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?

[Syaoran]

Yes, the sensor is properly calibrated. Thanks for the suggestion.

Apparently, the 5s doesn't like running at 15.5-16 with timing advanced 30* in my 98*-100*F weather.

I lowered the cruise AFR down to 15.0 with timing at 30* or so and it helped the temps stay at around 185*F.