In Nigeria over 40c that's crazy! The only thing different about the Coupe that sets my mind racing is the vast amount of extra distance the pump has to move the water/coolant. From your description I imagine your twinni used a standard-ish mini set-up in the front thus only having very short pipes connecting the block/head to the rad set-up.

I do like the idea of simplicity and in a perfect world would really just want to run an extra radiator somewhere else on the car but don't know if that would actually benefit the cooling or be a hinderance.

I like the idea of setting it up to operate after the thermostat has opened but if the car is getting hot quickly anyway would consider removing the thermostat completely.

Hi Runk,
The Twinny front set is standard apart from the heater core mounted behind the grill instead of over my feet
My old 1430 Cox used a ducted front mounted rad, again with big impellor pump and still used a thermostat, the only thing that overheated was the driver with those hot pipes in the center tunnel, Whooo I can still remeber how I used to melt on hot days, the Cox also had a ducted oil cooler taking air from the right side above the wheel arch and exiting through a mesh gill in the top of the engine cover