drcollie

There is Launch Control built into the GLK350 which is standard on all European models, but hidden in USA/Canadian vehicles due to liability issues enabling performance modes on SUV-type vehicles.

It can be 'awakened' however by opening this little MB 'Easter Egg'. Once activated, when you want a quick stoplight start you merely hold one foot on the brake pedal - press the throttle to the floor - and when you release the brake the computer will generate max HP and shift close to redline in each gear. Will improve your 0 to 60 times by appx .4 seconds.

IF YOU PRESS ON THE BRAKE AND THROTTLE SIMULTANEOUSLY AND THE ENGINES REVS YOU HAVE FAILED TO ACTIVATE LAUNCH CONTROL. STOP - DO NOT OVER-REV YOUR ENGINE AND FOLLOW THE ACTIVATION PROCEDURE AGAIN.

To engage MB Factory Launch Control:

* Turn Key On but do not start
* Press the Accelerator Pedal three times while depressing and holding the "C"/"S" button that is next to your shift lever.
* Turn Key Off.
* Turn Key On again and depress the ESP button below the Emergency Flasher for 5 seconds, then immediately release and press the "C/S" button again.

Launch control is not activated. Have fun.

Note: All 'launch control' starts will be recorded on the MB DME control data acquisition box and stored in memory, and can be downloaded via Dealer OBD code equipment.

NYCGLK

hmmm interesting...good find, but may I ask what's the source for this info esp. for .4 second improvement of 0-60?

Insideline did report that GLK reacted very well to brake and gas pedal overlap, perhaps this "launch control" was enabled or it's just how it works on GLK.

Also not sure if I understood this correctly. If LC is on and you push brake and gas at the same time engine won't rev???

Also how does all this affect the warranty is another question.

EnigmaAW

interesting!!!!

webada

is there a way to tell if its activated without actually testing it? ie, a signal/status on dash comp?

drcollie

No, because this is not supposed to be something you are to do in the USA. In Germany, the button that activates the C / S switch will light up on a third push and display "L" in the dash, that shows its activated. But in US vehicles that feature appears to be disabled. I think its just a matter of swapping in a circuit board to get the display, probably the 14-pin one that is under the dash marked GER-25595-L TUV. That runs to the trans program circuits, but I'll have to do some current voltage tests to run the traces.

drcollie

The UK Car Magazine did tests with and without Launch Control, the .4 second was their number reached.

Correct on the methodology IF you set the program up correctly.

Warranty? It could be argued that the program exists in the vehicle, therefore it cannot void it. They just mask it for the US market, they didn't remove it.

NYCGLK

Interesting. I haven't tried hard launches, but if GLK in fact reacts well to pedal overlap, is there benefit to rev it too much higher than 2k rpm which is when 100% of torque is available?

The reason I was also asking for the source is that I've been on C and C63 forums and haven't heard anybody talk about LC there. I read new E63 will have official LC.

Have you tried this new "launch control" feature does it really make difference? I'd also keep in mind that 0.4sec difference might not be the same for US cars, as the transmission might be already programmed more aggressively in non "launch" mode.

GLK forum is getting better and better

Baby G

Agree since there are newer owners we are finding more tricks of the trade

AJGLK

I have the same question as NYGLK

Also not sure if I understood this correctly. If LC is on and you push brake and gas at the same time engine won't rev??? if yes that is weird

Tate

Nice find.

But since GLK is an SUV, LC is IMO pointless. 0.4 sec improvement in 0-60 for GLK isn't as significant as say on 911 or GTR.

fishsriz

i tired this yesterday.. didnt work for me.. anyone else have any luck with it???

reyoasian

Has anybody tried this on a Canadian model? Does it work?

dmercado

Canadian model here. Tried it and nothing. Is there some sort of indicator letting you know?

Quite frankly, not sure about this concept of LC. First time I've ever heard of it. Can't understand why simply flooring it would not achieve the same thing.

ben-c

Just flooring an auto trans car means your moving off from idle 800-1000rpms. If you graph an engine's power, any engine, you'll find that max torque is not achieved until usually about 3000rpm and max hp much higher than that. If you could "launch" when the engine is revving in that sweet spot (which is what launch control allows you to do), rather than building up to it from idle rpms, you'll take off much faster.

NYCGLK

see above, 100% of torque in GLK is available at 1500 rpm, so there is no point to rev any higher to launch it.

MilesBFree

The technique of revving the engine while pressing the brakes is called power braking, and was probably invented about 5 minutes after the automatic transmission was.

