Originally Posted by Precision (Post 4890702)

I never said Sterling was doing anything wrong. Its more about the efficiency of the cylinder head and no parasitic loss.

And those Sterlings were $65K for the pair from Dave. I have way more than that in my LS engines. I’m simply sharing performance data I have measured. I’m not saying one is better than other.

The PSI engines are cooler IMO. They were so obnoxious they knocked the lights down in the dyno. They looked cool, sounded cool, and screamed power boat.

Originally Posted by ICDEDPPL (Post 4890707)

Correct me if I`m wrong but at the end of the day an engine is a pump, you can make a more efficient pump but the basic principle is the same. Expansion of air and fuel is what creates the force to move that piston down.
It`s cylinder pressure that makes power. The more cylinder pressure the more chances of detonation and pre ignition . Generally a smaller displacement engine needs to operate at higher cylinder pressures to produce the same power as a larger displacement engine since it needs to extract more energy from each combustion event to compensate for its smaller size. Larger displacement engines will have higher tq (important in boats) at lower rpms and they do not need to make as much cylinder pressure to make the same power and the octane requirements are lower .
There is no replacement for displacement, thats not a slogan that`s just physics.
You better have some high octane to make 1350hp in an endurance engine especially if it`s a small block.
The LS is not some magic engine that defies physics.

Originally Posted by Precision (Post 4890712)

The only difference here is the LS engine would extract a little more power out of the fuel mixture per combustion cycle than the big block. But, that little bit of power won’t make a big difference in a heavy vee.

Originally Posted by hogie roll (Post 4890713)

You keep saying that, I’m not sure why you think an LS has some 15% VE advantage over a BBC that has a modern aftermarket head with a good combustion chamber.

Originally Posted by Precision (Post 4890714)

The LS testing I have done to date has been mostly LS7 12* heads. And the BBC testing has been Mercury 525 (Edelbrock Performer RPM).

Originally Posted by hogie roll (Post 4890718)

How is that even a surprise? The 525 is old stuff with garbage heads, intake, and no compression.

You could bring the VE up 5% just by making the CR 10/1.

Originally Posted by Precision (Post 4890714)

I have yet to test the Big Chief stuff I’m working on currently.

Originally Posted by ICDEDPPL (Post 4890707)

Correct me if I`m wrong but at the end of the day an engine is a pump, you can make a more efficient pump but the basic principle is the same. Expansion of air and fuel is what creates the force to move that piston down.
It`s cylinder pressure that makes power. The more cylinder pressure the more chances of detonation and pre ignition . Generally a smaller displacement engine needs to operate at higher cylinder pressures to produce the same power as a larger displacement engine since it needs to extract more energy from each combustion event to compensate for its smaller size. Larger displacement engines will have higher tq (important in boats) at lower rpms and they do not need to make as much cylinder pressure to make the same power and the octane requirements are lower .
There is no replacement for displacement, thats not a slogan that`s just physics.
You better have some high octane to make 1350hp in an endurance engine especially if it`s a small block.
The LS is not some magic engine that defies physics.

Originally Posted by hogie roll (Post 4890713)

You keep saying that, I’m not sure why you think an LS has some 15% VE advantage over a BBC that has a modern aftermarket head with a good combustion chamber.