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Launch control and clutch switch

Launch Control

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Discussion and questions related to the course Launch Control

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Hello Andre,

I have 2 questions for you.First of all what would be your starting RPM,for ground speed launch control,on a high rev engine.It's a 600cc naturally aspirated engine that revs at 13400 RPM and has a pick torque of 58 Nm at 7400 RPM.

Secondly,I cant understand the idea of the clutch switch.You said that it's a digital input in the videos.The problem is that we use a lever as a clutch on that race car and not a pedal.Is it possible to set up a clutch switch and connect it on a motec m800?And if yes,can you explain how can I install a clutch switch(or describe what it is if you have time) because I really have no idea how to wire this up from clutch to my motec m800.Thanks a lot.

you would need a switch that connects your Launch control wire of the ecu to ground when the clutch is pressed (pulled in your case)

Thx for your reply KennyJ,

I will explain what I understood(sorry but I didnt get it very well).I will use a wire that goes to a digital input on my motec m800.This wire will be connected with a switch.Will the other ending of the switch go to the clutch?(So to be able to activate the switch when the clutch is pressed?).I need to pull a lever to insert first gear and then release that lever to accelarate.Is it possible to use a clutch switch on something like that?

that sound fine yes , i'm an automotive electrician so i only know how to wire

i dont own a motec so maybe someone else knows what settings u should use

Thanks a lot for your interest Kenny!!

There are many variables that you can use here.

When I had my m800 I used ground speed to trigger many things. IE: launch control, boost control, ORB etc.

This might help instead of wiring a switch.

I am intrested in ground speed control.I am going to install 4 hall sensors as 4 digital inputs to my motec m800.Can I set the vehicle in to launch control mode without switch,button etc?If from stand position,press the throttle(for example) 60% while pressing the clutch, is it possible to enable my launch control feature?I can copy paste my inputs in launch control on motec m800 and have your opinion on that.I will attach it.It's N/A engine,600 cc, 13400 rev limiter.I am attaching you 3 pictures of my file on launch control.If you can advise what should I change/add etc. I would really appreciate it

Attached Files

@VTune, yes in the m800 you can use ground speed based launch control without a switch to activate it. There are two parameters that need to be met before the ECU will enter launch control mode - First the throttle position must exceed whatever you have set as the 'Launch Activate Throttle Position' and secondly the value you're using for the x axis in the launch table needs to be less than 1/4 of the maxium value used (usually this would be set to ground speed).

Thanks for your reply Andre.

So to adapt that on my file.I set 70 % "Launch Activate throttle",0 km/h->3500RPM.So now while pressing clutch in stand position if I press the throttle more than 70% I will enable launch and my engine will rev till 3500 RPM(because I set that).And when I release the clutch. my ground speed table will be enabled depending the km/h of the vehicle(x-axis). Thanks again mate.One last question.What would be your initial RPM at stand position if your rev limter is 13.400 RPM?7000?Because,If I am correct, you said that it's better to start higher in RPM and then decrease starting RPM to protect the drivetrain(which has been designed and constructed by students in the university so I need to treat it carefully )

Your start rpm depends on many factors - engine torque, traction and weight are the fundamental ones. This makes it difficult to give an answer that will be applicable to every scenario. In your instance I'd try starting around 6-7000 rpm and see how that works out. If the drivetrain is fragile then I'd also recommend smoothly releasing the clutch rather than side stepping it. This will help reduce shock loading on the drivetrain. Another tip is to load the drivetrain slightly on the clutch prior to launching. This can be done by letting the clutch out slowly until you feel the car start to creep. This means that when you release the clutch the drivetrain is already loaded. Doing this though requires a line lock to stop the car creeping when the revs are brought up.

Very informative reply Andre.Thanks a lot.I will try it as soon as I start this project.

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