Originally Posted By: GOPHER FREAK
So far the best I've seen by checking every fill against miles traveled is 23 at 75mph. I've really only been on the interstate since I've had it. My overhead says anywhere from 25-27 at 60, but I don't have enough miles at that speed and that speed only to really tell yet. But my overhead is fairly accurate at 75mph (it reads 24) so I'm hopeful.
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You have a huge, massive, freak of nature. Don't touch or do a thing different! Not being funny. I am dead serious.
Anyone exceeding 20-21 MPG with a HEMI Ram 2WD( MDS equipped or otherwise ) is so far above the norm it is not funny let alone a 4WD. It usually takes some kind of handheld tuning device like Superchips with a fuel economy tune to boot to see that kind of MPG as well. The fact you say you are seeing this at 75 MPH out of a 4WD no less has me going
???
99.99999% of HEMI Ram owners who go that fast, even with 3.55 gears to keep RPM's down, see 16-17 MPG at best and usually it is more like 14-15 MPG. At 60 MPH in CC on a flat road you should be seeing anywhere from 18-20 MPG tops from a HEMI Ram w/ MDS( or without because actually MDS does nothing noticeable for the 06-08 Ram - on the Durango and cars it does - not so much the 06-08 Ram ).
I had an 04 Ram 1500 QC 4WD 5.7L HEMI( non MDS )w/ 17's and 3.55's plus dual exhaust, a CAI, synthetics all around, and a hard tonneau. The best MPG I ever saw was 20.2 MPG all highway hand calculated( overhead was around 24'ish ). I never broke 19 MPG other than that one time with perfect conditions all highway. Average MPG was 14-15 MPG.
I now have an 08 Ram 1500 QC 4WD 5.7L HEMI ( MDS )w/ 20's and 3.92's plus dual exhaust, synthetic oil( gear oil and tranny/t-case to come ), and a hard tonneau. Best all highway MPG to date has been 18.9 MPG( showed 21.2 on overhead )with the CC set at 60 MPH( go higher and MPG plummets! ). The average MPG has been around 13.5-14 MPG hand calculated( overhead runs 15-16'ish ). I attribute the lower MPG results vs the 04 to the lower gear ratio and larger/heavier tires.
I do think I can break 20 MPG( barely - hand calculated )with this truck just like the 04. However, 23, 24, 26+ MPG is not happening. That best to date 18.9 MPG came with just 1500 miles on the truck, no exhaust or tonneau, and it was like 8 degrees F out. It was a trip last January from NH to NY. The engine is now broken in, I have some items that help performance/MPG, plus I could test it in warmer temps. Should be good for 1+ MPG.
To see the kind of mileage you are reporting from a HEMI Ram( even a regular cab, short bed, 2WD, stripped down version never mind a 4WD )is really, REALLY, hard to believe. I am not calling you a liar and don't mean it to sound that way. I am a HUGE HEMI Ram guy however and I am very active on the Dodge truck/HEMI forums. Your results are so far from the norm it has me wondering if I am missing something in your post like you are basing this solely on the overhead or something other than actual hand calculated data( ie; total miles driven divided by the exact amount of fuel purchased to FILL the tank - if tank was not full to start you have no idea of the accurate mileage )? Just does not seem possible.
Also, if you overhead console is accurate as far as your hand calculated miles vs the AVG MPG it shows you really have a freek because the Ram overhead console is notoriously inaccurate. Anywhere from 1.5-4 MPG+ off for 99.99999% of owners and as a rule the higher the AVG MPG it shows you the more inaccurate it is when compared to hand calculated figures. Mine runs 2 +/- MPG off as a rule but have had it 5 MPG off!
So you are seeing a hand calculated 23 MPG @ 75 MPH from a 4WD HEMI Ram w/ MDS and the overhead shows 24 MPG???
Call Dodge and have them buy the truck from you to find out what is different about it so they can use that info to help others.
As to your actual oil questions.
Yes, stick with a 20 weight. You can run 0W-20 in the cold temps and it will not effect MDS. What matters is the 20 weight. As to brand. As said above don't alter or touch a thing. Find out what brand the previous owner used and go with that changed at 6K. I would not do ANYTHING to that truck other than put gas in and change the oil using that brand and weight at 6K based on those MPG numbers. Just unbelievable so don't mess with it.
There isn't another Ram owner out there that can touch those numbers if they arre being 100% honest and accurate. Not even a stripped 2WD RC. Heck you couldn't get 24 MPG out of a HEMI Ram if it was towed on a flat bed! They suck gas down even when turned off.