why_bother
10-12-2007, 07:30 PM
In my travels today I was pondering life amongst a lot of other things (as I do) and was thinking about the article in the wheels magazine about the porsche with the launch control in it.
The way I read it, It limits RPM from standing start to 5000RPM (not rev limit) so that the driver can get a loaded launch from the vehicle and gallop away.
The colt doesn't use a traditional accelerator cable.. it uses an electrical pickoff to transfer a signal (or voltage) to somewhere else in the car..
What's stopping someone from grabbing a multimeter or oscilliscope to see what type of signal is being sent at say.... 2500RPM (or a different nominated launch RPM) and imitating that via a momentary switch that is only activated in 1st gear (via a microswitch below the gearstick).
I'm thinking, to do it properly you'd disconnect (via a relay) the existing signal from the signal amplifier(?) on the accelerator that goes to the computer(?) (correct me if i'm wrong, haven't seen any schematics) and add in (on the same relay (2 sets of contacts)) the new signal (12V DC with some fixed value resistors to get desired voltage (aka RPM)).
Bored motoring ramblings? could very well be, but at least it's though provoking.
I haven't seen any inverters in the vehicle so I assume the signal is a DC level.
Could you see it now? sitting at the lights, hold in this magical button & RPM rises (all while your foot is to the floor) and on launch, it just takes off and once you let go of the button, it's back to full voltage (RPM). Even throw in a trim pot, so you can dial in a voltage (RPM). mmmm electronics...
The way I read it, It limits RPM from standing start to 5000RPM (not rev limit) so that the driver can get a loaded launch from the vehicle and gallop away.
The colt doesn't use a traditional accelerator cable.. it uses an electrical pickoff to transfer a signal (or voltage) to somewhere else in the car..
What's stopping someone from grabbing a multimeter or oscilliscope to see what type of signal is being sent at say.... 2500RPM (or a different nominated launch RPM) and imitating that via a momentary switch that is only activated in 1st gear (via a microswitch below the gearstick).
I'm thinking, to do it properly you'd disconnect (via a relay) the existing signal from the signal amplifier(?) on the accelerator that goes to the computer(?) (correct me if i'm wrong, haven't seen any schematics) and add in (on the same relay (2 sets of contacts)) the new signal (12V DC with some fixed value resistors to get desired voltage (aka RPM)).
Bored motoring ramblings? could very well be, but at least it's though provoking.
I haven't seen any inverters in the vehicle so I assume the signal is a DC level.
Could you see it now? sitting at the lights, hold in this magical button & RPM rises (all while your foot is to the floor) and on launch, it just takes off and once you let go of the button, it's back to full voltage (RPM). Even throw in a trim pot, so you can dial in a voltage (RPM). mmmm electronics...