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  #11  
Old 10-08-2009, 04:08 PM
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Those are some crazy numbers. =D The article says they achieved 5.1 seconds 0-60 without launch control though?

And what is rollout?
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  #12  
Old 10-08-2009, 04:13 PM
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"roll out" is basically the distance your front tires must travel to "exit" the
starting line lights, and initiate your timed run; also used to determine
reaction time.
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  #13  
Old 10-08-2009, 07:15 PM
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Originally Posted by ///MB View Post
Those are some crazy numbers. =D The article says they achieved 5.1 seconds 0-60 without launch control though?

And what is rollout?
5.1 was their initial press the gas and go from what I recall.

It definitely requires some torque braking.

Rollout - read this from Edmunds:

A Few Words About Rollout
The term "rollout" might not be familiar, but it comes from the drag strip. The arrangement of the timing beams for drag racing can be confusing, primarily because the 7-inch separation between the "pre-stage" and "stage" beams is not the source of rollout. The pre-stage beam, which has no effect on timing, is only there to help drivers creep up to the starting position. Rollout comes from the 1-foot separation (11.5 inches, actually) between the point where the leading edge of a front tire "rolls in" to the final staging beam — triggering the countdown to the green light that starts the race — and the point where the trailing edge of that tire "rolls out" of that same beam, the triggering event that starts the clock. A driver skilled at "shallow staging" can therefore get almost a free foot of untimed acceleration before the clock officially starts, effectively achieving a rolling-start velocity of 3-5 mph and shaving the 0.3 second it typically takes to cover that distance off his elapsed time (ET) in the process.

We believe the use of rollout for quarter-mile timed runs is appropriate, as this test is designed to represent an optimum drag strip run that a car owner can replicate at a drag strip. In the spirit of consistency, we also follow NHRA practice when calculating quarter-mile trap speed at the end of the run. So we publish the average speed over the final 66 feet of the quarter-mile run, even though our VBOX can tell us the instantaneous speed at the end of the 1,320-foot course, which is usually faster.

On the other hand, the use of rollout with 0-60 times is inappropriate in our view. For one, 0-60-mph acceleration is not a drag-racing convention. More important, it's called ZERO to 60 mph, not 3 or 4 mph to 60 mph, which is what you get when you apply rollout. While it is tempting to use rollout in order to make 0-60 acceleration look more impressive by 0.3 second, thereby hyping both the car's performance and the apparent skill of the test driver, we think it's cheating.

Nevertheless, some car magazines and some automobile manufacturers use rollout anyway — and fail to tell their customers. We've decided against this practice. We publish real 0-60 times instead. But in order to illuminate this issue and ensure we do justice to every car's real performance, we've begun publishing a clearly marked "with rollout" 0-60 time alongside the primary no-rollout 0-60 time so readers can see the effects of this bogus practice.
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  #14  
Old 10-08-2009, 08:42 PM
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  #15  
Old 10-09-2009, 12:52 AM
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Thanks, so rollout is basically after the car is already rolling.

So, it looks like launch control is basically just brake torquing but a little fancier? lol. I'm pretty sure that's not very good for the torque converter. So realistically the 0-60 time is more like 5.1 seconds. For example, if I'm at a red light and I wanna get in front of the guy next to me, I'm not gonna sit there torque braking while waiting for the light to turn green.
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  #16  
Old 10-09-2009, 07:36 AM
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So realistically the 0-60 time is more like 5.1 seconds. For example, if I'm at a red light and I wanna get in front of the guy next to me, I'm not gonna sit there torque braking while waiting for the light to turn green.
Yes, but the times you see qouted by manufacturers and magazines for all other cars are either launched at crazy revs or very cautious feeding of power in the case of a very powerful RWD car. So really, you could easily add a second or even more to every other car too...
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  #17  
Old 10-09-2009, 08:03 AM
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Quote:
Originally Posted by ///MB View Post
Thanks, so rollout is basically after the car is already rolling.

So, it looks like launch control is basically just brake torquing but a little fancier? lol. I'm pretty sure that's not very good for the torque converter. So realistically the 0-60 time is more like 5.1 seconds. For example, if I'm at a red light and I wanna get in front of the guy next to me, I'm not gonna sit there torque braking while waiting for the light to turn green.
Rollout gives the car an 11.5" start. Some magazines and many manufacturers use rollout in their reported 0-60 times. Some do not.

5.1 seconds was their initial shakedown run. Not the 'final' non-LC number.

Anyone with an automatic (/// or Buick) torque brake to some extent if they are trying to maximize takeoff. It's tantamount to revving your engine higher with a manual....Full launch control 'at a light', probably not.

It might be helpful if you read the article.
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  #18  
Old 10-09-2009, 02:32 PM
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.....So realistically the 0-60 time is more like 5.1 seconds. For example, if I'm at a red light and I wanna get in front of the guy next to me, I'm not gonna sit there torque braking while waiting for the light to turn green.
I don't know if I would draw that conclusion. As HIRISC said, 5.1 seconds was just a 'feeling-out' run by this one team. But there are a lot of non-launch numbers coming out now, from other publications like Car and Driver and others, both with the X6///M and X5///M. C&D got 4.3 seconds on a pre-production X6///M that did not have launch control. If you then translate that to BMW's official stats that put both the X6///M and X5///M as "equals" (with both listed at 4.5 seconds by BMW) I would think the X5///M should get within 0.1-0.2 seconds of whatever numbers are obtained for its' X6 cousin. So based on what we're seeing in print thus far, if you just gun it from a traffic light without LC or even torque-braking, you should still be below 5 seconds on a 0-to-60 sprint.
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  #19  
Old 10-10-2009, 12:13 PM
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  #20  
Old 10-10-2009, 01:39 PM
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EVO review of X6 M
BMW X6M | Car review | evo
Must be an UK thing - consistently pessimistic.

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