Launch control for Motronic

[S2central.net]

I'd love to see the drivetrain and tyres that could sustain a launch above 1bar boost on a regular basis. I was impressed with the quick test I had yesterday. Hopefully some gtech data will backup my neck muscles !

[prj]

That's not what I said; I said that the boost will be low, not that htere will be no boost. It will be interesting to try this and see how it operates.

0.7 bar is not low on launch with a K24. Also, there is no way you are going to get this much boost without launching off the revlimiter, which is murder for the drivetrain.
It's enough for wheelspin. I don't think playing with the clutch is a good idea, as you might just burn it and not start at all.

Maybe if you fit drag slicks, the 0.7 bar will not be enough.
I mean, I showed you the video. You can clearly see I get wheelspin.
On a S2, which weighs way less than my S6 the effect will be even more pronounced.
Paul's car spun wheels at only 4000 rpm on dry tarmac and winter tyres. With bone stock ECU, no tuning except the launch control.

[Rusty]

That's not what I said; I said that the boost will be low, not that htere will be no boost. It will be interesting to try this and see how it operates.

[prj]

Based on the fact that boost will be similarly low to that of a launch on a stock ECU, IME, you cannot just dump the clutch, even at 5000rpm, you need to bring the clutch up quickly but also allow a little boost to build at the same time, such that the engine does not bog down and you achieve a little chirp of the tyres. This system makes holding the RPM simple but it will still require some finesse on the left foot. To get the wheels to spin, you'll need to be very rough with it for sure!

You are wrong here.
You assume that no boost is built, but there is. It is nothing like playing with the gas, because you are WOT and turbo is spooling up.

I get 0.7 bar boost just pushing down the pedal and holding it with the current implementation.
Your turbo is already spooled up and when you dump the clutch it instantly boosts, there is no bogging down whatsoever.
This is for stock turbo.

A larger turbo will not build as much boost, but as long as fuel cut rate can be adjusted, it's possible to build boost without dumping unburned fuel into the exhaust manifold.

I posted videos, here is a video of my car on dry tarmac. All I do is hold down the gas and dump the clutch. My 1.7 tonne UrS6 Avant easily spins it's wheels and keeps spinning:

http://www.youtube.com/watch?v=SgQPEpS25as&hd=1

[Rusty]

Based on the fact that boost will be similarly low to that of a launch on a stock ECU, IME, you cannot just dump the clutch, even at 5000rpm, you need to bring the clutch up quickly but also allow a little boost to build at the same time, such that the engine does not bog down and you achieve a little chirp of the tyres. This system makes holding the RPM simple but it will still require some finesse on the left foot. To get the wheels to spin, you'll need to be very rough with it for sure!

[S2central.net]

I think its fair to say that ALS could seriously shorten life of the turbo - its no surprise that its popular in drag / race / rally applications - should be fun to develop it as proof that it can be done... suggest kept for special occasions for most people - like launching away from that unsuspecting EVO-X beside you at the lights - by which I mean Santa Pod raceway.

[Acidburn]

ALS and FFS are a bit further out - personally I think egt monitoring is needed as a minimum so that user can manually turn ALS off if temps get too high, but there are plenty unused ecu pins that could be used for automatic mode of operation.

I'd be very interested in ALS when that comes available, i'll make sure to have a EGT gauge in the car ready

[prj]

Even with EGT feedback it is possible to do nasty things to the exhaust manifold and turbine. ALS should not really be used by the masses on a street car.

Launch control is fairly harmless by comparison. As long as you get some wheelspin and your gearbox and clutch are solid, nothing bad should happen. Although of course it places more stress on the drivetrain, so as always - care must be taken and me nor Paul can not take any responsibility for what happens to your car on repetitive 5000 rpm clutch dumps.

[S2central.net]

Agreed on the restrictor issue - you are running some custom chip from MRC already unless I am confusing you with someone else. Is no problem adding launch to that if you wish...

ALS and FFS are a bit further out - personally I think egt monitoring is needed as a minimum so that user can manually turn ALS off if temps get too high, but there are plenty unused ecu pins that could be used for automatic mode of operation.

[prj]

If you are running a restrictor, I don't think there will be much benefit to running a hot film MAF. You would also benefit from custom mapping the car, rather than running a generic upgrade.

The flat shift kit is still some time away, but Paul is planning on making it modular, so you will be able to fit it yourself with only a chip change.
Antilag is very possible, but as I have said before - it's too dangerous for the average user. That said, I will experiment with it.

[A1quattro]

just what i wanted

hi, very excited these mods will suit me more than most ,as i rally a ur fitted with rs2 engine and ecu ,you can put me down for 1 conversion @ discount price i have 2 questions , 1/as i have to run a 34mm air restrictor ,this gives higher torque low down rev range almost 400ftib , higher up the revs are resricted [34mm] so dont realy rev much past say 5k in gear only in top gear and at start line . will i benefit from fitting a rs4 [think its m5]airflow mtr instead of the standard s2 which i currently use or is it unlikely that the s2 unit running out of its parometers. 2/ ant-i lag would help me ,but due to noise regulations at rallys i would have to run a mild anti- lag ,even if it gave me 0.5-1 psi this would help a lot,so i am interested in this as well . the car is fitted with a o1e dog gearbox so i dont need to use the clutch changing up threw the box ,the flat shift kit would also realy be something that i would like to have . ray

[Rusty]

That's good to know. Will see how the clutch fares with the new blower then

[S2central.net]

the launch code gets injected to whatever chips you have.

[Rusty]

Is this separate to the chips that the car is running, or is it integral to them?

[Jonas_R]

Ok that would be nice