Your intake air temps will be lower with the mechanical fan in place. It keeps air flowing over the intercooler at all times, without it your intercooler will heat soak, particularly when stopped or in stop-and-go traffic.

Heat soak is when the intercooler can't dissipate the heat that it absorbs from the turbo fast enough. When an intercooler can't cool the charge air by removing the heat from it, it loses its effectiveness.

Being in Minnesota in the middle of the continent, we have very extreme hot and cold temps and so we run the mechanical fan in the summer but remove it in the winter.

Agree with weeks, you can at least put an efan there and start it manually when it's hot and driving stop and go.

I understand it is substantially less air, but wouldn't the electric fan accomplish limited intercooler heat exchange? Oh, and the climate here is similar in summer, but less ice-age in winter (I live in MN, WI until age 10).

At idle temps, the turbo is not adding anything, either. I am not sure of the spin-up rpm on the turbo, but the butt-dyno seems to recall something in the 1500 rpm range. Right-ish?

If memory serves, the stock electric fan only turns on when coolant temp hits 203F. The mechanical fan is spinning all the time.

The intercooler absolutely will heat soak even at idle with 0 boost generated by the turbocharger. Exhaust gasses are flowing through the turbocharger, heating it up; your turbo is sucking air where its heated by the turbocharger, travels through the intercooler where heat is allowed to dissipate. If there is no airflow across the intercooler, temps will climb and it will heat soak until you start moving, airflow increases and your intake temps stabilize.

I have been monitoring intake temps for 6-7 months with a thermocouple unit, both with and without mechanical fan. Generally: on a mild day like today (70F) intake temps with no mechanical fan would exceed 50-75F above ambient at idle. With a mechanical fan intake temps are pretty stable, hovering around 10-20F above ambient.

Thermorex: I apologize for not clarifying: there already is a factory electric fan in there. In addition to the stock e-fan, is there a definite need for the mechanical fan, if not doing long-distance towing in slow traffic?

Thanks!

I too removed my clutch fan when I did my t-belt about 3 years ago.
No over heating problems.
While driving, Intake air temps can be 20-30 degrees above ambient. But while stopped it can get higher.
The main drawback here is that the fan will only turn on under one of these two conditions:
1. A/C is on. And with the A/C on that adds more heat.
2. Engine temp hits 205 F.
If you are slowly climbing a steep hill in the middle of summer, it might seem like a good idea to turn the A/C off to reduce the heat through the radiator. But then again, A/C off = no fan until 205 degrees. And you WILL 205 really quick when climbing a hill in summertime. At that point the electric fan may not be enough to bring engine temps back down.

I am going to work on a simple modification that will allow manual control of the fan. The way it will work is that the fan will turn on low with the ignition key on and will stay on low while the engine is running. A toggle switch on the dash will allow you to switch between low and high fan speeds.
I've done some testing and it works. I just gotta figure out a way to run the wiring and mount the switch on the dash.

But first I have to get my engine back together.

Note: my intake air temps were taken from the MAP sensor using Torque Pro.

It's not that you'll break the car without a fan for intercooler, but won't be as efficient.

Other than money reasons, is there anything else that keeps you from installing a new separate puller fan? I'd say it's easier to leave the car wiring as it is and add your own efan to replace the stock viscous. Plus there is less risk if one of them breaks.

... but I had to ditch the stock pusher and go with 2 7 inch fans due to fitment issues...

I'd like to have the option to keep the viscous and just manually adjust the clutch...