For all you electronic tinkerers, I’m posting a circuit diagram for an adjustable rpm switch. It’s something you can use to activate solenoids for auxiliary ports, VDI, shift light, or anything else you can think of. The circuit is adapted from a rev-limiter circuit for rotaries.In particular, I’d like to thank Rob Weinstock from the fc3s.org list for his help tweaking it. I built and installed two of these switches in June when I did a VDI swap, and so far they’ve been working fine. Parts cost per switch is only about $10 CAD! Note my installed photo, I’ve mounted them away from heat, as I don’t know how that might affect the components. Also, not shown in the circuit layout, I added LED indicators for power, and the ‘switched on’ state.
One other note – I had been looking at the S5 FSM, and noted that the aux. ports and VDI only operate under load. I have a GXL, which came with auto-adjusting suspension. Part of that system is a switch on the accelerator pedal, which sends a 12V signal to the AAS computer above about half throttle. To approximate the ‘under load’ effect, I took the 12V power for the rpm switches from this switch, so they only operate when I ‘floor it’. Just something you might want to try if you’re doing the VDI swap or changing your aux. ports to electronic activation.

 

circuit schematic:

 

installed switches:

 

Great Work! I wish this would've came along a while ago when I was looking around for them... $50-70 a pop my ***!

 

Archive! Archive! Archive!

 

Nice work