Head Material Affects Power?

[BrettTheThreat]

Just something I noticed while noodling around in the sandbox trying to make an uber-Flatplane V8. I managed 1850 with aluminum heads and changing to Cast Iron boosts me to 1859.. Is this supposed to happen?

[Daffyflyer]

Yup! Whilst slightly lighter, Aluminium heads lose a tiny bit more heat, thus make a tiny bit less power. Its such a small effect that you only really notice it when you're making 1000hp+ though.

[BrettTheThreat]

That is the most interesting thing I have learned in a very long time. Thank you!

[MAC_HATER]

yeah its very interesting!

although Running Cast iron bits would negate the extra power by simply being heavier so it wouldn't work out to extra performance at the 0-100kmh tests id think

[Daffyflyer]

Yeah, you'd have to be making a truly spectacular amount of power from a small engine for the power gain to be worth the weight gain

[oppositelock]

I could be wrong, but I was under the impression that aluminum heads were less prone to detonation, thus allowing higher compression ratios and more power compared to iron. Also a bit off topic, but I noticed using iron blocks with aluminum heads causes MTTF to plummet versus all iron or all aluminium motors. I know they theoretically have different rates of expansion which can cause head gasket issues, for example, but I find this unnecessarily exaggerated. It literally cuts engine life almost in half.

[Daffyflyer]

The MTTF penalty should apply quite hard for approx pre 1970s engines, but its not quite balanced the way we want yet.