While driving with circulation occurring you will not see any reductions in temp. The normal CFM flow will have the a larger cooling effect than the reduced temp Thermostat.
At idle on 70' days you will also not see any real differences that cannot fall within normal variances.
At idle on 95+' days there will be a slight reduction .. but only at idle. If you brakeboost for more than a few seconds or start driving the temp reduction will be lost.
The thing to keep in mind is the thing you are *physically* altering is the open/closed state of the thermostat SPRING. IE when it starts flowing water to the rest of the block and when it closes to force the engine to operating temps. that really does nothing in itself to lower temps.
*the tune* is what controls the fans and that ultimately what lowers temps over stock until you floor it, or just start driving or brake boost it. now it does not do any good to have a 100% on fan state that is lower than the thermostat is rated for... that would result in the fan being in high speed mode more than not.
Since the fan is always on and runs a multiple speeds what you are doing is lowering the full on 100% ceiling and forcing the fan to run at higher speeds to try to lower idle temps while not forcing the fans 'full on' under normal conditions.
