Mpg/oil/k&n

sober01s · #1 08-21-2009, 11:31 PM

I have a 2005 dodge dakota quad cab 4x4 with the 3.7 v6. Yrittium NGK plugs, K&N filter. Any hints on gas mileage improvemnt? I only average 16.5 on highway/city. Also does anyone find inprovement using synthetic compared to conventional oil. I use mobil 1 clean 5000 conv. Does anyone have the K&N air intake system, and do you notice any improvements.

This ad is not displayed to registered and logged-in members.
Register your free account today and become a member on Dodge Forums!

ericemery · #2 08-22-2009, 02:38 PM

A lot of guys claim low numbers with the 3.7... I am not sure if its because it has to work a little harder, or the gearing is fighting the motor, but its kind of strange.

I would suggest looking at an electric fan to help free up a little of that wasted power the clutch fan robs. I would also look into tire pressure and how aggressive the tread is. (also how soft the compound is...)

tires can make or break MPG. keep them inflated as high as you can (according to the sidewall info) with just a few tweaks to your driving habits, you could probably gain a little there too...

I have always ran full syn, so I am not sure how much we actually gain by switching...

popsnbeer · #3 08-24-2009, 10:37 AM

i would have to disagree somewhat with you Eric on the inflation of the tires. Although a more inflated tire has less contact patch w/ the road it will increase your gas mileage, you will be wearing your tread unevenly and also taking the risk of a blowout. Here in Phoenix, we need to be careful that we don't over or under inflate our tires so that they have room to expand when hot from driving. I would recommend sticking with the recommended pressure given on the side of the front door. Just my two cents :-)

cramerica · #4 08-24-2009, 12:09 PM

Highly agreed. Don't inflate the tires to max sidewall, inflate them to manufacturer's specs. Maybe spec +5 PSI if you want a little bump. I keep mine around 38 PSI.

16.5 MPG combined is totally normal. Consider:

1) You drive a 4x4 quad cab. The heaviest Dakota possible. I drive a crew cab 4x2, the lightest possible, and average the EPA ratings...16 city, 22-23 highway.

2) 3.7 and 4.7 get identical mileage under most conditions. Accelerating the truck to speed, and then continuing to push through the air, requires a certain amount of power. Whether you make it with 6 cylinders or 8, you are still burning the same abount of gas. I

3) Your driving habits have the #1 effect on mileage.

-Accelerate slowly,
-Read the road ahead to maximize coasting and minmize braking.
-**DON'T** use cruise control on the highway. Let speed fall off up hills, and pick it
back up on the way down. Drive like a big rig.
-Keep highway speed under 60 MPH.

I did all this for a couple tanks. It's boring, and you have to keep things safe, particularly when merging onto the highway. I also drive a stick. But I averaged 25 MPG before I got sick of it. Now, I drive normally, enjoy it, let the engine wind up a little bit where it feels more comfortable, and keep my eye open for a 4 cylinder Honda once the truck is paid for...

andix · #5 08-28-2009, 02:00 PM

I am considering also buying a tonneau cover (box cover). there are mixed feelings about those covers, but the little physics I know say that it will reduce drag created by the box.

all the manufacturers claim that the cover cuts up to 3 mpg. of course it's marketing BS, but everyone I've been talking to say there is some mileage improvement. I only found one person saying the opposite. but he's a carpenter, I don't see how he would be skilled in aerodynamics.

also, use some hypermiling tricks. try to avoid sudden accelleration and sudden brakes. let the car coast when possible. do not drive highways with your windows open. if it's too hot, put the fan on the first setting and let it blow through the dash vents or the floor vents. if you use the windshield vent, the A/C is gonna kick in even if the A/C button is off. (this is intended to dry and filter the air, as the air entering through that vent is supposed to defog/defrost the windows.) and very important, do not overload without reason. (here in Northern Canada I see people carrying their snowmobiles late in the summer, just because they're too lazy to take them off.)

baracis · #6 08-28-2009, 02:36 PM

My stepmom has a 3rd gen with the 3.7L, I have the 4.7L. I drive like an idiot and still get better gas mileage than her. I'm with Emery on this one.

popsnbeer · #7 08-28-2009, 05:08 PM

I have read different opinions on the tonneau covers. I read a few reviews comparing different trucks and some benefited and others did not. I'm pretty sure it has to do with the stock aerodynamics of the truck. Some of the truck beds actually create a swirl effect within the bed which actually acts as a buffer for the wind tunnel in a truck and by putting on a tonneau cover you essentially eliminate that effect. just my two cents, no articles to back that up.

LB · #8 08-28-2009, 10:45 PM

I installed a truxedo on mine, my commute is 75 miles per day and I check my mileage every tank. I have not seen any improvmet at all, I was hoping for maybe 1mpg but nothing.

Just my 2c
LB

sober01s · #9 08-29-2009, 05:04 PM

I have a truxedo on my truck as well and I have seen no improvement as well. and I have a 2005 3.7 v6 4x4.

andix · #10 09-01-2009, 06:21 PM

@popsnbeer & sober (no pun intended

) -
your truxedos are the soft version? if yes, do they have any struts to support them midway or at the thirds? if pressure is created behind the cabin and the cover is soft, it will be pressed downwards. if that's the case, the concavity that forms in the box will most certainly be the opposite of any aerodynamic improvement.
I'm asking this because I'm thinking of buying a cover myself.
thanks!
andy

EDIT: does anyone know of a manufacturer that makes sloped tonneau covers? like the ones cars in Paris-Dakar rally have? something that would start at the upper edge of the cabin and go straight to the edge of the tailgate? kind of like this one but without that ugly spoiler...