Ouch. First off I hold you in high regard and really appreciate your defense of me on the Moparts forum.
My critical thinking now requires me to disagree.
Having done TIG welding on aluminum and acknowledging the heat required, there seems to me a large difference between TIG welding on aluminum and hot gas expansion in an aluminum combustion chamber. Electrical arcs and expanding hot gasses could have a very different energy exchange rate with aluminum.
I believe the high frequency used in the AC TIG arc breaks down the resistance in the air gap between the tungsten electrode and the aluminum to begin the arc and the transfer of the heat therein.
In a combustion chamber I also believe there may be a cooler air gap boundary that the heat of the gas has to compress and penetrate before getting to the aluminum, and therefor retards the transfer of the heat to the aluminum owing to the speed of the combustion process in the internal combustion engine. This may be similar to the dead air boundary in the port of a cylinder head.
Theory is one thing, scientific (maybe dyno?) tests are another. Though I have done no dyno tests on aluminum vs iron, the only tests I have ever read of have not shown a loss of energy, read horsepower, in switching from iron to aluminum heads. The testers used iron and aluminum heads with the same combustion chamber shapes and similar air flows, and in each case found the aluminum head to produce no loss but slightly more horsepower. They then claimed they didn't believe their own results were accurate. Now there is some critical thinking!
Do you have detonation or horsepower tests that show otherwise? Because I would love to see them!
