So update.
Went back to brands, although the cooling was much better it was far from ideal, i can now get 3 hot laps in a row and then the coolant would hit 100c so i would then back off for 2 laps and go again.
This led to far more seat time and as a result another new PB! same boost level of 1.2bar but i shaved 0.8 secs of the last PB so thats good.
New PB stands at 54.3, although that would be good enough to put me 9th in UK Time Attack (for the FWD class) the cars got more in it as it stands, id say closer to a 53.5 without changing anything.
Heres the video, 1st lap a 54.3 then the 2nd lap is 54.4
I know where i need to be quicker/more committed so the aim is to nail those areas next time out and hopefully take another PB.
We didnt leave brands unscathed though, ive had a sticky rear brake caliper for awhile now, this finally caught up with me as i boiled the fluid in thay corner late in the day, the cooling is still an issue also.
So this week ive replaced both rear calipers with refurbished ones, replaced all the brake fluid, new spark plugs and engine oil as they where well over due.
Now onto my cooling issue, thinking logically(well trying to atleast) i can only think of 3 things that could cause this issue
Poor airflow
Poor coolant flow
Poorly engine
After the last round of tests im not willing to throw the towel in on the engine, it pulls well(as you can see) compression is good, doesnt use water or over pressurise the system, so park that for now.
This leaves me airflow or coolant flow. now my radiator, although large isnt the best quality, is a twin pass radiator but its only a single core. This means that it cant flow as much coolant through it and its got to squeeze all the coolant through the rad one way, then back the other way. Youd think that the coolant having to travel the length of the rad twice would be a good thing right? Well not if the coolant flow slows down too much....
So ive gone baller style(more accurately desperate style) and bought a rywire tuck radiator, these radiators are the same size as my current rad, still twin pass but they are dual core vs my rads single core. Im hoping this will allow somewhere near twice the coolant flow through the rad and thus fix my problem.
As ever, time will tell!