Originally Posted by
David T
There have been more than a few instances on this forum where an owner used a non-Bosch coil and later reported early failure. It would seem if you stay with the Bosch coil it is more reliable. There doesn't seem to be any good reason to use anything else. Getting a "hotter", higher voltage coil doesn't show any measurable improvement but it does seem to decrease the reliability. For any owner looking for cheap, "bolt on" HP, there is no magic bullet. You certainly won't find it in an ignition coil. BTW, increasing the spark gap to get a "hotter" spark will increase the stress on the rest of the secondary ignition system. The cap, rotor and wires were not made for that and you can expect them to break down quickly. As for the need for a "hotter" spark, all it is for is to ignite the A/F mixture. Anything more is unnecessary. While it IS true you need a hotter spark at higher combustion pressures (like when the motor is under load during acceleration or going up a hill) the stock parts are more than enough as long as they are in good condition.