P-Mags and Auto Plugs: Two Questions

[B25Flyer]

Doug,
Do you have the specs on the D9 plugs? Are they 18mm plugs? I tried to find the heat range, but was unsuccessful. I am guessing based on other D series plugs it is a 9.

I have an ElectroAir with Autolite 386 (heat range 8) on the bottom of my O-360 carb. I don't have any detonation issues and engine runs great, but I am fighting high CHT issues. Did you notice a change from the 386 to D9 Plugs?

Rockauto.com has D9 plugs for $1.94.

Dan

I did not notice a difference in CHT except for when the preignition/detonation started.... I talked to a guy who is a the spark plug guru for the reno racer and he recommended the D9s. if you have stock pistons D16s or 386's might be fine...

I am not clear on how hotter plugs make the CHTs go up? Some one enlighten me? To my way of thinking Colder plugs move heat from the plug to the head faster than hotter ones, but at the end of the day, the amount of fuel being burned and heat generated is the same, hotter plugs just burn the deposits off more effectively... What am I missing here

Tailwinds,
Doug Rozendaal
F-1 EVO

 

[mike newall]

Mehrdad,

One thing to consider with P-Mags is the delay in firing as the start sequence is initiated.

When Brad designed the ignition, he worked with Sky-Tec and also the guys with composite sumps and introduced Run Mode Starting Delay.

It allows the ignition to 'see' 2 passes of TDC before any spark develops.

Cold - any excess fuel in the manifold is swallowed.

Hot - any vapours from hot fuel again are swallowed by the motor before ignition commences.

This is how Brad described it to me at S & F.

I admit, there are differences between FI and Carb motors, however it does seem to work awfully well