If NYCGLK is correct (and I have no reason to doubt) then power braking alone would do the job, regardless of whether or not the computer could adjust the revs.

As far as adjusting shift points to be closer to redline, most automatic transmission cars do that when you put it in any gear besides D. If a person was trying for a quick 0-60 ET, then he or she is almost certainly be going to manually shift, so the same thing will be achieved.

Therefore I seriously doubt that launch control mode is going to be good for 0.4 seconds. Unless the baseline to which this is compared is a person simply sitting at a stop sign as usual and hitting the gas with none of the usual sort of techniques as I just described.

The one thing that would help a lot would be if the computer monitored wheel spin while in launch control mode, and modulated the revs to keep the wheels just at the point of spinning so they just don't go up in smoke.

Or if launch control mode engaged a special program to control the transfer case to distribute power better to limit wheel spin. Or if the car had electronically controlled diffs (ala F1) that could be controlled "better" while in launch control mode.

I didn't see any mention of those last two points so far in the discussion, and am not that familiar with the transfer case, diffs, and the control programs to know much about those, but that seems to be where the real benefit would come in to play.

Can anyone shed more light on those?

(And thanks to drcollie, I am not bashing here, just asking more questions to educate myself - I will try this out when we get ours.)

NYCGLK

I have to say that I only read that power braking works well on GLK, tried it briefly with no success. I'm not used to launching cars with auto, (besides just flooring it), as I'm a lil afraid to screw up the tranny.

I almost wanna say that this LC on GLK is a myth, but drcollie seems quite a car enthusiast, so I wanna believe what his is saying.

I honestly think the whole 0-60 is very arbitrary. All euro cars have longer 0-100 (0-62) times, my guess just because the measure it differently.

You read here more on what goes into testing cars here:
http://www.edmunds.com/insideline/do...ticleId=130988

and their test of GLK:
http://www.edmunds.com/insideline/do.../pageId=158004

Last point, it also all depends how tranny is programed after adapting to your driving style, how many miles car has, what type of fuel is used, temperature, elevation etc.

MilesBFree

From the Edmunds link from NYCGLK:

"Acceleration Comments: The GLK responds extremely well to being held against the brakes prior to launching, cutting a full 2/10ths from the 0-60 time. In Sport Drive, the upshifts are reasonably quick and also rather smooth and seamless. Engine note is evident, but it never sounds/feels thrashy."

Sounds like power braking works, but I would have been shocked if it didn't. I do a lot of business travel, and have had the opportunity to beat, I mean drive, a lot of different rental cars. This works wonders on pretty much all cars.

I am not familiar with Sport drive, but we pick our new GLK up at the dealer in a couple of hours, so i am looking forward to it.

NYCGLK

Sport is swithced on by the little C/S button next to shifter. It just makes shift point higher and doesn't rush to upshift as much. On MB's tho, S=Normal, C=Comfort. That's why AMGs now have Sport Plus...lol Can't we just have C N S and not C S S+

ben-c

[quote=MilesBFree;3626463]The technique of revving the engine while pressing the brakes is called power braking, and was probably invented about 5 minutes after the automatic transmission was.

If NYCGLK is correct (and I have no reason to doubt) then power braking alone would do the job, regardless of whether or not the computer could adjust the revs.

I haven't taken delivery yet so I can't verify, but technically you shouldn't be able to power brake a GLK. That's because the tranny is supposed to disengage at a stop when the brakes are applied, like going into N. Once the brake is released the tranny will then reengage and creap forward like a regular automatic.

That's why in those insructions to activiate LC by drcollie, says that "if you throttle and brake simultaneously, you have failed to activate LC". I assume that trying to powerbrake without launch control will be like revving in neutral rather thank loading up the torque, as drcollie goes on to say "do not over rev your engine"

Can anyone verify on a North American GLK whether powerbraking without LC works.

F18BEN

I wouldn't mess with the whole concept. (Unless you are leasing). If you own the car there is no reason to beat it up by either power braking or LC'ing. I must admit, when I was your age I did the same thing. Anyhow enjoy your GLK's.

NYCGLK

+1, it's an SUV not a sports car

billyt

If LC is an available option, it would be such a hugh selling point to all the 7 speed tranny available in other models, and why would MB hide this profitable feature? It doesn't make any sense.

Jaydeath

LC is not a great thing to do to the car. Also, on a 4MATIC since there are 4 drive wheels there is likely to be more damage to the breaks system, tranny, etc... If you want more performance look on the C forum and see what people are doing with their 3.5 engines and mirror them!