[bimmerhw]

Hi guys

I just did a couple of test runs on my f30 340i(2016), all stock options.
Without launch control.
on a normal highway, clear and dry condition.

Tire is not new, but in good condition.
tested with both Sports/Sports+,
The best shot I got is just 5.47s for 0-100km/h. (5.3s/0-60)

btw, I am using Torque pro/ODB Bluetooth for the tests.

Is that normal? How can I be closer to the official claimed 4.6s?
5.4s to 4.6s sounds like a huge gap, wondering what could be the reasons?
Anything I can do to improve it? (still with stock options)

[Skyhigh]

Ok, a couple of things here:

1. From what it sounds, you are not even measuring accurately enough. You need a Dragy or P-Gear for a measurement which is accurate enough to compare to others or to official figures! Anything else is just a random guess! Trust me - I had my hopes on BMW's own Laptimer app, which uses car live data, but even that turned out to be far from the truth.

2. The above aside, 5,47 does sound a bit slow. But again - your figure is rather a guess, not a measurement.

3. Why not use Launch Control....!? That's its sole purpose....

4. Don't know where you read 4,6 as an official 0-100 figure, but that's quite incorrect. Without xDrive and MPPSK, the official figure for your vehicle is 5,1 s. 0-100.

5. Even with MPPSK, without xDrive you will struggle to keep it consistently under 5.

So realistically and with the right equipment you should be able to do around 5-5,2 with LC. The time depends heavily on your car equipment configuration as well (sunroof, tow bar, etc., etc.). If your car is rather basic, you may beat the official figure.

[bimmerhw]

Originally Posted by Skyhigh

Ok, a couple of things here:

1. From what it sounds, you are not even measuring accurately enough. You need a Dragy or P-Gear for a measurement which is accurate enough to compare to others or to official figures! Anything else is just a random guess! Trust me - I had my hopes on BMW's own Laptimer app, which uses car live data, but even that turned out to be far from the truth.

2. The above aside, 5,47 does sound a bit slow. But again - your figure is rather a guess, not a measurement.

3. Why not use Launch Control....!? That's its sole purpose....

4. Don't know where you read 4,6 as an official 0-100 figure, but that's quite incorrect. Without xDrive and MPPSK, the official figure for your vehicle is 5,1 s. 0-100.

5. Even with MPPSK, without xDrive you will struggle to keep it consistently under 5.

So realistically and with the right equipment you should be able to do around 5-5,2 with LC. The time depends heavily on your car equipment configuration as well (sunroof, tow bar, etc., etc.). If your car is rather basic, you may beat the official figure.

Thanks for the reply.
It does make sense in this case if considering the measure deviation and the offical is 5s but 4.6s.
I never ran with launch control, so make sense.

[Skyhigh]

.... Therefore if you really want to know - buy a dragy / p-gear and measure again, preferably with LC. Some people achieve better results without LC, using other techniques, but to compare to official figures - I'd recommend starting off with LC and letting it do its thing.

You should be able to do 5-5,2 s depending on your configuration and environment.

[bimmerhw]

Originally Posted by Skyhigh

.... Therefore if you really want to know - buy a dragy / p-gear and measure again, preferably with LC. Some people achieve better results without LC, using other techniques, but to compare to official figures - I'd recommend starting off with LC and letting it do its thing.

You should be able to do 5-5,2 s depending on your configuration and environment.

I never successfully got the LC flag. so mostly just stand still and then push throttle fully.
Normally would LC be 0.1~0.2s faster than without LC if no special techs applied?

[Skyhigh]

That's hard to tell. Some people achieve better results without LC, it all depends on the technique. But LC is a more "defined" and safe way to lunch. I would think one gets more consistent results with LC, even if not necessarily the best results.

[Skyhigh]

P.s. so you were not holding the brake the build-up boost when you did it!? That would explain the poor time!

Try again to trigger LC. Engine must be warm for it to work and you need to be in Sport+.
Again - it may not give you the absolute best time, but it is a controlled and “calibrated” (and self-calibrating) approach, which is also safer for your car.

