5S-FE normal operating temperature Options

[Syaoran]

I think I'm having an issue of either air turbulence at high speeds or some other issue, but the problem manifests itself in the form of increasing coolant temperatures with higher RPMs on the highway.


A little background:
5S-FE rebuilt, .020 over cast pistons
Stock head and components
Fully sequential injection and ignition running on Megasquirt3 with MSX expansion.
Turbocharged with a T3/T4 hybrid running on wastegate pressure (8PSI peak)
2.5" turbo back exhaust with dumped to atmosphere wastegate
2-row aluminum racing radiator
stock radiator cooling fan with swapped condenser fan for a 12" ebay unit


Under 50mph, the radiator fans kick on(the way I have them connected doesn't make just 1 of them turn on) and bring temps down to 183*F no problem, which is when I have them shutting off. It all works just fine. However, past 50mph, my coolant temps rise above 195*F and don't come down unless I let go of the throttle completely and enter deceleration fuel cutoff (DFCO from now on) which pumps fresh air through the engine with no combustion happening. At 60MPH sustained speeds, my coolant rises to 202*F, and the temp gauge starts going up above from halfway.


As I understand it, the coolant temperatures shouldn't be higher than 198*F at the highest point, which is around 94-95*C.

I have 0.9bar (13PSI) radiator cap. Running red coolant with redline water wetter, 2 gallons of coolant or so. Stock water pump.

I believe I'm having one of two issues:

1. Insufficient flow of air through the radiator at high speeds
2. Turbulent air from the fans being on while at high speeds

I'm thinking about making a custom under panel and a custom rad cooling panel. My stock underbody panels are all broken off, so I have none of them, including the one that goes between the bumper and radiator support. I think it's negatively affecting my cooling performance.

Aside from that, I think my underhood temps are way high because of the turbo components. My oil is thinning down to under 10PSI at idle after sustained highway driving as well, normally it ranges from 15-22PSI at idle (shimmed oil pump).


Anybody had a similar experience with insufficient cooling?

[qatar11]

Some questions / observations / suggestions:

200 deg F isn't bad - When we are racing, it stays dead nuts on 200/210 deg F all day without issue (we are running both fans all the time - not great I know)
I would ditch the 2 Row Aluminum Radiator and go with a OEM equivalent Koyo Radiator (see above)
Is the Turbo water cooled?
What Head Gasket are you running?
I'd probably get rid of the Water Wetter... I don't think there is a lot of value add to combining it with OE Coolant.
Get yourself a proper Water Temp gauge... something that isn't dampened so you can see what is really going on
Can you wrap your exhaust with a nice header wrap / ceramic coat?

My guess is you probably don't have any problem at all but you might have some turbulent air and extra heat from that turbo...