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Originally Posted by Max Well
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Originally Posted by Crashnbrn5
Wow this is great. but the 1/4 times on the larger engines seem way off, not even like a second, but much more.
My stock X3 35i does 13.8 sec at 99 mph in the 1/4 nearly every single time in 75 deg and over type of weather and fairly low elevation. On a colder night such as 30-40 deg with no wind my car can do it in 13.6-13.7 seconds at around 101 mph
Can you change some variables to reflect more realistic 1/4 times?
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Thanks, Crash. I'm not sure which of the Simulation Settings you are referencing which are way off at the 1/4 mile times. Remember only (A) [which is unladen, 0% grade, and 1 meter altitude] would be applicable to your situation. Simulations (B) and (C) indicate what performance might be expected to be like for +250 kg load, 3% grade, 2000 m altitude and +500 kg load, 6% grade, and 3000 m altitude, respectively, and they are consistent with what one would expect. Going up a mountain side with a significant grade and a heavy load would slow those times. (G01) reflects what we might can expect in our next generation X3s with their lower weight (here estimated to be 100 kg less) and improved Cd (from 0.35 to 0.32), which BMW was able to shave off in the X5s new style.
In (A), the numbers agree within a few tenths of a second across the board for the 1/4 mile times. And such agreement is also found in the 0-60 mph times, except for the 20i and 20d, in which the simulation appears to make them faster out of the blocks by at least 0.5 seconds c/w BMW's numbers. I have spent quite a bit of time looking at that and can't figure why the smaller engines aren't being modeled as accurately early in the curves as all of the larger engines. As mentioned before, though, there are a lot of complex equations which go into this, and for continuity I did not wish to try to change things up for one engine vs another. In a comparison analysis, which was the intent of this project, I wanted to make sure all equations and coefficients remained the same across the board.
I'm attaching here a more 'zoomed-in' look at the 60 mph and 1/4 mile times here, with dashed lines highlighting the X3-M, X3-40i, and X3-35d/35i (which nearly superimpose in this construct) for clarity: |
Okay I see now on this chart it looks more accurate. I do remember reading through the tables not the graphs where I saw that the times are off. But when you draw the dashed line vertically on the graph you can see much easier the simulated numbers