[Anterialis]

Hi!
In order to enter "launch control" (e.g. on the new G05), a set of criteria have to be met. I believe those are "traction ON", shifter in "sport", a hot engine (driven at least 10 km / 6 miles? Probably more..), fully depressed brake pedal (left foot) and the gas pedal beyond the "kick down" point . As far as I know, the only way to know if these criteria are met, is to actually execute those commands and at the end fully depress the gas pedal. Then you should get the flag symbol in the dashboard letting you know the car will launch once the break pedal is released (within 3 seconds I believe).

Problem is, if you have forgotten to do one of the steps (e.g. Traction is not set, or the engine isn't just hot enough), the car will end up trying to go forward against locked wheels. This feeling is quite bad, it just feels terrible "wrong". Like just depressing the brakes and the gas pedal simultaneously on any random car. It can't be good.

So to my point: is there any way to know if the car actually willl enter launch mode before the final step of depressing the gas pedal beyond the kick down point?

The best way I've figured out so far is to rapidly depress the gas pedal beyond the kick down point and quickly releasing it, fast enough so that the engine doesn't have enough time to develop any real power. I guess this would work with normal (non PHEV) cars, but with the 45e, since the electric torque is instantaneous, even this doesn't quite work. But its better than nothing.

Thanks for your replies! =) And sorry for the grammar, English is not my main language.

(and thanks for a great forum!)

[flyinglarry]

There would be a flag and "Launch Control Activated" shown in the centre of your dash.

[Anterialis]

Originally Posted by flyinglarry

There would be a flag and "Launch Control Activated" shown in the centre of your dash.

But my point is that the flag shows up only after you floor it. And if you floor it, expecting it to work, and it doesn’t, you are embarrassing yourself... How can I know it will work before stepping on both the brakes and the accelerator at the same time?

[flyinglarry]

Originally Posted by Anterialis

But my point is that the flag shows up only after you floor it. And if you floor it, expecting it to work, and it doesn’t, you are embarrassing yourself... How can I know it will work before stepping on both the breaks and the accelerator at the same time?

When you press the gas pedal down, if it stays the max at 3000-35000rpm, then you can tell the launch control is engaged successfully. If it went beyond 3500 rpm, you would either just launch it at higher RPM, or you abandon doing it.

Usually it works every time for me. Just follow the launch sequence.

[AndroidRobot]

first of all traction control needs to be OFF ie one press of the traction button.

to use launch control do the following (I've posted this several times now)

Drive mode: Sport+
Gear lever: Sport
Traction control: Off (not the same as DSC off)
Autohodl: off (not required but you should)
mash the brake the the floor then kick down the gas pedal, it will rev to ~2800rpm and hold there)

launch control flag comes up, let off the brake with your foot firmly on the gas


now, I don't like the factory launch control, I launch with DSC off and always get better times than using launch control

[Anterialis]

Originally Posted by AndroidRobot

first of all traction control needs to be OFF ie one press of the traction button.

to use launch control do the following (I've posted this several times now)

Drive mode: Sport+
Gear lever: Sport
Traction control: Off (not the same as DSC off)
Autohodl: off (not required but you should)
mash the brake the the floor then kick down the gas pedal, it will rev to ~2800rpm and hold there)

launch control flag comes up, let off the brake with your foot firmly on the gas


now, I don't like the factory launch control, I launch with DSC off and always get better times than using launch control

Thanks for the input. Maybe its a languange barrier thing, but I dont understand why ppl keep posting the recipe on how to launch the car. It is clearly stated in the manual how to do it. But sometimes it does not work even though you are doing everything right, because some of the criteria cannot be directly entered (like enabling DTC mode). My question is in regard to the criteria we do not have direct control over. Selecting "traction" / DSC off and putting the gear lever into "sport" is something we control and can check visually. Whether the engine is hot enough or the car believes it has travelled the required 10 km or whatever (hard to know exactly when driving a hybrid, maybe 12 of the last 20 km is in hybrid/electric mode, meaning only 8 km is driven using the fossil engine, thereby the criteria is not met).

Im sure several ppl, at least during the first times trying out this launch feature, will mess something up, e.g. forgetting to put the steptronic into S mode, leaving it in M mode. If there was as symbol showing before one presses the gas pedal beyond the kick down point, less ppl would make the car do something it is not meant for (engine working hard to go forward while stepping hard on the breaks), in my opinion.

