Unusual alarm idea

[Sam_Q]

When I was working on my engine I accidently swapped two igniton leads and when I started it it idled ok but it let out constant backfiring. Now I had the idea that I could incorperate that into an alarm. It would only work if I had 4 individual coils, and I would have 2 relays to cross over the input signal to two of the ignitors that cross back when a hidden switch is activated and the ignition is on. So if someone was to hotwire my car on when he would start it it would make a total rachet. This would be more effective than an alarm siren I think and very hard to understand to anyone why it is doing it.

what do you think? genious or stupidity?

[river]

Hi,

Not really necessary is it, considering a good alarm set up will stop the engine from starting or firing in the first place. Furthermore, swapping the leads can stuff the engine if the theif is determiend to keep driving the car.

seeyuzz
river

[Sam_Q]

call me paranoid but give me an alarm and I can bypass it, just pull the 2 relays out and plug 2 wires in. How would it damage the engine?

[ScottBlack]

it damages the motor by the wrong cylinder firing, as in if number 1 is ment to spark, and number 2 does, it might ignight whats in that cylinder and try to push it the wrong way, its alot worse than having the timing out and having the motor ping

[ajh]

Tip: Drive an old SV21 with faded paint. ( If you can bear it) Mind you, my wife loves her one!

It'll go forever, but nobody will knock it off because they're like an arse - Everyones got one!!

Seriously, an alarm and/or immobilisor, and a decent insurance policy. Most insurance co's give a discount for either of the above too.

[Sam_Q]

I really doubt that, because pinging is like a hammering force that is meant to be 1000x the force of a normal combustion. Well if it is is so which I am not ruling out I would rather risk losing an engine than a car. Because the person wouldnt get far with 2 cylenders.

[river]

Hi,

Yes... what ScottBlack said.

Anyone with the right skills and determination can bypass just about any alarm. It's not a real big task. The alarm is there to hopefully stop the bypassing-theif - making it a better choice for them to find a more easy car to steal. But, they won't stop a determined professional who needs/wants your car.

seeyuzz
river

[river]

Hi,

Well if you can bypass an alarm so easily... what's to stop someone doing the same to your set-up? I can see no purpose in your alarm proposal as it allows the car to be still driven, albeit slowly and causing major damage to the engine.

seeyuzz
river

[BradW]

We made a "immobiliser" when I was a 1st yr apprentice. It was a timing circuit that would allow the car to run for 30secs, cut the engine out for 30 secs, let it run for 30 secs, etc. The theory was that with the engine running, cutting out, being hard to start, running again,etc, the theif would get the shits and leave the car, hopefully without causing too much damage. Maybe another option as the circuit would not be hard to make.

[Jorrs]

or drive it thirty seconds onto busy freeway, motor cuts, B double sandwiches it.. i guess there would be slight justice though.

[BradW]

If you think about it, how long does it take to start your car, back out of a parking spot and drive out of a car park. Chances are the car would stop at least once before you hit the road (assuming the car isn't already parked on the road ). Also you could set up the on/ off times to whatever you wanted.
All that said though, if they really want your car, all they need is a tilt tray.

[worldwalker]

have you thought of welding the alarm in? then having a mircro key kill switch hidden which is also welded in. A prick if it fails but no one can disarm it. A part of the system would also need a dead-bolt on the bonnet.

[Negative Boost]

I still like one of the AW11 boys idea on putting the 130db siren inside the cabin

[ajh]

After they bypass the alarm is when the insurance kicks in.

Sure, you might have lost your pride and joy and have to walk home, but hopefully they go joyriding, write the car off and you end up with a sum of money sufficient to replace it......

[ViPeR_NiPPleX]

I still like one of the AW11 boys idea on putting the 130db siren inside the cabin

Wait for that one to backfire in your ear