I was wondering what ignition mods would benefit from an increased plug gap. Right now I'm running bosch platnums because they are just slightly longer than Acell header shorty plugs and clear my TES headers. I'm also running MSD 8.5mm superconductor wires, an accel super coil, and a holley anihilator hei module. Would these mods work better with an increased plug gap?

Thanks,
R

Thats on the LG4 based '84

 

I'm running .045 gap on mine right now and it runs well.

 

Some people think you get a bit more power with a wider gap.

 

widening the gap has the potential to create a longer spark and help the fuel burn more completely. It draws more juice from the coil though, so a good aftermarket one should be used.
the downside is increased chance of detonation and maybe even have to reduce timing.

I experimented with as much as .065 gap, any more than 12* initial and it would ping bad

seemed like I got better fuel economy, but i have no evidence to back that up.

 

Stock is .035.

With the in cap coil HEI's GM was recommending .045

 

Why do nitrous systems require a smaller gap? Is it a a/f density mix issue, or does a smaller gap make for a more controlled explosion? Fer instance, my 2.8 V6 wants an 0.45 gap... I've played with the gap when I had just an Accel coil, and then when I the MSD 6AL box and Blaster SS coil, and couldn't really go much higher before I smelled fumes at idle. But anyway, stock requirse 0.045 gap- what happens if I run nitrous, and have to drop the gap to 0.035? I won't use nitrous on the street, just the track (no lame comments about supercharging or turbo'ing, the 2.8 ain't worth that kind of cash), so would I have to run 0.045 gap on the street, then 0.035 gap when I go to the track? And how would the smaller gap affect normal driveability? How's that for a question attack?

 

Using an MSD Control Box and a good Coil/ Wires will allow you to use a larger plug gap and create a better cleaner burn. This does improve gas milage and power.

The problem with a wider gap is that it needs more power to make the spark arc the extra distance. With an MSD control box this is not a problem and you should be able to run up to a .50 plug gap on a carbed V8 and a .60 plug gap for a V6.

Now for nitrous, the problem with large plug gap is that the nitrous and extra fuel are being injected at a high RPM in addition to the normal amount of fuel. This causes a very violent AiR Fuel Nitrous Charge to enter the cylinder and can "Blow Out" the spark if the gap is to wide and cause misfire.

My Suggestion is to at least use a Good Control Box and some good wires if you plan on opening up the gap.