[thejeremyman9]

Originally Posted by Skyhigh

P.s. so you were not holding the brake the build-up boost when you did it!? That would explain the poor time!

Try again to trigger LC. Engine must be warm for it to work and you need to be in Sport+.
Again - it may not give you the absolute best time, but it is a controlled and “calibrated” (and self-calibrating) approach, which is also safer for your car.

LC safer? LC is generally much harder on drivetrain than just flooring it from a stop or doing a little footbraking at part throttle. BMW specifically has disclaimers about overusing LC

[Skyhigh]

Originally Posted by thejeremyman9

LC safer? LC is generally much harder on drivetrain than just flooring it from a stop or doing a little footbraking at part throttle. BMW specifically has disclaimers about overusing LC

You are wrong.
Where/what are the disclaimers then? The only disclaimer is that launching your car puts it under more stress than not lunching! That's kind of a given....
But what is LC mode for, if not for a controlled launch?

Launch Control limits the RPMs, monitors various parameters and adjusts in accordance. It will for example not activate if your engine is not warm enough or gearbox too hot from last launch - these are just two examples of the protective mechanisms it applies.

If you are to launch your car, LC is the safest way to do it, but not necessarily the fastest, as even BMW admit in the manual.
Clearly not launching it at all is even safer.

[thejeremyman9]

Originally Posted by Skyhigh

You are wrong.
Where/what are the disclaimers then? The only disclaimer is that launching your car puts it under more stress than not lunching! That's kind of a given....
But what is LC mode for, if not for a controlled launch?

Launch Control limits the RPMs, monitors various parameters and adjusts in accordance. It will for example not activate if your engine is not warm enough or gearbox too hot from last launch - these are just two examples of the protective mechanisms it applies.

If you are to launch your car, LC is the safest way to do it, but not necessarily the fastest, as even BMW admit in the manual.
Clearly not launching it at all is even safer.

Nice try, but I'm not wrong. The disclaimers are in the owner's manual lol... The owner's manual specifically says "The use of Launch Control causes premature component wear..." Here's one post about it with a screenshot, you can check your own owners manual. https://g80.bimmerpost.com/forums/sh....php?t=1924574

This is also discussed by XHP: "What the ZF 8-Speed Auto actually does in Launch Mode is to engage a different shift mode, which is only active when the aforementioned procedure is carried out. The characteristic of this mode can be described as "i-don't-care-about-my-clutches-mode". Yes, LC mode makes your transmission wear. " https://rbttuning.atlassian.net/wiki...LAUNCH+CONTROL

I don't disagree that LC is a way to perform consistent launches. But it is 100% true that LC is a more aggressive (read - causes more wear) than other ways of launching "softer" even if these "softer" launches may sacrifice tenths of a second. As mentioned above, is not only the launch itself, its the shift mode in the trans after you launch that contributes to said wear as well, which is avoided by not engaging LC.

[Skyhigh]

See above - I posted the user manual! And yes - you are reading it completely wrongly!

The disclaimer tells you that if you are launching your car, you induce extra wear (shockingly! who could imagine...). Not that using LC as a mode adds extra wear in comparison to if you do an uncontrolled launch with 5000 rpm and cold engine or hot gearbox where you would get less wear just because you are not using LC!!!

Read the name of the mode please and think about it - Launch CONTROL

Control is key here!! What you do without it is an UNcontrolled launch! It may be less aggressive if you do it softly (but then why launch at all?), but it can be significantly more aggressive, if you do it to measure 0-100!

Why would they design a mode specifically for launch otherwise and also tell you it may not give you the best results? Think about it... and its name! It is a mode designed by BMW to give you a controlled launch and still retain the factory warranty! That actually tells it all.

[thejeremyman9]

Originally Posted by Skyhigh

The disclaimer tells you that if you are launching your car, you induce extra wear (shockingly! who could imagine...). Not that using LC as a mode adds extra wear in comparison to if you do an uncontrolled launch with 5000 rpm and cold engine or hot gearbox where you would get less wear just because you are not using LC!!!

