why two

edbobx · 11-09-2007, 11:43 AM

i was just wondering why the new hemis have two spark plugs per cylinder. i wasn't sure if it was a form of waste spark or what. any feed back would be appreciated

CAT-TECH · 01-28-2008, 08:42 PM

better combustion. More spark means more fuel can be burned, better emissions, and best of all better mpg

Commando · 01-29-2008, 04:41 PM

I also drive a Ford Ranger, its a 4 cylinder and has 2 plugs per cylinder so it is not just Hemis. I was told that the plugs fire at different times so that all the fuel is burned. It gets about 25 mpg, and can accelerate just as well as a 6 cylinder, but comes no where close to my Mopar.

CAT-TECH · 01-29-2008, 05:22 PM

One plug probably fires just after TDC compression and then again after 20-30 degrees of rotation. This is a complete guess on my part but sounds like it makes sense. If someone knows when the plugs really fire that would be much appreciated.

11-09-2007, 11:43 AM	#1 (permalink)
edbobx Junior Member Join Date: Nov 2007 Posts: 1	why two i was just wondering why the new hemis have two spark plugs per cylinder. i wasn't sure if it was a form of waste spark or what. any feed back would be appreciated

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode

01-28-2008, 08:42 PM	#2 (permalink)
CAT-TECH Member Join Date: Jan 2008 Location: Cali Posts: 42	better combustion. More spark means more fuel can be burned, better emissions, and best of all better mpg

01-29-2008, 04:41 PM	#3 (permalink)
Commando Senior Member Join Date: Nov 2007 Location: New Jersey Posts: 153	I also drive a Ford Ranger, its a 4 cylinder and has 2 plugs per cylinder so it is not just Hemis. I was told that the plugs fire at different times so that all the fuel is burned. It gets about 25 mpg, and can accelerate just as well as a 6 cylinder, but comes no where close to my Mopar.

01-29-2008, 05:22 PM	#4 (permalink)
CAT-TECH Member Join Date: Jan 2008 Location: Cali Posts: 42	One plug probably fires just after TDC compression and then again after 20-30 degrees of rotation. This is a complete guess on my part but sounds like it makes sense. If someone knows when the plugs really fire that would be much appreciated.