My 04 Hemi quad cab 4x4 is averaging 9-10 miles around town at best and not a heck of alot more on the highway. I have modified it as follows. K&N cold air intake system ,Gibson dual extreme exhaust system. Tonneau cover. I did add a set of BFG All Terrain TA/Ko tires. The tires are 265 size up from 245
70/17 I think about an inch taller and inch wider. I don't go peeling out at lights or really pushing it. Is this common or should I be checking something? Truck has about 35k on the speedo. It's a beautiful truck but gas mileage sucks big time.
If your tires are an inch taller than stock, you are travelling farther than what the odometer says (and faster than what the speedometer says). Your mileage probably isn't quite as bad as you think.
On my Ram 5.2 Magnum 4X4 it has the first two that you did and then added the Mopar performance computer (you may already have this on the Hemi??), spacer on the intake and an MSD ignition system. Milage went from 12 to 17.5 if you are easy on the accelerator. I also have slightly larger tires as you do and my speeds are raised by about 5mph at 70. At 70mph I am actually doing 75mph so actual milage might be slightly higher. I doubt you will see as large an increase with the Hemi as I did with the 318, but it may help some. I did add a shift kit to the OD tranny at about 170,000 miles when it needed a rebuild (damn those Dodge trannies just don't last....:-) and it now has close to 175,000 miles on it and it still runs like new with oil pressure at 40-50lbs and no oil usage between changes every 3,000mi or so. The modifications were done at around 50,000mi or thereabout.
You put on a wider, taller, heavier, tire with a more aggressive tread, that would cost a couple of mpg with the added rolling resistance and rotational weight. You also raised the truck higher, that put more air passing under it. The K&N was waste unless you did a bunch of engine mod's. Your probably jumping on the gas to hear the exhaust and the woosh from the K&N.
You have a couple of options imo. Realize it is a 4x4 truck with a hemi in it that sounds nice but gets shitty mileage and enjoy it. Or dump it and by econo car. It is what it is.
But Roy, you gave him a black vs. white answer - the truck or any econo car. There are a multitude of options, including a truck and an econo car (and/or a bike, bus service, a skate board, not going anywhere, ask friends for rides, hitchhiking, etc.). Perhaps Buddism isn't that enlightening. ,:
This is hurting not helping MPG, especailly in town but many never figure this out. It has to do with letting exhaust blow off too quickly from cylinders because the engine sets its power for expanding gases, not explosions. Dual exhaust hurt more than help MPG in urban driving and it is a toss up if they help at all on highway because modern engine are well tuned from intake to exhaust and when you start hacking, MPG can take a dump.
This did not hurt
This hurt because the tires have a bit more rolling resistance and drag
Hemis can be real gas hogs. Engine with torque peaks above 4000 RPM are seldom their most efficent at lower RPM's and this engine is one of them. You have a few more things hurting you. First and foremost, your truck is ALWAYS dragging the front differentail and drive shaft. Even when not in 4x4 it is locked to wheels and consuming power. Figure on at least 1 MPG or more lost because of this drag. (even more in cold weather) Dodge is the only Detoit truck maker that does not have a front axle disconnect ( the left it out to save them a few bucks while potentailly costing you over 1000 bucks or more in extra fuel over life of truck) so they will always do worse than competion on MPG in 4x4 models. One thing you can do is use better fuel as 87 octane is a joke in that engine and it compromising power and MPG. Also run tires at near max pressure and change lubes in Tcase and axles if you have not already done so but do not expect miracles.
Howard, Your truck should be getting between 15 and 17.5 MPG depending on your driving habits. What was your mileage before the mods? That would be a good indicator. Secondly, the K & N will flow more air initially, but the filtration ability is no way as good as the OEM arrangement. Furthermore, over time, as dirt is gathered, the K & N will flow LESS air than a partially clogged factory filter. It would be wise to hook up a manometer between the air filter and throttle body and watch for vacuum during use, then you will know for sure. Additionally, if the exhaust has much less backpressure much of the ingested fuel could be exiting the engine because of reflected vacuum. This you would see as unburned hydrocarbons in the exhaust. Using a 4 gas analyser will show that as well. Steve
Maybe in your dreams or a 2wd one in a lighter truck with stock tires. I am not knocking Dodge but if you want a chance at a gas 4x4 with decent MPG for its size you have to get a Ford or GM because they unlike dodge do disconnect the front axle and differentail in 2wd. over 35 years ago when I first start buying 4x4 for myself they had lockout hubs and you could tell when hubs were left engaged and see it in MPG too. Yes so wise arse will say it was a 40 year old truck but that does not matter because new truck drags axle same way since there is no disconnect. Given todays energy concerns is is a bit of a farce that not a single Dodge 4x4 made has a axle disconnect all to save them, (not you) a little money building them.
I rarely say this, but you are incorrect, The 1500 Dodge Ram does disconnect the wheels at the front Diff., as well as the TC. It does so with engine vacuum in 2 WD. Please, for the sake of the other readers, get your facts correct before you reply. On my '96 5.9 (Gas) 5speed I regularly saw 17.5 MPG by keeping speeds below 50 MPH Steve
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