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Everything posted by hertfordnc

  1. This is just a feasability question. I have this great running 2003 Dodge 3500 cummins, NV5600. Pretty much my dream truck. I don't need all that power but it pulls my camper with ease and makes a great daily driver. But it is BEAT TO CRAP, and it's 2WD. So i am on the lookout for a parts truck to scavenge all cosmetic stuff it needs to not be ugly. But then i thought, what if i found a good truck to put the drive train in? A 10 year-old gasser with a blown motor could probably be had pretty cheap. Would there be crazy wire harness problems and welded frame parts, or did they make the truck ready for either engine?
  2. Just back form a 1500 mile trip in the 6000 lb family car (2003 dually 4 door) and I have an obeservation about the clutch fan: The truck temp hovers at 200 degrees and the clutch fan sometimes kicks in when I'm cruising at 60+ it goes off after a few minutes. Assuming this is normal that means that 60 mph does not deliver enough air to keep the engine cool (outside temp around 100 F) Every square foot of open grille equals 5000 CFM at 60 MPH so an electric fan would have to move north of 10,000-15,000 CFM to equal that, right? Oh yeah, i got 19.9 miles on the best 350 leg of the trip (not hurried, rested, no traffic) I got 18-19 on the rest of hte trip.
  3. About that ideal range of 1600-1900 RPMs, which side do I err on? I spend a lot of time on 50-55 mph two-lane country roads. so I'm at 1970 RPMS in 5th at 50, 2170 RPMs at 55. But I'm at 1500 RPMs in 6th. I'm leaning toward staying in 5th longer. What do you think? thanks Dave
  4. Moses, THanks so much for your advice. I've been working hard at shifting in your suggested RPM range and getting pretty good results. Topped off the tank, drove 100 miles or so, computer said 21.7 actual was 19.9; topped it off again and now the computer is holding around 24.0 . My other car is a hybrid so I'm pretty familiar with the issues of driving technique but the explanation of torque range really brings it all together. WHat about performace upgrades that do not dump more fuel in the can? Bigger exhaust, cold air intake, etc. People usually do those thing to shred tires and scare small animals and then they lie about the the MPG. But do you think those upgrades would actually help if I did not want to shred tires? thanks
  5. But aren't we talking about the same thing? It was the use of the 3.42 gears on the newer trucks that got me thinking about this. I'm not as co ncerned with towing mileage as I won't be towing that often. The other five gears would still give me plenty of choices. What am I missing?
  6. I think part of the advantage some people get from electric fans is simply settling for less cooling. For vehicles that are not run at the limits of their capability eliminating the parisitc drag and replacing the cooling with a less capable fan will result in some gians, right? What about dropping the final drive to 3.42? I know, crazy, but follow my particular logic; I know i have 3.73 gears now. Where I live and where i would do my daily driving is pretty flat. The NV5600 give me lots of choices to match RPM as needed, I could start using 1st and 2nd more. This is more truck than i need. It happend to be a very good deal, it's cosmetially bad and mechanically good (far as I can tell) But it's a lot of truck. I would have chosen a 2500 or Ford F250 or perhaps a Diesel suburban. But I wound up with this truck for just over $4K so if it works out I will modifiy to suit my needs and I don't care if i degrade it's overall capability. My camper weighs 7200 lb. With 3.73 gears this truck is rated at 13,800 lb. With stock tires I beleive 3.42 gears would turn 1900 RPMs at 72 MPH. I see people discussing the idea but I have not seen anyone post results. Your thoughts? Thanks
  7. Hi, I found this thread in a google search on Cummins MPG and joined this forum specifically to get in on this discussion. I think I read everything above a couple times. The idea of running at peak torque makes so much sense I can't believe I have never seen it anywhere before. I just bought a 2003 Dodge 3500 with NV5600. The goal is to make it an efficient daily driver and trailer puller. We have a 7000 lb vintage camper so it's no problem for the truck. I am most interested in fuel efficiency when running empty. My daily commute is 26 miles with just a few stops and turns on 55 MPH back roads. I put on a set of used matching tires sized to the door sticker (235/80/17) The MPG you describe above, is that calculated at fill up or based on the computer? So many people on these forums talk about mileage without making that clear. Do you think switching to single wheels would help? There is a lot of un-informed debate about that. What about modifying the fan? Again, in my reading I find a lot of misguided uninformed debate. I know electric fans are theoretically more efficient, but the debate over making it work on a fully laden Dodge 3500 on a 7% grade is too much for guys on a forum to unpack in a linear way so it's hard to get clarity. In my case, I have no plan to get anywhere near this trucks max capability so I can afford some degradation of performance in change for efficiency. If not an electric fan, are there thermostatically controlled clutch fans that perform better than OEM? Hope to hear from you. Thanks Dave
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