vents in the hood

Super Hauler, yeah it should work, if the vents are big enough, located correctly. In your particular case, very probably will work. I can't estimate how well it will work. And it is possible (though NOT likely) that air flow is not a limiting factor and thus the vents would have no effect.
The PDI Stage 1 certainly adds to the heat load, particularly the inter-cooler. This causes the air entering the radiator to be hotter, but a 5 row radiator should handle that easily.
If you decide to put in the vents, let me know about the results.
Good luck.

 

A couple of things, I would want to check out that tile cleaner idea on an old one first but that could be a benefit, I have washed out a few rads in my time and you start at the top, and with the wand straight at the cores about 1 ft away from it very slowly do a systematic sweep from top to bottom. You can see from the colour what is coming out and get it as clean as possible. First with soap and then rinse and you do have to spend extra time getting the dirt off the bottom sections, that is where the dirt would collect naturally. The beast way is to remove it and have it do at a rad shop, while it is out clean the CAC.
It is amazing also how much heat can be shielded and retained just from a dirty engine, how inefficient dirty coolant is, and how week antifreeze, less than -40 protection makes.
Changing air flow, I have my doughts, removing air flow, for sure seems to me to be counter productive, speeding up the fan blade does not work period, putting on a 8 blade fiber fan, to replace a 6 would, but it would cost you in fuel.
Adding a fuel line return cooler would help with power and a minuscule reduction in overall heat. Just a thought!

 

Yes, yes, cleanliness is extremely important for any heat exchanging surfaces, radiator, exhaust tubing, turbo housing, engine block, heads, valve covers, etc.

Speeding up fans and pumps is usually a bad idea, since most factory cooling systems are biased to the idle speed. Slowing down the water pump can sometimes help the cooling at high rpm, but of course idle cooling will suffer. In general, with a large increase in radiator size, the water pump can be slowed without any bad effects at idle.

SuperHauler has installed a turbo with much higher pressure and no waste gate. Probably about 100 hp increase (20 % to 25%?). This greatly increases the temperatures and total heat load for cooling the engine. If coolant temperature is to remain same as before, then more air must flow thru radiator, over engine components, oil cooler, etc.

After checking some Kenworth data for w900, If he has the largest radiator (1500 sq in) and it is 5 row and everything else is working properly I would have thought the cooling system to be adequate, but his real world experience implies it isn't.
Vents would be something I would avoid if possible. I would look for other ways. But vents can help and if someone wants them then they might as well have the guidance to help them. Different strokes for different folks. I am just trying to help.