They are definitely open, if that helps.I'm a big fan of the new STX grills look wise... seams like they would flow way more than the high trim grills as well.
I just washed my truck this morning and my Lariat grille had caught a couple of Pterodactyl-sized insects during my last tow trip.
You'll see more benefit from a radiator or CAC upgrade. Grille is the last thing I would upgrade if looking to improve the overall heating situation.I actually kind of like the blacked out look. Openings are pretty large so might still need to put some minimum “something”, even if also blacked out.
No mesh. Too much flow resistance.
My observation is the OEM cross-hatched grille looks pretty restrictive. Not sure how much additional flow removing it would gain, but I’m thinking maybe 10-15%.
BTW, for those questioning the potential for increasing airflow (eg Ford engineers must have provided enough, and more won’t help), consider that the OEM grilles on these trucks must be designed to flow properly at fairly high speed (80+mph?). So how much do they flow at heavy towing speeds (say 45-65mph), and could they flow more at these lower-than-max speeds? Hmm.
The fans are not doing anything at freeway speeds. Evans cooling even suggested they could be causing poor flow if left on due to turbulance.I think it’s worth considering. In my case, as soon as Mishimoto can get me the radiator (due late Oct), I will be tearing in to the front end anyway. If there is anything reasonable (even simple/cheap) I can do to improve airflow through the grille (reduce pressure drop), I will do that at the same time.
I do think from a fluid flow perspective, each point of pressure drop is cumulative. A reduction of pressure drop across the grille should result in higher pressure at the face of the stack. This should increase flow across the stack.
Pressure at the rear of the stack is probably negative with the fans on high, unless there is more flowing through the stack than the fans can handle. At that point, the pressure would be positive. Either way, the fans will move more air because the increased flow through the stack increase the “head” available to the fans, and they will flow more air just like a pump will flow more water if it has more available suction pressure (head).
Of course, there will be a point of diminishing returns where more flow through the grille will result in very little net flow through the system, because pressure drop through the system will eventually build a pressure bubble in front of the stack until it starts pushing air around rather than allowing it through. I doubt we are at that limit at 44-65mph in high altitude hot/thin air.
I recently ran in to this in my home a/c system where I wasn’t getting enough air through the system to deliver the full cooling capacity of the evaporator/condenser to the living space. I used a manometer to check pressure drops across the return ductwork, filter, evaporator coil, and supply ductwork, and then worked to debottleneck where I could.
The major offender was the air filter which was a high MERV restrictive type. I experimented with several brands/MERVs and found a Honeywell model that was 8 MERV, 4” thick (high surface area) and had a very low pressure drop at the ACFM I needed to get full system capacity. I also changed some of the register settings that were attempting to balance room airflows but cumulatively were restricting the supply ductwork too much.
In the end, I got the ACFM needed at the evaporator to get the full design BTU of the system. Improvement was nearly 20%. So yes, pressure drop at each component had a cumulative impact on the entire airflow through the system.
So at 75-80mph at sea level (dense air) the fans are restricting airflow through the stack? I’m not doubting Evens, just wondering if they have experience/data on this specific design, or are the generalizing ... maybe even wrt much older designs.The fans are not doing anything at freeway speeds. Evans cooling even suggested they could be causing poor flow if left on due to turbulance.
I was discussing the whole ECT thing with my buddy today, who designs and builds turbo upgrades for diesels. We are actually wondering if the advancing of ignition timing actually causes ECT’s to be higher.So at 75-80mph at sea level (dense air) the fans are restricting airflow through the stack? I’m not doubting Evens, just wondering if they have experience/data on this specific design, or are the generalizing ... maybe even wrt much older designs.
Even if the fans are causing pressure drop at highway speeds, all else being equal lower pressure drop through the grill will still help move more air through the system. How much? .1%, 1%? 10%? I don’t know.
What I don’t have, like so many other elements of this whole discussion on curing the overheat issue, is definitive data on this or any of the other potential improvement steps. Perhaps the CAC improvement step is (so far) the only thing I can point to and say definitively, yes, my IAT2 temps are lower and more stable. I measured them. How much will this help manage ECTs? Alas, I don’t know that either.
I guess we all just keep poking around (and spending money) until good things start happening.
I overheated with the stock cac in ALASKA. it was like in the 70s or 80s that day. Granted I was going up a gravel mountain pass that had a "trailers not recommended" sign, but still.I was discussing the whole ECT thing with my buddy today, who designs and builds turbo upgrades for diesels. We are actually wondering if the advancing of ignition timing actually causes ECT’s to be higher.
Retarding ignition timing causes exhaust temps to rise because it spends less time in the cylinders after firing. Advanced timing should cause pressure and temperatures to be higher, but also spend more time in the cylinder, which means the cylinder walls absorb more heat.
I almost wonder if none of us ever upgraded intercoolers, if we would experience overheat as often. I remember on my stock CAC i would be climbing and the truck would slowly run out of power as the IAT2 would head to the high 100’s. By the top of some hills i would have my foot to the floor and the truck would still be slowing down. But it didn’t overheat. The intercooler was the weak link and protected the rest of the engine.
There have been some interesting tests done by folks trying to figure out whether “premium is worth it” on various vehicles. It seems many modern engines do not benefit from premium gas. However, 3.5 eco does by quite a bit. It produces more hp and more torque on premium gas. It must therefore be producing more heat as well (assuming you are using that increased power).While not scientific and completely random, my truck seems to tow cooler, and (not sure how to quantify this) better, using 87 octane fuel. I know Ford recommends premium while towing, but even with 7000lbs attached running through the Rockies, somehow it feels more controlled. Maybe it shifts sooner or something, but with about 15 camping trips this summer, I no longer buy a tank of premium before heading out.
70-80 degrees is still warm (borderline?). What about 20-40 degrees? Maybe nobody camps (tows) at these temps.I overheated with the stock cac in ALASKA. it was like in the 70s or 80s that day. Granted I was going up a gravel mountain pass that had a "trailers not recommended" sign, but still.
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He was probably also going somewhat slow since it was a gravel pass and was relying on the fans to cool the stack. When I went camping outside of Cedar Breaks and had to climb from Parowan to Brian Head, my truck also got hot even though I was only climbing at 25-30mph.70-80 degrees is still warm (borderline?). What about 20-40 degrees? Maybe nobody camps (tows) at these temps.
I know that road well. Some tight turns and very steep grades, especially toward the top. Two very tight switchbacks just before the top. Elevation around 11000 at the top, so very thin air.He was probably also going somewhat slow since it was a gravel pass and was relying on the fans to cool the stack. When I went camping outside of Cedar Breaks and had to climb from Parowan to Brian Head, my truck also got hot even though I was only climbing at 25-30mph.