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8.5 MPG on a Stock 5.9 Gasser. Possible to improve MPG?

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  #11  
Old 10-14-2023 | 09:45 AM
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Originally Posted by Isaiah Estrada
Good suggestion, I’m going to “guesstimate” and say that my temp sits at around 180 when the truck is warmed up and stays pretty consistent. I’ve considered a 195 but wasn’t sure if it was worth it or not? ALSO, I’m not even sure if it’s overkill for my truck - but that Hughes airgap intake looks to be pretty promising. I’ve heard there is some MPG’s gained with it as well. I am wondering if it’s worth it to install that intake as well.



Smaller tires it is! I’d like to throw on some 17’s. A 245/65r 17 should be almost equal to the 225/75r 16 so I don’t think it would be an issue. Also good suggestion on those O2 sensors! Will put that on my list of things to do…




I hit OD pretty early it seems. Gradual acceleration I seem to hit OD at like 55 or thereabouts. But if I am accelerating to get on the freeway it kicks in closer to 65/70. I don’t like the big tires. Gonna go down to a size closest to the factory.
Mine shifts into O/D at like 42 mph if I am driving normally.......
 
  #12  
Old 10-14-2023 | 10:37 AM
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What does you tach read in OD doing 60 mph?
 
  #13  
Old 10-14-2023 | 01:29 PM
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Originally Posted by Isaiah Estrada
Good suggestion, I’m going to “guesstimate” and say that my temp sits at around 180 when the truck is warmed up and stays pretty consistent. I’ve considered a 195 but wasn’t sure if it was worth it or not? ALSO, I’m not even sure if it’s overkill for my truck - but that Hughes airgap intake looks to be pretty promising. I’ve heard there is some MPG’s gained with it as well. I am wondering if it’s worth it to install that intake as well.

Definitely change to a 195. Besides using more fuel than necessary, you're also ruining your catalytic converter. The extra fuel is heating it up. In the future, it may melt inside and you'll have to replace it to stay within emissions compliance. That's one thing about Southern Indiana. Nobody bothers you on that. In California though, that isn't the case.
 
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Old 10-14-2023 | 06:46 PM
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Originally Posted by Moparite
What does you tach read in OD doing 60 mph?
Here’s a good visual at 60 on the freeway. This was after an hour drive to Santa Barbara, lots of hills and yet she still ran great.




If I push it up to 72 (65 on the speedo) it sits JUST under 2k. About 1900
 
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Old 10-14-2023 | 08:12 PM
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You need that 195 degree thermostat in addition to either a rear end gearing change (assuming the truck is 2WD - if 4WD, the front and rear gears will need changing to the same ratio) if you're going to keep those tall wheels/tires or swap out to something closer to stock wheel height
 
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Old 10-14-2023 | 09:54 PM
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Originally Posted by HeyYou
Mine shifts into O/D at like 42 mph if I am driving normally.......
Took the truck on an hour long drive and back (2 hrs total, 130 miles) and was able to take better note of the truck’s behavior. So gradually accelerating (no heavy foot) when my speedo shows 50 MPH the RPM’s drop to 1500 and the truck seems to “lose power.” You can still keep accelerating, but it’s VERY slow and unless you punch it to activate the kickdown you won’t get up to speed really fast. If you’re doing a harder acceleration the truck wont go into OD until you let off and in my case, I like to cruise on the freeway about 72 MPH. So when my Speedo shows 65, I’ll let off and OD kicks in. I can keep constant speed but on hills I really have to lean into it to keep up. Again, in OD I’ll have very slow acceleration and unless I punch it and kickdown activates it’ll climb the hill like it should.

Originally Posted by ol' grouch
Definitely change to a 195. Besides using more fuel than necessary, you're also ruining your catalytic converter. The extra fuel is heating it up. In the future, it may melt inside and you'll have to replace it to stay within emissions compliance. That's one thing about Southern Indiana. Nobody bothers you on that. In California though, that isn't the case.

