[Max Well]

Have added GT500R's 14 Apr 2019 runs into spreadsheet format as posted in his thread at https://x3.xbimmers.com/forums/showthread.php?t=1604114 .

I was unable to read the datasheet in which the lowest time was recorded, but can add that run in another column if those details become clear. Looking at the Sim's graph shown in an earlier post, it seems the HP estimate is now closer to roughly 450. Would be interested to know if Mission Performance has dyno HP figures for the Stage II ECU and Stage I TCU modifications on the G01 to see how close the Sim is estimating that.

[GT500R]

Fastest run

1.782 60'
5.049 330'
7.770 1/8
90.38 mph
10.119 1000'
12.101 @ 113.81 1/4

[Max Well]

Originally Posted by GT500R

Fastest run...

Thanks GT500R - chart updated:

[iManu]

New 1/4 mile times, we were 2 in the car and half tank of gas!
12.11@113.43!

[GT500R]

If this is a dragy time thread should I post the 11.9 I ran and 9.9 100-200?

[Max Well]

Originally Posted by GT500R

If this is a dragy time thread should I post the 11.9 I ran and 9.9 100-200?

The main reason I started this thread was to provide a centralized resource for all data regarding Qtr Mile times in the G01 series. The idea came from following the six-year-old 3ers thread of similar name which has close to 190K views and is a 'Sticky' on that Forum: https://f30.bimmerpost.com/forums/sh...d.php?t=752814

As time goes by threads get buried deep in a Forum and it becomes next to impossible (or at least very cumbersome) to continually search for old threads when trying to find previous runs to compare times, especially when you can't remember the thread's OP, other Posters' names, or title.

So feel free to share Dragy times here as well as it'll spark more interest in the hobby, but I'm only going to enter confirmed Drag Slips into the Spreadsheet format where one can view split times and other notes pertaining to the individual runs. If we start getting enough confirmed entries with all info available (including DA, temp, etc.) I've been thinking about starting a 'Leaderboard' of sorts, which I could keep updating on the first page, but that would really only be necessary when the thread grows to a number of pages, as it's easy now to scroll down the limited number of posts it currently contains. Right now you are Number 1 in that format.

[wannax3?]

Just for my entertainment, I've developed a numerical integration time history simulation of the X3 M40i acceleration. This is done as an Excel program, with successive lines for each time cut. Factors included are weight, aero drag, rolling friction drag, tire rolling radius, transmission and final drive gearing and the published straight line segments for the engine torque curve, which is flat at 365 ft-lb from 1520 to 4800 rpm.

As the simulation progresses, at each time cut the known velocity determines which gear is used, which then determines the engine RPM, which then determines the engine torque, which ends up as forward thrust at the ground. The gear is shifted up at the input max RPM. At each point the aero drag is subtracted from the tire thrust, and the net force accelerates the vehicle, using F = ma, solved for a.

This is then numerically integrated to obtain velocity and distance to proceed with the simulation, which is run to 60 seconds. Other parameters in the simulation include initial and shift RPM (3000 & 6500), car weight of 4482 pounds. The numerical integration time interval is 0.05 seconds.

As noted by the OP, the major unknowns are the tire-ground interface friction and the powertrain energy losses. These are both simplified to a constant tire-ground friction and a constant factor multiplying the torque values uniformly at all RPMs. I've established values for these parameters to match acceleration data published by a Car & Driver test report. Tire ground friction = 0.80 and powertrain loss factor = 0.85 yield good correlation with the test values, shown in the attached pdf file.

To match the 1/4 mile times of around 12.4 seconds shown in above posts (average of 8 values) for modified engines, the torque curve needs to be increased by a factor of 1.25. That implies peak horsepower at the engine would be 1.25*355 = 444. Corresponding 1/4 mile speed would be 114.3 in the sim vs 110.6 from the actual 1/4 mile runs. The simulation projects a top speed of 183 for the 444 HP engine.

Max

[Max Well]

First, apologies to 'wannax3?' for just now seeing his post back on 23 Apr - contribution much appreciated.

Have added iManu's 2 May 2019 runs to the Montreal (Seaz, emmanuel.yoo, and iManu) group's spreadsheet, which he shared in his thread at: https://x3.xbimmers.com/forums/showthread.php?t=1610299 . As Icar has reported elevation of 249', and the Dragy indicated 75' (and iManu mentioned that was on a closed circuit not at the drag strip), I looked up Montreal's weather data on the site mentioned in post 18 to arrive at an estimated DA. If it ever works out for two of you to race the same night it would make for a good comparison of your mods with direct split time data.