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?

[Bitter]

Anything below 235 is safe, 200-220 is pretty normal.

Fix your broken panels and shrouds, add an oil cooler like Bosozoku style.

This post has been edited by Bitter: Sep 14, 2014 - 6:55 PM

[VavAlephVav]

also if you live in a dusty area it never hurts to take a hose and clean the coils for the radiator, condenser, and you intercooler sits in front of all those too.
in the air-conditioning business we have big problems(easy money) with little puffs from Cotton-wood trees blocking up coils. they get down inbetween the layers where you can't always just spray them out without separating one coil from the other and cleaning it out good.

[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...

[Syaoran]

Thanks for the input guys.

Qatar: I'm going by the gauge from the megasquirt which is connected to the oe coolant sensor, not just the cluster gauge.

Currently using a felpro blue MLS gasket.
Turbo isnt water cooled.
I have a preference to using water wetter, I've had really good results in the past with it.
I ordered 25 extra feet of heat wrapping to finish wrapping my manifold and to wrap my downpipe and wastegate dump.

@Bitter: it just worries me because the factory idiot gauge starts climbing up past 205, which leads me to think toyota didnt intend for it to run that hot.

This post has been edited by Syaoran: Sep 20, 2014 - 2:50 PM

[Bitter]

I've seen senders age and read higher than actual temp, verify the temp with a second reading. Also, the OEM gauge itself isn't very well calibrated and it's NOT linear.

[qatar11]

Thanks for the input guys.

Qatar: I'm going by the gauge from the megasquirt which is connected to the oe coolant sensor, not just the cluster gauge.

Currently using a felpro blue MLS gasket.
Turbo isnt water cooled.
I have a preference to using water wetter, I've had really good results in the past with it.
I ordered 25 extra feet of heat wrapping to finish wrapping my manifold and to wrap my downpipe and wastegate dump.

@Bitter: it just worries me because the factory idiot gauge starts climbing up past 205, which leads me to think toyota didnt intend for it to run that hot.

How is the megasquirt calibrated to the OE sender?
If it climbs then stops.... you should be okay... Toyota didn't intend for the engine to run "that hot" because it was designed to last 10 Years and 100K miles - something your home boosted 5SFE isn't trying to do

[Smaay]

have you checked the radiator? do you have a bunch of the fins folded over.

but like everyone posted above, the temps you are seeing are not that bad.

[lagos]

Make sure your thermistor curve is calibrated in MS. On my MS unit i see a consistent 185F when cruising.

[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.

[RavenAegis45]

I wasn't sure of the operating temp either because i noticed mine runs around 190-200 so i wasn't sure if that was normal but seeing this puts my mind at ease