Is the GT3 engine a twin-plug or single-plug design? If twin, do both plugs fire simultaneously?

Thanks.

-Karl

 

Single plug.

 

I think the normally aspirated 993 was the last twin-plug Porsche street car. Yes, all Porsche twin-plugs fire simultaneously, AFAIK. It allows the use of a higher compression ratio without detonation.

I don't know why they got rid of that - maybe it's not needed with the new 4-valve heads on the water-cooled motors. The compression ratio on the GT3 is certainly no slouch (higher than the twin-plug 993).

 

The improved head cooling in the water cooled cars eliminate the need for twin plug.

 

If Iremeber right the 993 fired at diffrent times not at the same time, as an attempt to reduce emmissions on the air cooled engine, Changing to water cooled engines that maintain a much more consitent teperature its much easier to control emissions and does not require dual plugs

 

All you have to do is look at the 2 heads side by side and you will immediately see why. With the 2 valve head, the spark plug is way over to one side of the combustion chamber, and it takes forever for the flame front to get across the cylinder. That's why they put the second spark plug on the opposite side, to cut that time in half. The 4 valve head has the spark plug directly in the center of the combustion chamber, and has the shortest distance to ignite the total mixture, in a uniformly radial pattern. Can't get any better than that.

 

993 turbos dont have dual plugs.................

 

That's why I said the naturally aspirated 993 was the last one