Your counterargument doesnt make any sense to try and justify why LC is "safer". We are talking about a situation of using LC vs not using LC, all else being equal (i.e., obviously warm up the engine, monitor your temps, etc). In that situation, LC irrefutably puts more wear and tear on the transmission (and drivetrain more generally, but specifically trans). That's all i am saying, which is backed by the manual, XHP, etc.

I am not saying anything about how controlled that launch is and whether or not it achieves the best times etc. Just because BMW (and other OEMs) added the mode to the car stock doesnt mean what i mentioned above isnt true. There's a reason there are limits to using it and the dealer can check the launch count.

People can choose to use it or not depending on their risk tolerance and use case for the car. I am merely presenting the information. If you want to continue believing that LC doesnt cause [more] wear than launch away.

[Skyhigh]

You basically insist that a controlled launch designed by the car OEM to be used by any driver, within the warranty period of the vehicle, is more harmful than a random, uncontrolled one performed by John the farmer going after 1 sec 0-100 …

I’ll let you believe that, apparently that makes sense to you…. 😉

Let’s agree to disagree. I will keep claiming the obvious and logical.

At least we both agree about one thing - don’t launch at all if worried about wear. (Which is what the manual says too )

[thejeremyman9]

Originally Posted by Skyhigh

You basically insist that a controlled launch designed by the car OEM to be used by any driver, within the warranty period of the vehicle, is more harmful than a random, uncontrolled one performed by John the farmer going after 1 sec 0-100 …

I’ll let you believe that, apparently that makes sense to you…. 😉

Let’s agree to disagree. I will keep claiming the obvious and logical.

At least we both agree about one thing - don’t launch at all if worried about wear. (Which is what the manual says too )

I am only insisting what is clearly documented: Using LC causes premature component wear - more wear than just accelerating from a dead stop (i.e., a "launch") without lunch control with all else being equal (temperatures, conditions, etc). I'm not sure how that isn't obvious and logical, particularly given what we know about launch control not only affecting the launch but changing the shift mode during the subsequent acceleration. Using launch control by definition puts the car into a mode that causes more wear, so how can you possibly say that using it doesn't do so compared to not using it? Again we are talking about all else being equal, not "John the farmer" going out with ice cold engine oil or an overheated transmission and trying to do dig runs. We arent talking about user error.

We are talking about LC by definition putting the car into a mode that causes more wear than not using it when accelerating. That's it. Anything else about how someone actually accelerates or "launches" their car is speculative and depends on the specific person and conditions at the time.

[Skyhigh]

Originally Posted by thejeremyman9

I am only insisting what is clearly documented: Using LC causes premature component wear - more wear than just accelerating from a dead stop (i.e., a "launch") without lunch control

What is the name of this thread? Does this look like "just accelerating"? The whole thread is dedicated to a 0-100 measurement! Hence a HARD launch no matter how you go about it.

with all else being equal (temperatures, conditions, etc).

Yes - if you manually manage to mimic all properties of a an automatic LC, including RPM, boost, preventive features, etc. - you are correct. How likely is that do you think, whilst chasing 0-100 times??

Mind the topic! It is relevant! We are not talking about driving off a red light here! We are talking exclusively about 0-100 best time! bake it, boil it, smoke it - it will always be a hard launch! A controlled hard launch is always less harmful (but not necessarily as fast) than an uncontrolled hard launch! Which is probably why the feature is called "Launch CONTROL" and is provided by BMW, within factory warranty.

How is this not logical and obvious, in the context of a HARD launch, I'll never know. Back to my original claim - Launch Control is the safest way to chase best 0-100 times!

Clearly I do not claim LC is safer for driving off your driveway to work than simply accelerating as a normal human being! But the thread is not about that, is it?

[thejeremyman9]

Originally Posted by Skyhigh

What is the name of this thread? Does this look like "just accelerating"? The whole thread is dedicated to a 0-100 measurement! Hence a HARD launch no matter how you go about it.


Yes - if you manually manage to mimic all properties of a an automatic LC, including RPM, boost, preventive features, etc. - you are correct. How likely is that do you think, whilst chasing 0-100 times??