Originally Posted by AtomicDog
You need that 195 degree thermostat in addition to either a rear end gearing change (assuming the truck is 2WD - if 4WD, the front and rear gears will need changing to the same ratio) if you're going to keep those tall wheels/tires or swap out to something closer to stock wheel height

My Ram is a 2WD. Im really stumped on the rear gears now. After decoding my tag, it says 3.21. However, after using my phone’s GPS to take us back home from today’s trip - it told us we were 56 miles away. So I did the mental math and added 56 to the odometer which was 127,834. I got 127,890 - Lo and Behold, we arrived home and the odometer read 127,890. Shouldn’t I technically be showing less miles traveled with the wrong tire size? Dunno if any of that made sense at all. Still; my Speedo is off and per the tire size calculator online - the difference in what my Speedo shows versus how fast I’m actually going is correct. (When I travel 60 I’m really goijg 67 etc etc.) Does this make any sense ? I’m stumped
 
  #17  
Old 10-15-2023 | 02:06 AM
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Originally Posted by Isaiah Estrada
Took the truck on an hour long drive and back (2 hrs total, 130 miles) and was able to take better note of the truck’s behavior. So gradually accelerating (no heavy foot) when my speedo shows 50 MPH the RPM’s drop to 1500 and the truck seems to “lose power.” You can still keep accelerating, but it’s VERY slow and unless you punch it to activate the kickdown you won’t get up to speed really fast. If you’re doing a harder acceleration the truck wont go into OD until you let off and in my case, I like to cruise on the freeway about 72 MPH. So when my Speedo shows 65, I’ll let off and OD kicks in. I can keep constant speed but on hills I really have to lean into it to keep up. Again, in OD I’ll have very slow acceleration and unless I punch it and kickdown activates it’ll climb the hill like it should.







My Ram is a 2WD. Im really stumped on the rear gears now. After decoding my tag, it says 3.21. However, after using my phone’s GPS to take us back home from today’s trip - it told us we were 56 miles away. So I did the mental math and added 56 to the odometer which was 127,834. I got 127,890 - Lo and Behold, we arrived home and the odometer read 127,890. Shouldn’t I technically be showing less miles traveled with the wrong tire size? Dunno if any of that made sense at all. Still; my Speedo is off and per the tire size calculator online - the difference in what my Speedo shows versus how fast I’m actually going is correct. (When I travel 60 I’m really goijg 67 etc etc.) Does this make any sense ? I’m stumped

My speedometer reads high too. I think someone had taller tires and adjusted the sending unit. My temperature gauge was reading where yours is when I tore it down for a major tune up. It never warmed up and had a 195 unit in it. The timing chain had enough slop it never warmed up. It warms up fast now and the one time I had the heater going it was much warmer than last winter.

You can check your chain for slop. It's fairly labor intensive but it will tell you if you need a new chain set. This is easier if you remove the fan shroud. Rotate the engine by hand until the timing mark on the balancer is at TDC. Compression or exhaust, it makes no difference. Pull the distributor cap and mark the location of the rotors with soap stone, paint marker or anything EXCEPT a pencil. The graphite in a pencil will cause shorts and a misfire. Once you have everything set, rote the engine backwards by hand. When the rotor starts to move, stop. Measure how far it went3 or 4 degrees is no big deal.10 degrees though, your chain is worn.

Your temperature gauge should read closer to the center mark around 200 degrees. Timing being off will cause this. I had a '94 Ram 1500 with the V-6 and it went from 15 mpg to 23 on the highway and heat would cook you after a new timing set.
 
  #18  
Old 10-15-2023 | 10:41 AM
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Are you sure you put in a 180 stat and not something lower? I have a 96 and the temp gauge reads different(200 is where your 210 is) and mine will stay just under 200 warmed up with a 180. Yours looks lower than where it should be. You can verify it with a scanner. You are in the same climate zone as i am so you really don't need the 180. I put one in because it won't stay below 200 in the summer. This is because aftermarket radiators have less fins than the original but that's another story. You can fool the pcm by putting in a resister if you relay want to keep the 180.
 
  #19  
Old 10-15-2023 | 11:57 AM
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Originally Posted by Moparite
Are you sure you put in a 180 stat and not something lower? I have a 96 and the temp gauge reads different(200 is where your 210 is) and mine will stay just under 200 warmed up with a 180. Yours looks lower than where it should be. You can verify it with a scanner. You are in the same climate zone as i am so you really don't need the 180. I put one in because it won't stay below 200 in the summer. This is because aftermarket radiators have less fins than the original but that's another story. You can fool the pcm by putting in a resister if you relay want to keep the 180.
I’ve only had the truck 1 month, and don’t know the entire service history on it. It’s possible it could have something even colder than a 180, but I wouldn’t know. It’s never overheated on me, but I do notice it seems to just run cold.
 
  #20  
Old 10-15-2023 | 04:02 PM
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On my 98, the temp gauge read so low, I changed the thermostat just on general principles... Imagine my surprise when the gauge sat in the EXACT same place... THEN I plugged in a scanner to see what the PCM thought engine temp was..... lo and behold, 195......
 



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