F26 X4 xDr 1/4 Mile Thread

vendredi 25 septembre 2015

Quote:

Originally Posted by X4guy (Post 18625866)

Thanks for the work Max, much appreciated.

Quote:

Originally Posted by Max Well (Post 18629837)

Thank you for the kind words, X4guy - I'm happy to be able to share data on these amazing BMWs. If you think any of the X4 folks would be interested in dedicated curves for your line I'd be pleased to prepare those as well for you. :)

Quote:

Originally Posted by X4guy (Post 18631743)

That would be most welcome if it's not too much trouble.

Having evaluated the performance of the F26 X4 in threads 'HP and Speed - the graph' [ http://ift.tt/1QymQap ] and '!X3 Acceleration Files - Master List!' [ http://ift.tt/1jatgSF ], it seemed reasonable to begin a F26 X4 1/4 Mile Thread much as our colleagues on the F30 forum did back in Oct 2012. In three years it has garnered roughly 33K views, and although that model may attract more folks interested in modifications and maximizing performance of their vehicles, it seems there are segments of the X3 and X4 realms which share similar interests. This will allow for a reference base for performance data provided by formal drag slips.

The following templates are being attached: Chart Worksheet for making notes at the track; overview graph of the 0-16 sec plot of the 28i performance curves ranging from stock HP +/- 50 HP in 10 HP increments (including the boxes showing the zoomed regions); graph of 8-10 sec performance curves which captures the 660 ft (1/8 mile) point; graph of 13-15 sec performance curves which captures 1320 ft (1/4 mile) point; and the 60 mph interval which can provide an extrapolation of one's 0-60 mph time once the reference curve from the 1/8 and 1/4 mile times has been established. These should make it easy to plot in real-time while at the track and in-between runs. Note these curves have been run at sea level for continuity. References suggest up to 1200 feet altitude doesn’t have a major effect on the performance of turbocharged engines, which may be why correction factors below this altitude aren’t common. http://ift.tt/1QymS1P

As an example of how the worksheet can be used, I included a summary of ROBNYC's, mge92's, and Crashnbrn5's F25 X3 runs at Island Dragway in the ‘F25 X3 ¼ Mile Thread’ I wrote 2 days ago [ http://ift.tt/1gUNnm6 ]. Note it also provided the 'split times', which allow a more detailed look at performance as it removes rollout differences, (a summary of their usefulness can be found at http://ift.tt/1jatetT ). I had Excel highlight the fastest runs for each person's specific interval to make it easier to gauge the effects of tuning adjustments. If actual drag slips can be posted as jpegs, then periodic summary tables can be made. Also, if feasible, if tunes can be disabled briefly to allow stock run data to be obtained on the days modified runs are to be made, that should enable a reasonable reference with which to compare differences due to actual performance changes vs the host of other variables which can change between days and influence the end result (temp, barometric pressure, altitude, weight, tires, wind, track ...).

As mentioned in the other threads, these equations and graphs are simply meant to provide those of us without dynos and high-end software to be able to at least put some science behind the performance of our vehicles. Thanks for reading, and if interest is there, curves for the 35i can also be produced.

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