Tapping the gas pedal quickly beyond the kick down point and letting go immediately, looking for the flag symbol, seems to be the best option to verify the car is ready to enter launch mode.

Thanks again for the inputs!

EDIT: To be clear (I might have been unclear in my initial post). I think its important to distinguish between "dynamic stability control" e.g. "DSC", and "dynamic traction control" e.g. "DTC" or "traction mode". At start up, DSC is enabled. Quick press the DSC button activates DTC, a sub-function of the DSC system. Long-pressing the DSC button deactivates DSC completely. When talking about launch control, DTC (traction mode) has to be activated. I am unsure if the car will launch when DSC is completely off (long-pressing the button). Inputs?

[AndroidRobot]

Originally Posted by Anterialis

Thanks for the input. Maybe its a languange barrier thing, but I dont understand why ppl keep posting the recipe on how to launch the car. It is clearly stated in the manual how to do it. But sometimes it does not work even though you are doing everything right, because some of the criteria cannot be directly entered (like enabling DTC mode). My question is in regard to the criteria we do not have direct control over. Selecting "traction" / DSC off and putting the gear leaver into "sport" is something we control and can check visually. Whether the engine is hot enough or the car believes it has travelled the required 10 km or whatever (hard to know exactly when driving a hybrid, maybe 12 of the last 20 km is in hybrid/electric mode, meaning only 8 km is driven using the fossil engine, thereby the criteria is not met).


Im sure several ppl, at least during the first times trying out this launch feature, will mess something up, e.g. forgetting to put the steptronic into S mode, leaving it in M mode, if there was as symbol showing before one presses the gas pedal beyond the kick down point. Less ppl would make the car do something it is not meant for (engine working hard to go forward while stepping hard on the breaks) this way, in my opinion.

Tapping the gas pedal quickly beyond the kick down point at letting go immediately, looking for the flag symbol, seems to be the best option to verify the car is ready to enter launch mode.

Thanks again for the inputs!

EDIT: To be clear (I might have been unclear in my initial post). I think its important to distinguish between "dynamic stability control" e.g. "DSC", and "dynamic traction control" e.g. "DTC" or "traction mode". At start up, DSC is enabled. Quick push on the DSC button activates DTC, a sub-function of the DSC system. Long-pressing the DSC button deactivates DSC completely. When talking about launch control, DTC (traction mode) has to be activated. I am unsure if the car will launch when DSC is completely off (long-pressing the button). Inputs?

I can launch the car after I start it and the engine idles down to the normal rev range. There's not a 10mile minimum that I've seen. Granted, as you know, launching the car while the oil isn't at temp can create a temperature gradient across the turbo impeller which fatigues the material more. The best time I ever did with DSC off in my 50i (MY19 here in the US). was 4.05s, recently the best time I've gotten is 4.17s, these are hard to do on a non-prepped surface. It really varies based on temperature here since it gets rather hot, even while cold I'm on summer tires so I fight for traction. Launching with DSC off, I can spin all 4 tires sometimes to give you an idea.

[DgjoX6M2016]

I think it's a good point. There could be an indicator for 'Launch Mode Available' to indicate system ready. Perhaps a small flag somewhere.

[AndroidRobot]

Originally Posted by DgjoX6M2016

I think it's a good point. There could be an indicator for 'Launch Mode Available' to indicate system ready. Perhaps a small flag somewhere.

there is one when you kick down with the conditions met. I don't know why this is an issue, even if the flag doesn't appear you still fly off the line. LC isn't even that good vs proper launches as noted above. I can show my draggy data comparing the two, it's a pretty big difference.

[X5_CC]

Originally Posted by Anterialis

Problem is, if you have forgotten to do one of the steps (e.g. Traction is not set, or the engine isn't just hot enough), the car will end up trying to go forward against locked wheels. This feeling is quite bad, it just feels terrible "wrong". Like just depressing the breaks and the gas pedal simultaneously on any random car. It can't be good.

First off to answer your question, no, there isn't a way to know if you've done everything right before pressing the kick-down switch and potentially seeing the flag.

