Aluminum heads
This just isn't true Rob. Think about it. The time it takes for detonation to occur happens so fast that the metallic structure of the head has zero influence on it.
Agreed.
Somewhere on here I typed out several AJ length posts explaining the cooling system and how it affects CR much more than aluminum or cast iron heads. I had to type so much my hands swelled up and I couldn't type anymore.
If anyone knows where that is, move it up and I'll finish it.
If ya can find it, I’d enjoy the read.
But fact is aluminum will cool faster than a factory iron head. Heat both up in your oven and stand by with a heat gun.
That I think we can agree on.
Now the heads, the cooling liquid (not the entire system)
And the path it takes around in the head is the other story in controlling head and thereby to an extent, cylinder temps. By this, we will assume the air fuel mixture is perfect. And when it’s off, the story changes and the topic swings. We can get to that later.
Agreed?
The rate of change of temperature from cruise temp to detonation temp is so fast that there is no metal I know of that can affect detonation.
Agreed
That's why I harp on the cooling system so much. Slow turning, low flow water pumps, junky assed electric fans, cramped shrouds and more make it nearly impossible to control detonation rather than head material.
Absolutely!
I could actually run a 160 thermostat and my cooling system would keep the engine at 160 even on a 100 degree day. If I take the Thermostat out, I doubt I could get 130 degrees into the engine on a 100 degree day.
That's one reason I'm running 11:1 on iron heads on pump gas with full timing. Coolant temp control and flow are WAY more critical than an aluminum head is.
Let’s take a step back and say that we are testing two identical heads with the exception of the metal used. These heads are placed on two identical engines. The compression ratio is 12-1. Fuel is 93 octane, no additives.
The test is to see which head has detonation issue first and there only change is a camshaft from “OFF THE SHELF” (Pick any manufacturer but just one.)
Who has problems first and why?
