Lotus Elan and Lotus Elan Plus 2 Forums

yes the plan was to incorperate a cutoff switch on the dash... im unsure what this ballast resistance is that people are talking about, is this something that should be between the coil and the ig switch? right now I dont think i have that?

Basically, the resistance is in the feed to the ignition coil so that the supply voltage when running normally is about 10 volts. Then when you are cranking the engine over on a cold start and the battery voltage is pulled down to about 10 volts, the resistance is bypassed so you have 10 volts at a 10 volt coil = good spark for starting!
If you have a modern electronic ignition fitted it probably won't need a ballast system or bypass but, check the fitting instructions!

There is no electrical reason to retain the firewall solenoid, at all

Absent starting in very cold weather{IOW weather never seen in England] there is no reason for ballast resistor bypass

The biggest reason for retaining the firewall solenoid is the start button on the bottom

The most widely available gear reduction starters in the US usually have a terminal for the ballast resistor bypass.

For the original poster here is a picture of my Plus 2.

The junction box has two terminal bolts to attach the large cables from the battery & to the starter motor. It has a cover that snaps down.. This provides a large always hot positive terminal under the hood. The other Brown - Hot at All Times Unfused wires are the main alternator charging wire and the loom power to the fusable link.

The fusable Link is also within a plastic box with a snap down cover. The main loom Brown - Hot at All Times Unfused supply runs through this fusable link, so the whole loom is protected. The loom is an aftermarket affair from Spyder that is has a bit different layout from stock; it has a major Brown common junction within the loom. I expect this layout is probably pretty standard if the car is converted to a modern Nippon Denso alternator and the stock voltage regulator (control box) is removed.

The white non-stock connector is for a sub-loom that runs to the electronic ignition which is located inside the car. As mentioned earlier, the electronic ignition eliminates the need for the ballast resistor.

The non-stock small grey box is a windshield wiper controller that provides intermittent wiping.

This layout worked out well for my car as the new fuses and relays are all located on the back wall of the glove box. The main Brown feed is therefore very short and secure. Might work a bit different with a RHD car. I suppose the alternator charging lead could connect to the supply side of a fusable link located on the left side of the car roughly where the voltage regulator is located?), along with a main Brown over to the battery cable junction box located on the right side of the car roughly where the solenoid is now.

HTH

Stu