However, in regards to your quoted question above — if you feel fine using launch control, you should feel fine with "the car trying to go forward against locked wheels" as in your quote. That's exactly what launch control does anyway. The brakes hold the car still while the engine revs up to a specified RPM, building boost and spinning against a half stationary torque converter. Mechanically there's no more stress on the system in your quoted concern than if you were to do the correct checklist and use launch control. In fact it may be more stress using launch control because there was a report here once that the engine (at least 50i models) builds even more boost than normal when in the launch control program.

[Anterialis]

Originally Posted by X5_CC

First off to answer your question, no, there isn't a way to know if you've done everything right before pressing the kick-down switch and potentially seeing the flag.

However, in regards to your quoted question above — if you feel fine using launch control, you should feel fine with "the car trying to go forward against locked wheels" as in your quote. That's exactly what launch control does anyway. The brakes hold the car still while the engine revs up to a specified RPM, building boost and spinning against a half stationary torque converter. Mechanically there's no more stress on the system in your quoted concern than if you were to do the correct checklist and use launch control. In fact it may be more stress using launch control because there was a report here once that the engine (at least 50i models) builds even more boost than normal when in the launch control program.

This is very interesting! I was sure the launch control would NOT put pressure on the drive shaft as long as the brake pedal was depressed, only engaging once the brake pedal was let go of. Like revving with the clutch engaged on a stick shift. I thought the launch control was something like popping the clutch on a manual. Then what is the point with LC? Are there documentation to support this? If that is the case I totally rest my case. Thanks!

I remember on the E46 M3 the LC was activated by holding the electronic gear lever upwards (?) revving the engine (you didn’t have to press the brake pedal I believe), and letting go of the gear lever. That felt like popping the clutch, not the gas and break simultaneously feeling...

Edit: think I found an article explaining it all. Supports what you wrote


https://www.xhpflashtool.com/blog/la...rol_explained/

“But there are more things to consider with LC, when running a car that isn't really stock. There's for example the procedure with pressing the brake and flooring the throttle. On a DCT (double clutch transmission) transmission the trans would be in idle position in that situation and there wouldn't be any power-flow to the rear wheels unless you release the brake. On a torque converter Automatic like the ZF8HP, there is always power-flow to the rears, as soon as you are in D/S or M mode. This means when going full throttle the engine will be instantly transmitting torque to your rear wheels and the brake has to overcome that momentum to keep the car standing still. This works without issue on a stock car, but on tuned cars with lifted torque limiters the engine can actually outpferform the rear brakes and they will start to spin, no matter how hard you press the brake. This does not mean LC is broken, this does only mean your rear brakes can't hold the power anymore.

The solution is simple: Don't let the car boost that high, before releasing the brake. Just release the brake quickly, around 1 sec after going full throttle. This is also a major difference between LC mode on a DCT (Double-Clutch) Transmission and a Torque-Converter Auto. With the DCT the procedure holds a certain pre-set RPM (that's what creates that crazy sound on M-Cars) before dumping the clutch once the driver releases the brake. On a torque converter trans the engine just presses with maximum force against the torque converter until you release the brake. So the RPM you reach while standing still is not controlled. It's just the outcome of engine power vs. the torque converter. (means the RPM will vary depending on engine power) So once the car is tuned, it is to some extent the drivers responsibility to release the brake at the right time.”

[homerrr]

If you haven't used it yet, you should, even just once... only three pre-requisite conditions really; push the traction button, go sport plus, select sport transmission. Full brakes, the full throttle and LEGO of brakes....so much more simple then the manual makes it seem. Not planning on using it, but gotta try it at least once right?!

[Anterialis]

Used it several times, it’s great fun

Btw, updated my last post.

[DgjoX6M2016]

Originally Posted by AndroidRobot

there is one when you kick down with the conditions met. I don't know why this is an issue, even if the flag doesn't appear you still fly off the line. LC isn't even that good vs proper launches as noted above. I can show my draggy data comparing the two, it's a pretty big difference.

Yah. I equate it to power shifting back in the day. My f86 launch is brutal, the gear whine is different, no loss of acceleration between shifts.
, and power is delivered with a tsunami of thrust until you lose the nerve of foot in throttle. It's bat shit crazy. That's why the oil and fluids need to be at teMp. I look for opportunities to use.

I wasn't aware out G05 has that.