Aftermarket Ignition coils

What makes an aftermarket ignition coil better or worse than an OEM version? When is it necessary for you to upgrade your ignition coils to aftermarket.

Hi. I have tried a few different aftermarket options from middle to high price range and my experience tells me it's not worth it. But it depends on a particular car brend a lot. For instance, Mitsubishi stock ignition coils are very good up to 500+ hp. I guess then you go above 100+ hp per cylinder it would become better off to get stronger ignition spark ( that is privided by aftermarket coils). Having said that we need to remember that a good spark is always a benefit regardless of power level as it helps low RPM range torque and fuel economy...

Bottom line is a higher performance - voltage and/or current - coil won't add power if the OEM is already sufficient.

However, there are times when the OEM is barely capable of meeting the stock ignition requirements - early GM HEI for instance.

The main limitations of coils are RPM limitations due to required dwell to 'recharge'them, and the output voltage - increasing spark gap, cylinder pressures and/or difficult to ignite fuel mixtures can be a problem.

Not much direct help to you, especially as you don't mention the vehicle in mind - some OEM coils are actually regarded as high-performance replacement parts for other vehicles' coils.

You should be able to find the limits of your OEM coil(s) in discussion boards on your vehicle/engine, or in practice you may find you have a misfire on one or more cylinders, which 'may' be accompanied by a 'lean' condition because of unused oxygen in the exhaust - NOTE, this is not common as the other hot combustion gases will usually ignite it in the exhaust and it can be heard as a backfire. 'Lean' may also be a true lean condition, so treat any indications of that with caution - heck, sometimes a rich misfire can show as lean, if the fuel is too rich to ignite.