Mind the topic! It is relevant! We are not talking about driving off a red light here! We are talking exclusively about 0-100 best time! bake it, boil it, smoke it - it will always be a hard launch! A controlled hard launch is always less harmful (but not necessarily as fast) than an uncontrolled hard launch! Which is probably why the feature is called "Launch CONTROL" and is provided by BMW, within factory warranty.

How is this not logical and obvious, in the context of a HARD launch, I'll never know. Back to my original claim - Launch Control is the safest way to chase best 0-100 times!

Clearly I do not claim LC is safer for driving off your driveway to work than simply accelerating as a normal human being! But the thread is not about that, is it?

OP specifically said he didnt use launch control actually. "HARD" launch does not equal fast launch - both in your posts above and in the LC documentation you posted. Hence LC can be not only a bad idea from a wear perspective but also from a acceleration speed perspective. This is particularly true for RWD cars and there are tons of threads specifically focused on how to achieve the best launch, and for RWD it's often not using LC (especially when traction-limited). So you can accelerate faster and with less wear without using LC - while still launching "HARD" to use your term. That's probably a key takeaway - we know that LC puts the car into a mode that increases wear, and we also know that LC may not provide the fastest acceleration. So sure, experiment with LC if you want but just keep all of these things in mind. I'm obviously not comparing LC to casual acceleration. I'm talking about LC vs non-LC "launches".

I suppose we just fundamentally disagree on the underlined part above since what you said about it being less harmful is inconsistent with all documentation on what LC actually does and how it affects the car during the launch and acceleration. If you truly believe this true than every single time you want to launch "HARD" you should be using LC, which i guess you do? It's called launch control because it controls the launch. It has nothing to do with controlling [read: reducing] wear.

[Also not clear what HARD means. Since HARD doesn't seem to correlate to either wear or acceleration speed in your explanation.]

Anyways, just providing some information on LC for OP's benefit in the context of the discussion around the 0-100km times (both from a wear perspective and now somewhat an actual acceleration speed perspective). OP and others can choose to do whatever they want. So yes, this is definitely relevant.

[Skyhigh]

Ok.
Your view is noted.
Agree to disagree. And if you dig a bit deeper in the documentation and statements BMW has made about LC through the years, you will realise that the mode is there for a reason. (If it ain’t fastest possible acceleration, what could it possibly be...)

What is BMW Launch Control?
In the words of BMW — “Launch Control enables optimum acceleration on surfaces with good traction.” In simpler terms, Launch Control is an electronic driver assistance feature that turns your standing start into…well, a launch, greatly boosting the speed at which you accelerate from a stop.
Using a computer program and the innovation of an electronic accelerator, Launch Control delivers safe and optimized acceleration to drivers. It was first designed with racers in mind, but the technology has been installed in both street- and track-specification BMW cars. The system accelerates your car smoothly and quickly, without causing the drive wheels to spin.
The system is also designed to take other factors into account and prevent over-revving, as well as the potential clutch and gearbox problems.

I rest my case.

[bimmerhw]

Originally Posted by Skyhigh

P.s. so you were not holding the brake the build-up boost when you did it!? That would explain the poor time!

Try again to trigger LC. Engine must be warm for it to work and you need to be in Sport+.
Again - it may not give you the absolute best time, but it is a controlled and “calibrated” (and self-calibrating) approach, which is also safer for your car.

I did hold the brake while trying LC, maybe I didn't hold it completely is the reason I failed. Later on with my 5.47s test runs, I didn't touch the brake at all.

I did warm the car, for the warming part, is it the engine oil temp is enough for indicatring a car is ready for intense driving?
I think it got ~90-100 degree in about 5~10 mins drive, is that enough? then I can do LC or test runs.

[thejeremyman9]

Originally Posted by Skyhigh

Ok.
Your view is noted.
Agree to disagree. And if you dig a bit deeper in the documentation and statements BMW has made about LC through the years, you will realise that the mode is there for a reason. (If it ain’t fastest possible acceleration, what could it possibly be...)




I rest my case.

Good job digging deep enough to try and find something that supported your conclusion lol. The car already has a rev limiter (assuming you are in manual mode in the first place). Go ahead and site your source for that also.

