Poor Mileage

Page 1 of 2  
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.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Howard Page wrote:

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.
--
Ken



Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
The good folks at the local Dodge Dealership Foss Motors in Exeter,NH reset the computer for the new tires. At a cost of $40-50.00 I'm getting my info from the overhead computer. The truck runs good and has plenty of power. Does anyone know if the computer they use to reset the trucks computer is the same one that other garages have or is it a propriety system that only Dodge has for Dodge vehicles. He plugged it in under the dash. I'll also check for info at www.dodgetruckworld. I'm a member of the NH chapter. Thanks hpage3

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
The overhead display MPG is known to be inaccurate, use real world miles traveled vs. gallons burned.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
In response to Ed H. 's post. I thought everyone should know:

Yes they are, but this one sounds close enough to me. my 8.0L got about 8 to 10 mpg 11 if i was real nice.....but yall know me, im not that nice =)
several friends with the 5.2 and 5.9 are claiming the same neighborhood up to 13mpg so 10 out of a HEMI wouldnt surprise me much.
oh yea best my wifes durango ever did was 15 on a long trip at 60 to 65 mph on the interstate. 13 with her long trips to work was the average.
sorry just my eperiance.
--
Chris

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

It's a big heavy truck with a big'ish engine. Mileage is going to suck. But I agree with you, it shouldn't be that bad. You've made a couple of engine mods, have you checked your actual air:fuel ratio? Ask around in your club, someone must have an LM-1 or something similar. Have you used a tuner like Haltech or Jet? The highest setting will give you a tad more performance than the mid setting, but your mileage will defiantly be worse. Have you checked for proper air pressure? If you're lucky, you can find someone with a tire pyrometer to set the pressure more accurately. If you can't find one, just add 5 psi to your current pressure and see what happens to your mileage.
--
.boB
2006 FXDI hot rod
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

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.
Ed
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

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.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Roy, how DARE you suggest that someone trade it in for something this simple! Careful the net nanny is reading and may chastize you!
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Ah, with Buddism, I gave the op a option. Further while practicing Buddism, I am never wrong!!!! <GBMFG> roy
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

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. ,:<) However, I must admit you weren't wrong - something to be said about Buddism, at least from the Buddist view. <BG>
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Larry is use to saying the above.<BFG>
- something to be said about

Yup, the sure is!! <G>
Roy
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Huh?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

C'mon pay attention!! "However, I must admit you weren't wrong"
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

You've never been to NH were mass transit means you have to go to mass to find anything reliable that goes anywhere you want to go ?; )
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Jeff, I live in MA. I know NH real well.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Fri, 17 Aug 2007 00:04:30 -0400, "Howard Page"

K7N is a waste of money

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. ----------------- TheSnoMan.com
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Yes, you the idiot and troll is back I see! Typical troll, just wants to stir pot and not really help anyone. ----------------- TheSnoMan.com
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

You are soooo sad.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Roy wrote:

You are soooo old.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Related Threads

    Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.