The little Hemi that could

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Omar Badran

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Mar 13, 2020
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New Jersey
Ram Year
2017
Engine
5.7
Just wanted to share my experience and the results of my un-scientific experiment.

So I finally did a long tow (well, for me) from Jersey to the finger lakes, about 5-6 hours with stops, with the boat and fam. Pulling about 7k with the fam in the truck with my 1500, 8 spd, 3.92 gears. The thirsty little engine seem to slurp about a quarter tank an hour.

I did a post some time ago asking about the effect on engine temp and engine oil temp that the active shutters had. Lots of folks mentioned that they removed the shutters.

So, on the way up with average air temp in the mid 80's, I thought it was odd how the temps (mostly the oil) would seem to jump up and down (between low 230's and up to 240) when I would be on flat stretch of road with no up hill load....almost like the shutters opening and closing at times. Anyways, I had no issues with temps. The oil got as hot as 250 on the longest uphill running in 6th gear. A couple times I had to drop to 5th and run no higher than 3000 rpms. On the down hill side, temps dropped back down to the upper 230's. All good.

On the way home, with an average air temp in the mid-low 90's, I decided to try the run home with the shutters disabled. I pulled the fuse so they would stay open and of course, the cel eventually came on. In short, the oil temp stayed steady...non of the wacky fluctuations I noticed on the drive up. Once the temp got to the steady point, about 239, it just stayed there. Of course, on the up hills, temps rose to no higher than 249. The one big difference that I noticed in the oil temp behavior is that the rate of temp rise was much slower. For example, started with a temp around 228 and drove almost a half hour of fairly flat terrain until the temp settled out at 239. On the way up, the rate of temp rise was much faster. The same behavior was noticed on the downhills...the oil cooled off way faster and on one of the downhills, the temp dropped under 230.....definitely did not see this on the drive up. The temps dropped down low in time for the next up hill :Big Laugh: With the air temp in the 90's, I was nervous about the up hills, but all went good.

So, in my un-scientific shutter experiment, it seems that the shutters do have some effect on the temps, but it seems more in the rate of temp change rather temps getting too hot when the engine is under load.

In the end, my little 5.7 pulled it off and I really need a 2500 if I'm going to continue and try to do trips like this. And, our government really needs to spend some $$$ and smooth some these roads out :roflsquared:
 

csuder99

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May 28, 2014
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Ram Year
2013
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Hemi 5.7
The primary purpose of the shutters is to improve aerodynamics and fuel economy so the effects on engine temperatures are more a side effect. I used to have a 1500 and your observations match mine. Basically the PCM tries to keep the shutters closed unless engine temperatures warrant opening them.
 

crazykid1994

Senior Member
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Sep 21, 2013
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Florida
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2017
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Hemi 5.7
A little less scientific. More of an observation. I had the express honeycomb grill on my truck originally and removed the ags completely and noticed a slight of drop on my truck when it was stock. I ended up swapping the grill out for a tight mesh grill and actually noticed a slight mpg gain. Nowhere near the original. I think I lost .5mpg average removing the ags and gained .1mpg average with the new grill being less open.
 

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