This text you quoted - "Using a computer program and the innovation of an electronic accelerator, Launch Control delivers safe and optimized acceleration to drivers. It was first designed with racers in mind, but the technology has been installed in both street- and track-specification BMW cars. The system accelerates your car smoothly and quickly, without causing the drive wheels to spin. The system is also designed to take other factors into account and prevent over-revving, as well as the potential clutch and gearbox problems." - does not appear to be from BMW. It from random websites/posts and its the opinions of those people.

[Skyhigh]

Originally Posted by bimmerhw

I did hold the brake while trying LC, maybe I didn't hold it completely is the reason I failed. Later on with my 5.47s test runs, I didn't touch the brake at all.

I did warm the car, for the warming part, is it the engine oil temp is enough for indicatring a car is ready for intense driving?
I think it got ~90-100 degree in about 5~10 mins drive, is that enough? then I can do LC or test runs.

That should be enough, yes. See the user manual above for prerequisites to enable LC. No matter whether you use LC or try it your own way, you would need boost build-up to achieve good 0-100. Meaning you cannot get away without brake-boosting.

[Skyhigh]

Originally Posted by thejeremyman9

Good job digging deep enough to try and find something that supported your conclusion lol. The car already has a rev limiter (assuming you are in manual mode in the first place). Go ahead and site your source for that also.

This text you quoted - "Using a computer program and the innovation of an electronic accelerator, Launch Control delivers safe and optimized acceleration to drivers. It was first designed with racers in mind, but the technology has been installed in both street- and track-specification BMW cars. The system accelerates your car smoothly and quickly, without causing the drive wheels to spin. The system is also designed to take other factors into account and prevent over-revving, as well as the potential clutch and gearbox problems." - does not appear to be from BMW. It from random websites/posts and its the opinions of those people.

I didn't have to dig deep - it is literally the first link that pops up if you google "BMW Launch Control explained". And unfortunately for you, most others agree with it explicitly, including generic ones (not BMW specific). It is simply what a LC feature is all about and the sole reason for any OEM to design and implement it - a controlled and safe (to the extent possible when you intentionally go for a quick take-off!) launch....

https://polish-automotiveindustry.com/launch-control

A launch control system is designed to help a car launch from a standing start as quickly and efficiently as possible. The system uses an electronic accelerator and a computer program to control the engine speed and torque. This allows the car to launch at a high RPM without wheel spin or loss of traction.

It also prevents engine failure that could happen if the engine was revved too high without launch control, and protects the car from clutch and gearbox problems. It helps the driver push their car to its limits without breaking anything!

...

Does Launch Control Damage the Clutch?

If we’re talking about launching your vehicle manually, then yes, it can damage the clutch. However, launch control systems take a lot of the stress off of the clutch by automatically regulating the engine speed and torque. This means that launch control actually protects your clutch from damage, rather than causing it!

Still, if you want your car to last for a long time, it’s always best to avoid launching it quickly. Launch control is designed for situations where speed counts. If you’re just driving around town, there’s no need to use launch control.

Everything I have been saying.

But feel free to remain as stubborn as you are, despite all the facts and "opinions"

[thejeremyman9]

Originally Posted by Skyhigh

I didn't have to dig deep - it is literally the first link that pops up if you google "BMW Launch Control explained". And unfortunately for you, most others agree with it explicitly, including generic ones (not BMW specific). It is simply what a LC feature is all about and the sole reason for any OEM to design and implement it - a controlled and safe (to the extent possible when you intentionally go for a quick take-off!) launch....

https://polish-automotiveindustry.com/launch-control




...



Everything I have been saying.

But feel free to remain as stubborn as you are, despite all the facts and "opinions"

You literally just googled what you wanted to hear until you found random articles that are not from OEMs or other reputable sources that supported your position. I google searched your text and found the articles. These are posts from random people written to get clicks, not technical articles or from OEMs.

https://www.carhp.com/news/the-basic...-an-automobile

https://www.bmwux.com/bmw-launch-control-guide/

Congratulations you know how to use google. Anyone who is going to rely on the information presented in these articles or the other one you cited should go ahead and read them for themselves.