I calc'd this like 4 or 5 years ago. Something around 5,800 CFM at 80% IIRC. I've seen 8 blade fans on some larger rigs that move 9,500 CFM Nothing beats the factory set up with a modified clutch.
For best cooling:
- Radiator shroud needs to be in good condition and sealed around the edges
- Fan clutch should be modified with 10,000 or 20,000 CST oil (I also run mine slightly advanced)
- Belts need to be in good shape and tensioned correctly, at the higher RPM and load they can slip so I run my belts TIGHT
- Run a leaner coolant mixture than 50/50, water has a much higher thermal capacity (ability to carry and transfer heat) than Glycol (coolant). I run a 70% Water / 30% Coolant + Water Weter (surface tension surfactant that prevents bubbles from forming, this improves the heat transfer efficiency)
- If you do this you need to be cognizant of your coolants freezing point, and adjust it in the fall to stay below your winter temps
- Gently hose your Radiator and fan clutch often to remove dirt, mud, dust
- Make sure your radiator cap is good
On a trip last year to moab I was driving I-70 from Georgetown to the Eisenhower tunnel, this is a 7-8% grade for about 11 miles, starting at 8,500' and ending at over 11,000' above sea level. My rig was loaded out to about 7,000lbs, and it was an 85°F summer afternoon. From Georgetown to the tunnel I had the throttle pinned, not lifting once. I watched the temp (measured at the head and block discharge pipe) climb to 185°F, then the fan began to roar as the clutch engaged, over the next mile I watched the rig COOL ITSELF DOWN to 175°F while I was still holding the pedal to the floor. Pretty wild.
Now I don't have an AC Condenser in front of the radiator, but I do have a high clearance bumper and winch which disturbs airflow. And the radiator isn't anything fancy, just a rockauto TYC 1918.
That's a lot of unnecessary complication for a simple problem. IMO the OP should revert to stock, advance a new Blue Clutch, and change out its oil with 10,000 or 20,000 CST weight. there's plenty of great write-ups here. You can always add the fans to the front of the AC condenser as pushers (but i think people really only do this to help the AC star cold)
)! That helped too. Especially for cooling off a bit after I park.
. So I got AC, cause you know the Lexus ain't a land cruiser and it's fancy. Real fancy on the badges at least. still looks like the poor man's land cruiser everywhere else tho =)
