coil question

[lostforawhile]

has anyone ever found out the specs on the factory coil? I was looking at performance coil specs, and even the best round coils run out of RPM's around 6500 to 7000. They will produce spark all the way to redline, but it's dropping out at the top end. The factory coils on the three g are built with an E design just like the expensive aftermarket coils, the problem with a round coil is the way the magnetic field collapses during ignition pulses, the coil becomes saturated far to easily and spark drops off. I'm not sure of the exact process but the E design cuts a lot of the coil saturation. I believe it has something to do with the angles of the core cutting across the lines of force. A lot of people say Honda coils are excellent, so it may be best to simply go to a good ignition box and keep the factory coil, I've seen several people on here install round coils, which seem to be a performance drop,not a gain, they are mostly for lower RPM engines. Even the best Accel round coil I saw dropped off at 6500 rpm. It may be a performance upgrade to install the 3G style coil on the older Honda's with the round coil, I seem to remember some of them having a ballast resistor, This would work on ones with the electronic ignition, but I don't believe it would work on points. I think the ballast resistors were just on the points systems.

[lostforawhile]

I was going to bring up a point but I forgot, The round coils may be good until redline, but when they get to the top of their RPM limit, the spark energy the coil can produce has already dropped way off, they aren't linear, they produce most of their spark energy around 2-4000 rpm, then it starts dropping.

[A20A1]

How are you testing the coils?

I thought that listed specs were for V8 which will need to fire twice as much as a 4 Cylinder.

[lostforawhile]

How are you testing the coils?

I thought that listed specs were for V8 which will need to fire twice as much as a 4 Cylinder.

I'm going by the listed specs, Also a V8 usually has more then one cyl firing at one time, The rpm limit is more a factor of coil saturation and hysteresis in the round coils, the coil becomes saturated magnetically at higher RPM's and the field can't collapse and produce spark anymore. I've noticed nearly everyone is going to U shaped and E shaped cores on coils now, they are less subject to hysteresis, I was just thinking that they would be an upgrade to older Honda's with the round coil, all the high performance ignition products are going to the E and U shaped coils now, Honda was one of the first to put that type of coil on a production car.

[Dr_Snooz]

That hysteresis will get you every time.

[A20A1]

I'm going by the listed specs, Also a V8 usually has more then one cyl firing at one time, The rpm limit is more a factor of coil saturation and hysteresis in the round coils, the coil becomes saturated magnetically at higher RPM's and the field can't collapse and produce spark anymore. I've noticed nearly everyone is going to U shaped and E shaped cores on coils now, they are less subject to hysteresis, I was just thinking that they would be an upgrade to older Honda's with the round coil, all the high performance ignition products are going to the E and U shaped coils now, Honda was one of the first to put that type of coil on a production car.

I feel retarded now, should of known that.