launch control or anti lag?

[adamw]

ive seen quite a few videos with a s2 at the starting line, it revs to say 5000rpm and you can clearly hear the turbo building boost before the green light?

http://www.youtube.com/watch?v=vxIOyBlxCGM

is that launch control or anti lag?

and then you have a s2 sitting there and all you hear is RAAAPAPAPABANG!!!

http://www.youtube.com/watch?v=z-Buo_5G9kU

1:45
what is this? and more importantly... can i get it?!


i know there are a few people on here has it/knows some one who has it... but ive serched on here and cant find anything

[lind4hl]

Yes Launch control, dont know how it is woth Motronic and this most aftermarket ECU´s has it..

EDit:

Anti Lag system is when you change gears, the ECU send in fuel and retards the timing = the "explosion" is in the ex-manifold and produces alot of exhaust gasses to keep turbo spinning, not healthy for the turbo though..

[adamw]

also How does launch control work?

[pnanassy]

depends on what ECU we are talking about.they usually limit the rpm (lower than normal rpm limit),and retard the ignition.
Also,some can add some extra fuel.

On 2WD cars it makes sense to read wheel speeds.On a 4wd you can use timer to optimize traction in the first seconds of the start.

HTH,
Peter

[a4kquattro]

yes, launch control. Most commonly done on standalone ecus such as VEMS, typically you integrate it with the clutch pedal so that when enabled with a switch on the dash sitting at the lights you mash the pedal to the floor, the ecu then retards the timing drastically so that the mixture is burning when the exhaust valves are open, causing the turbo to spin up dramatically. The ecu also adds fuel to keep EGTs under control and limits the redline to a lower level. You dont want to be 'on the button' too long, as the temperatures get very hot very quickly...

[QuattroFever]

another option is to use a soft cut rpm limit for say 4500rpm. Then use the stab valve to bypass the throttle and allow the engine rpm to climb to that limit whilst at the same time retarding ignition.
Set launch deactivation once TPS hits a preset threshold.
This way you just flick a switch and it sets it all for you, just feed the clutch in.

[adamw]

Thanks for the replys. So launch control would be a quite easy to set up and use? Because its just a extra on VEMS? where as anti lag would be more tricky?

Whats peoples thoughts on this for a everyday car?(obviously not used everyday) reliability? And who has launch control in ther daily car?

Thanks adam

[lind4hl]

launch control do not "hurt" the engine if you´re not using it, so on a daily no problem really..

[adamw]

I know but what i ment was... Would there be any reliability issues if i used launch control once a week ina daily driver?

[lind4hl]

of cours ethe turbo will get more stress on it,, but nothing major..

[a4kquattro]

if used correctly there is no problem using launch control on a daily driver. the key is to not stay on it for too long at a time.

[pnanassy]

One of my ex-racecars just dropped a stock exhaust valve.The guy used the ALS and Launch too much.I told him that this will happen about 2 years ago,and asked him to remap his drag oriented mapping,with no effect.Sad thing is in the story that he just sold the car,and the new owner got this "small" problem after 2 days.

Be warned,if use too much ,the already stressed stock components can and WILL fail.

if used correctly there is no problem using launch control on a daily driver. the key is to not stay on it for too long at a time.

[|Maku|]

Has anyone done/seen a launch control on Motronic?

[max_s2]

Cheapest way is to use a rotor (the one that comes inside dizzy) from an older one audi that has its own rev-limiter inside, it cuts spark so boosts up. There is a need to make few adjustments to the whole thing to work. I dont know what exactly has to be re-made or else what, but I've seen an S2 that had this thing
The only problem is that you will not rev or drive your car 6000+rpm but otherways - you have as launch control


p.s. This will work only on an 3B engine.

[S2central.net]

I had never realised that launch control was so crude with that retarded ignition trick - it may be crude but it seems very effective way to build boost on the launch pad... Would require some very clever trick to make this work on Motronic - I'm not even going to try that.

It might be possible to add a delay line between ECU spark control and the POS - with variable control - so that when the 'launch' button is pressed that the spark signals are delayed by some milliseconds to give this retarded ignition... Could automatically time out after a set number of seconds, when vehicle speed exceeds a set limit, or when revs drop below set point (or whatever) - probably best triggered by another delay that is gated by the clutch pedal. Thats what I would try if I had the time and inclination, but its no small undertaking - would be expensive and complex to do digitally - perhaps better to do this with funky analog bucket brigade and some such... As long as delay times can be controlled for best effect then it should work fine.