3’s performance, but I couldn’t find any information online.
After a fair amount of research I found a Master’s Thesis from 2002 by Matthew Snare in which he and his Professors developed a series of equations to allow a ‘Dynamics Model for Predicting Maximum Acceleration Rates of Passenger Cars’. So I developed Excel spreadsheets using their equations to allow one to change parameters of the equations unique to each model type. Although my initial studies were mainly on the X3, it seemed reasonable the simulation’s construct should work for any vehicle (as Matthew Snare validated with 13 different vehicles in his initial research), as long as one has the correct data such as Cd, frontal surface area, weight, HP, etc., ... If one is interested in the particulars the main thread can be found at: ‘!X3 Acceleration Files – Master List!’ [
http://x3.xbimmers.com/forums/showthread.php?t=1149189 ] .
With that as a brief background, jamoka3 asked in a PM if there was a way to look at his 0-60 mph times, as Island’s drag slips don’t provide such (only the eighth and qtr mile times provide the speed). By superimposing the Distance and the Speed charts one can at least get a rough idea if one’s curves can be extrapolated by following the simulation’s curve as a rough guide. I’m attaching the summation chart here at jamoka3’s request, as well as a chart summarizing his drag slip times. As can be seen, his tuned runs closely approximate the simulation’s curve, so it would seem reasonable to suggest he ran about 0.5 sec faster on the 0-60 mph time, or around 5.5 sec, c/w the ‘stock’ time of roughly 6.0 sec.
Apologies for the length of the post, but to just place a chart here without any background seemed a disservice, and I hope it provides some assistance to jamoka3’s question. For more focused 1/8th mile and ¼ mile views of his ‘stock’ and ‘tuned’ runs, those can be found in the Master List thread.