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So in April I got an OBD UltraGauge to monitor my engine temp to avoid any overheating on my 2014 SFE 89K. I set it up to monitor engine temperature and recently I have noticed that on the highway ~ 70 -75 mph it runs around 210F pretty consistiant. But when I turn on the AC the temp drops to 195 -200 F.

I would of though that with AC on it would run hotter. any ideas why this is , is there an airflow issue that the AC kicks on a fan?

Thanks for any replies
 

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Pretty certain that running the AC forces the high speed setting on the radiator fan to engage.

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My car seems to build boost more linearly when AC is on. I suspect that the AF table has a slightly richer ratio when it is on. I should data log to confirm. Not doing much driving with shelter in place
 

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Turning on the A/C does two things:
1. Opens grill shutters.
2. Engages radiator fan.

I've learned a trick if you want to bring temps down quick; bump the A/C button for less than a second (on/off). This opens grill shutters and enables the fan without engaging the A/C compressor clutch.
 

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Turning on the A/C does two things:
1. Opens grill shutters.
2. Engages radiator fan.

I've learned a trick if you want to bring temps down quick; bump the A/C button for less than a second (on/off). This opens grill shutters and enables the fan without engaging the A/C compressor clutch.
Interesting. I would try that but I removed the grill shutters. As a side note, I have not noticed any dip in MPG without them or any across the board performance gains. I simply was looking to keep the engine bay cooler not only when its running but also after shut down. Anyone else, remove their shutters?
 

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I think most folks wouldn't notice an MPG difference by disabling the shutters, there's negligible aero advantage by itself. If aero was super important they'd have carried over the undertray to the US models. I'm contemplating removing my shutters for the summer months because road temps in Tucson are so damn hot. I think where you'd see MPG gains are in cold climates with quicker warmup times, and not losing so much heat by blasting the front of the block with sub zero temps.

It is interesting you're seeing temps in 210 on the highway with the shutters removed. I'd think there's enough air moving through the radiator at highway speed to maintain thermostat temps (195-200).
 
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