Speciale water temperature - how hot is too hot?

Hi Phil. Thank you for this input.

I go back and forth from the mountains in Utah to the beach in California. I couldn't understand why I was seeing 10-20 degree difference in engine temperature up here versus down there. When I first posted my concerns about water temperature, I mentioned that I had been driving in the mountains but I didn't think the altitude per se had anything to do with it. Many fchatters told me the temperatures I was concerned about were still in the "high normal" range so not to worry. Okay. But it was still nagging at me. Why? Hmmm. I think the info I found about radiators not cooling as efficiently at high altutudes is probably the answer.

Phil, I guess you and I are the only guys on fchat who spend a lot of time at 7,000+ feet

 

It seems to make sense that the thinner air flowing through the radiators at high altitudes has less capacity to take heat away. And the slower you drive the worse it gets.

I liked your example of putting your hand out the window at altitude versus sea level. All that lost RAM air pressure at altitude is a loss in the capacity of the air to carry heat away from the radiators. Hence, the engine runs hotter at altitude.

BTW, I read that a NA engine loses about 3% HP per thousand feet (my butt dyno concurs). I assumed a turbocharged engine wouldn't lose any (or very little) HP at altitude. BUT I was wrong. Apparently even turbocharged engines lose HP at altitude, but the information I read used a rule of thumb of 1.5% per thousand feet.

I'm definitely not a science type (more bean counter), so if anything I'm saying is inaccurate or if I'm drawing wrong conclusions I'm hoping that someone more knowledgeable than myself will will jump in and clear things up

 

I'm at 8,400 feet. Takes me a couple weeks to catch my breath everytime we come up here.

So far as I know, you live at the highest altitude of all fchatters

 

I'm guestimating that at 8,000 feet our radiators are about 25 percent less effective.

Unless someone explains why I'm wrong, I'm gong to finally put this mystery to rest. I'm satisfied that there are technical reasons (physics) that explain why my Speciale runs noticeably hotter at 7,000-8,000 feet than it does at sea level.

 

I asked one of the mechanics that run 458 Challenge cars if 220 degrees was too hot. He said 220 is fine, but 240 is too hot. But I understand your question. Everything is fine at 239, but suddenly at 240 it causes damage? I guess a practical answer would be to assume damage will occur over 240 degrees so take steps to reduce engine temperature before you get to 240.