[DonWG]

Originally Posted by DR BOOST

if the w/s system had enough capacity, why would the quicker cars need to keep closing the plug gap in order to prevent misfires.

There are two different reasons why you close the spark plug gap in a high boost situation.

As cylinder pressures increase and fuel mixtures get richer, it takes more voltage to initiate the spark across the plug gap.

Number one reason why you close the gap: The ignition system is not capable of providing the voltage necessary to initiate the spark under those harsh conditions, so you close the gap to make it easier for the spark to jump the gap using a lower voltage level.

Number two reason: The system has plenty of reserve capacity and is more than capable of initiating a spark across a wide gap in those harsh circumstances, but you close the gap to control the level of the secondary voltage.
Explanation: When you force an ignition system to use higher secondary voltage (assuming the particular system is capable of providing this high level of voltage) to jump a spark plug gap by increasing the gap and/or creating a harsher environment in the cylinder, you run into other problems. Strong coronas build around the spark plug ends, increased chance of cross firing, secondary insulation breakdown, shorter ignition wire life, increased spark plug wear and cap and rotor wear, shorter coil life. Basically, it's unnecessarily hard on the whole secondary ignition system. The trick is to close the gap to control the secondary kv level, and not so much as to start causing miss-firing.

I run a .032" gap on alcohol and 32 psi boost. I've run larger gaps with this system with no problem. Electromotive recommends an even smaller gap than .032 for my application. The only reason they recommend that is to save against undue wear of the secondary system. There is more than enough capacity. And no MSD boxes to worry about failing.

I know some are into the 'whose got the most electronics on their car thing', but I believe in obtaining the desired result with the least amount of electronics. Less to go wrong.