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      02-13-2018, 06:45 PM   #5
esquire
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Drives: 2011 Dakar Yellow M3, 2018 M5
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Quote:
Originally Posted by GNALUZU View Post
Not to knock the new M5, because I am becoming more and more interested in it... the method used to get the 2.8 second results are not exactly the most repeatable.



Basically, doing a brake stand before launch. C&D says that after a few runs it dials back the launch RPM, but I wonder how many times until the car goes in to limp mode.

Well, the launch control is technically very "repeatable." Like C&D said: "A perfect launch is as easy as holding the brake and the accelerator while stopped." So getting C&D's exact results should be no problem.

But what you're noting is not an issue of repeatability. But rather a programming issue: after a few runs, the ecu intentionally drops the launch control RPMs from 3000 to 2500, resulting in less traction on launch and going a few tenths slower to 60. Dropping the RPMs down to 2500 is done probably to protect the car out of an abundance of caution, and I'm willing to bet (prematurely) that its something that can be coded out later. Realistically speaking though, how many times are you going to be dropping the hammer on your car on a full blown launch control? I doubt more than once or twice a day.

I'm sure they drop the launch RPMS down to 2500 precisely to avoid going to limp mode, so I don't think you'll have concerns there.

The simple fact that we're talking about a stock sedan in the 2.x territory, and 10 second territory for the quarter mile is crazy.

- esquire
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