Supercharged coolant system woes

[Ian Williams]

Hi Sam, I may be misinterpreting your pictures but I am still not convinced that you have good even water flow though the block then back into and out of the head. You may be cooling part of the engine but getting stagnant water flow and steam pockets in main water jacket around the front cylinders, this will boil forcing steam up throughout the rest of the system. I am even more convinced of this when you say you could not get it properly warm on test runs but it then boiled after 5 laps. I may be completely barking up the wrong tree and as other have suggested you may have too much water flow but all my instinct's and A7 experience suggest otherwise. As Steve suggested it a simple scenario to check simply ad a restrictor in the top hose. But also have a good look at where water enters and exits the block itself, if as I suspect you are using the valve chest water gallery I believe therein lies your problem. I will be extremely interested to learn what is the root cause when you eventually find it.