Under Bonnet / Hood Insulation

[Roger Morrall]

I fail to understand why one might wish to insulate the underneath of the bonnet and keep even more heat in. The usual plaintiff V8 cry is connected with getting rid of the heat, not keeping it in. Also bear in mind that the hotter the air the engine is ingesting the thinner it is so the less power is available to you. I believe you’d get something like 20% less ooomph at 90C as compared to 20C. I’d be most interested to know if I’ve misunderstood some fundamental point.