Been a while since I posted to the boards here- since my last post I sold my 97 conventional cab diesel (auto)for a 06 quad cab (auto)short bed. The 97 which I bought brand new got a best ever 19+ MPG, which over the years erroded to the 15s. When I picked up the 06 it was an extra clean used truck (2 months ago) with 67K. Like the orignal poster on this thread I was distressed to find I'm only getting at best 16 MPG. That BEST was on the highway at a steady easy speed.

I was going to post this question anyway- but saw this thread and decided to jump in. My one unknown with this 06 is any mods that might have been performed before I got it? I will state that this 06 is very-very fast! I do enjoy the quickness of the truck- but I'm questioning the MPG?

For the record- I'm not using the MPG of me "jumping on it" aganst it overall. Again- my best MPG was driving very easy. Could a "programed" truck cost mileage? Everyone says high performance mods should aid MPG- not distract?

 

haha well....it's a double edged sword.

Post your truck details. Can't make anything of the mileage until those are known.

 

It is not just RPM<, the h.p. it takes to go 75 mph is much higher than what it takes to drive 60. With poor aerodynamics the h.p. requirements go up like the national debt, real fast. Drop 10 mph and watch the fill ups extend, or don't.

 

What I bolded is pretty close to reality for what my 05 would get. I ran a Smarty S-06 with a pretty modest tune, and routinely would get 19 MPG at 70 and around 23 if i did the 45-50 MPH backroad route to and from work. That, on summer fuel, of course. On my maiden voyage, pre-Smarty, I averaged 17-18 MPG in the 70-75 MPH range, and saw as low as 13 (I-10, W TX, 85 MPH) and as high as 20 MPG on CA-1 from SLO to Monterey, avg 45 MPH) on winter fuel, truck having ~ 40K miles at time of purchase. Tires were upgraded to 34 inch from stock 32s.

Compare this to a bone stock 99 Ram 1500 QCSB 4x4 (essentially identical setup) that only got 15 MPG all day long. Best I ever got was 17 MPG taking a slower route for 150 miles.

 

99 Ram was still equiped with the ancient magnum engine which was very inefficient compared to the newer trucks equipped with the 5.7. I have seen several customers with newer 5.7 gassers (mds equipped) getting as good as mpg as the 6.7 diesels. If I were shopping for a truck today it would most likely be 5.7 equipped. My towing needs have all but dwindled to very occasionally..... at least my 01 ctd has long since been paid for and is in very good condition.

 

I can tell you one thing for sure, run some 35s and your mileage will go up. I know that seems ars backwards, but mileage is all about your rpms. If you're running 2200-2300 rpms, you can't get good mileage. Believe me I know, I'm having the same trouble on my 06. If I don't keep it in the sweet spot of about 17-1800, the fuel mileage is shot. But on my 07, I have 35s on it, and can run 80 all day and get 18-19 mpg which is plenty good for me, and that isn't driving like a grandma. I can't wait till tax return in january cause 35s for my dually is what the whole check is gonna go toward.

 

5.7's might get better mileage with tuner and other components but once you do that stuff the old 87 octane no longer cuts the mustard not enough octane. You have to run mid-grade aleast, if not prem. So the reason I bought a diesel, Is if I choose to throw a tuner at my 5.9 diesel my fuel wont have to change to support the new power it will give it may use more diesel fuel BUT I wont need more octane or a higher priced fuel. There is no way IMO that a gasser can run better then a diesel. It comes back to what you pay per gallon of which fuel that vehicle now needs. My last truck was a 2004 5.7 without the multi-displacement and auto. My mileage was not even close to what I get with my 2006 5.9 diesel 6-speed. I know I lost some mileage with the auto, but not as much as I made up with the 6-speed standard. As far as the size of the vehicle both were 4 door 4x4 shortbeds so size was about the same. Like I said before to get more power and try and use less fuel you needed to start filling up with gasoline that was more exspensive then diesel at least where I am at. This is how I looked at it and sold myself on the idea of diesel. If you think that you can make a gasser work better on gasoline cheaper then the price of diesel per gallon then your right you should have never gotten rid of the gasser. But in most places around the US your always come out ahead with diesel prices then paying MORE for mid to pre. gasoline. The amount doesnt really matter if the fuel is less exspensive. But if it is using less more exspensive fuel then it needs to be using alot less to offset the cost per gallon. I just knew I would come out better in the long run paying for diesel then for higher octane fuel that my 5.7 modified gasser would need.
Just my two cents..

 

Wind resistance is a HUGE FACTOR!

Hold a dinner plate out the window at 30 mph and then at 60 mph. You won't believe how much force moving through the air takes.

I smacked up the front of my truck in an ice storm and the front bumper is up where the bottom of the radiator sits now. I have no air dam underneath. My truck is getting 2 mpg less now than it was 2 weeks ago running the same 500 mile trip.

It goes in the shop today finally.

 

The Turbcharger will not spool without a load on the engine.

 

I agree with everyone else.. You want turbo "whine"?? Pull out the silencer ring (simple job - just did mine recently).. You'll hear it then.. Fuel mileage? Get rid of air filter box and install oversize air filter. Loose your muffler and straight pipe it.. that should help.. Also, if you have a computer overhead in the cab, set to fuel mileage and watch it as you drive.. You'll learn QUICK what to do and not to do.. Also, avoid excessive "warm up" time.. That will kill you mpgs..