Just drive with no hood on. I see plenty of cars around the city with no hoods.

Start with replacing some of the internals first. Silicone , intake radiator and wiring hoses. This will protect the car from the heat that's exerted. Ceramic coated stillen header will help promote keeping things cooler. Then you might want to consider? (Depending on yyour drive style or if you are force feeding your car) a thermostat. An oil and power steering cooler will help keep things kool. Then finally, one of these slotted hoods.

Don't do the thermostat all it will do is throw CEL:shakes head:

why would a thermostat change cause a CEL?
it might not be too helpful in cooler months but i've been contemplating a thermostat swap for mine for a while. other than that, i would like to take control over the fans and crank them on at a lower coolant temp but that requires uprev.

my quest to find a coolant temp sensor that had different scaling was futile also.
even if i found a suitable one, the sensor is in a very awkward spot to reach. easier to wire up a switch to kick the relays on

Because it will take the car too long to warm up and the water temps will fall too quickly and you'll get a CEL

:iagree:
The car has certain presets built in, you can "overcool" the car and cause a CEL if it does not warm up fast enough.

On the venting side:
-Vented hood
-Vented fender liner (GTM sells a prefabbed one but you can DIY it)
-Undershroud
-Better heat management (Wrapping intake pipes, headers, etc)

Cooling:
-Tune with fan speed adjustment
-Radiator upgrade
-Radiator fan upgrade
-Oil cooler
-Radiator fluid swap (doing a blend of antifreeze & water)

Since the back of the hood and windshield is a high pressure area, wouldn't removing the seals there or raising the back of the hood cause air to be forced under the back of the hood at speed? Kind of like a cowl induction hood on a domestic? Airflow coming in that way would interfere with the air exiting the back of the radiator. I'm all for lowering underhood temps, but I'm not sure tha's going to work as planned. I would expect it to have some positive effect when stopped, just not at speed.

Right now the next items I've got to do for heat management is venting the fender liners, putting in a slightly lower temp thermostat, and going to a different mix of antifreeze and water. A vented hood may happen down the line, but I'm not sold on that on a daily driver.

The ECM takes a look at your ECT's and your IATs to determine if your thermostat is doing what it should. If this check fails it will trip a code.

Well you might get a good report here soon...if something happens for me. ;)
On the hood seals, it would depend on the air pressure under the hood. Like the GT500 this is true, that is why they vent from the front because air pressure is pushed forward to that point and is released from there. The Z might push air backwards possibly or down even while driving which means the best venting is the vented hoods and under the car.

Need someone to run some pressure tests on a stock hood and determine airflow during idle, slow driving, WOT, etc.

Or just tape a bunch of 1" pieces for yarn all over the area and see which way they move.

Go to a 25/75 mix of coolant/water instead of the typical 50/50. This can easily drop coolant temps 10-15 degrees.

If I did just a basic flush of the system, meaning there is still some in the system somewhere. How much water v coolant you think?

That's next on my list. Even with the CSF radiator, lowered fan temps and an oil cooler, it gets a little hot in traffic if I've been beating on the car earlier and it's over 100 degrees. I'll see the temp gauge move up 1-2 dots.

The back of the hood typically is a high pressure area and raising it is a double negative. Not only does it disturb proper flow through the radiator(s), it lets heat into the cabin.

The belly pan isn't just just for splash protection, it acts to aid flow through the radiators, especially helpful when there are two or three that air has to flow through.

That's exactly what I thought.