Firing sequence - LT5

[secondchance]

I remember a typical early Chevy V8 (I believe LT5 also) has firing sequence of 1-8-4-3-6-5-7-2. Also recall distributor cap had 8 posts - one per cylinder. Meaning cylinders were firing one at a time. With LT5s having one coil per 2 cylinders, I presume one coil handles 1 & 8, 4 &3 and so on. Is this correct? Does this mean these pairs are fired simultaneously?
I just got curious.

[-=Jeff=-]

yes pairs fire simultaneously

I forget the Coil Pairs, but as one is in power stroke the other firing is exhaust stroke I believe

Firing order is still 1-8-4-3-6-5-7-2

[Paul Workman]

Originally Posted by secondchance

I remember a typical early Chevy V8 (I believe LT5 also) has firing sequence of 1-8-4-3-6-5-7-2. Also recall distributor cap had 8 posts - one per cylinder. Meaning cylinders were firing one at a time. With LT5s having one coil per 2 cylinders, I presume one coil handles 1 & 8, 4 &3 and so on. Is this correct? Does this mean these pairs are fired simultaneously?
I just got curious.

It's called a "waste spark" system. Cylinders are twinned, but only one at a time is in compression cycle when the spark arrives.

Just a point of interest: Because current flows in a loop through the block, coil and plug wires/plugs, the current is the same through both spark gaps. However, due to the much higher compression air pressure in the cylinder about to fire, the gap resistance to flow is much higher, resulting in the heat generated in the spark to be proportionately higher than that in the waste spark cylinder. In other words, the majority of the energy expended in the circuit is concentrated in the compression cylinder, resulting in very little actual "waste", really.

FWIW,

P.

[secondchance]

Hah! So what I am hearing is that one of the cylinder (of the pair) when sparked is in ehaust stroke and really not in need of a spark. Basically cylinders are fired individually. Interesting...