DodgeTrucks.Org

[rob92xj]

I have been told that in order to get better fuel mileage out of my 03 Ram 1500 Quad Cab. It is a stock 5.9L, 46 RE trans, 4x4 off road package, 3.92 gears, 28570R17 BF Goodrich All Terrains, just turned 36000 miles. It had a 2.5 inch dual exhaust installed before I bought it with a Flowmaster muffler I don't know which series it is. I should get a Superchips programmer, cold air intake, throttle body spacer and a set of headers. The truck gets 11.7mpg both in town or on the highway unloaded. I'm afraid of how bad the fuel mileage is going to be towing my Cherokee from NC to PA especially with todays fuel prices. gas prices

[amc racer]

What kind of improvement are you expecting for the investment?
Remember, it wasn't built as an economy vehicle.
_________________
69 AMC 12.79@105.9 4,200 lb barge with a 33 year old engine (Car Craft June/05)
99 Ram 2500 CC/LB CTD 4X4 , full Magnaflow stainless 4", Edge EZ, AFE
There's no such thing as too much truck.

NAMDRA Officer/Member#2923

[Steve00Ram360]

any mod that improves low end torque should help towing mpg... IMO...
_________________
2005 Ram 2500 QC 4x4 5.9 SB
edge w/attitude, 30" magnaflow muffler, AFE Stage 2 pro-guard filter

[Sexmonkey]

The best way to get better engine efficiency is to make it breath easier. So a cold air intake (being a Home Depot Special or one from K&N) A ported throttle body like an F&B, Ford Motor Sport injectors that atomizes fuel better that the stock injectors becuse of them having four pintels to the stock injectors one. I'd forget the about throttle body spacer as they are ment for wet intakes. Headers are a great way to free up power and get better mileage. And seeing that you already have duals, I don't know why the past owner didn't go the whole nine yards??? Porting you stock manifold or getting an M1 helps with breathing. Getting rid of that big clutched fan and getting a good electric like a Flex-a-Lite 180X. I've also found a great mileage improvement with an underdrive crank pulley.

[Chap]

4.56 gears are going to be the best mod for mileage and towing power. I have done most of the mods you listed and have seen very little mileage increase. I have 3.55 gears with 285 70 17's which really kill my power. Regearing is the way to go IMO.
_________________
Chap
Semper Fi
[size=10]02 1500 QC 5.9

[HankL]

Making the engine 'breathe easier' will not change the MPG.
Making the fuel injectors 'atomize' better will only improve MPG by 1-2%, as proven by the Compressed Natural Gas (CNG) versions of Dodge trucks.
4.56 gears will hurt MPG at steady highway speed in the 55-75 mph range.
------

This was written for second gen Rams
and has been modified but needs
to be re-written for 3rd gen Rams
but the basic principles apply.

With the dual sparkplugs and deep-in-block knock sensors the 5.7 might really
benefit from a special design piston that raises compression ratio and shifts
the combustion space over toward the exhaust side.

Aerodynamics is even more important on 3rd gen Rams to improve highway mpg
because they have gotten taller, wider (increases frontal area) and blunter
(worse in engineering term called Cd or 'coefficient of drag').

Those with Cummins engines may first want to read the 'White Paper'
from Cummins called:
"Secrets of Better Fuel Economy: The Physics of MPG"
which is oriented toward 18 wheel trucks but 90% applies to Ram pickups too.

http://www.cummins.com/na/pdf/en/products/truck/MPG_Secrets_Whitepape.pdf

beginning of original post:

Ram Pickup MPG improvement discussion :
{last modified 09-20-05}

Many Ram pickup owners start trying to improve MPG by first trying engine
modifications. Unfortunately, the efficiency of most modern engines is
already highly developed after 100 years of improvements, and this is the
toughest place to start, and many Ram owners make bad choices and waste money
that could have simply been spent on more gasoline.

The cheapest and most cost effective mods are usually aerodynamic improvements
that help high speed highway MPG, because a factory stock Ram has the Cd of a
brick, perhaps because many buyers value a big grille over a slick shape.

Second easiest MPG improvement comes when it is time to buy new rubber, where
good choices about the rolling resistance of tires will improve both City and
Highway MPG. Unfortunately finding information about what engineers call Crr
of a tire requires a good deal of looking and most tire makers actually hide
this information.

Next, there are drivetrain mods that will allow your engine to operate at 2/3
throttle and the best piston speed. This is where it turns fuel into
horsepower most efficiently even without internal engine part changes. Yes, I
said 'piston speed' and not a 'magic' rpm range called 'The Powerband'

Last, for the most work and the most money, there are mods to the engine
itself that will improve fuel efficiency when the throttle is only partially
open, but be prepared to give up some of the engine stuff you read in the past
in old hot rod magazines that was based on engines operating at full throttle
and meant for producing maximum horsepower.

This is a long article that is divided into three main sections: aero mods,
tire mods, and engine&drivetrain mods. At the end are weblinks to much
additional information. Feel free to skip to anything that suits your fancy.

AERODYNAMIC MODS

A hard tonneau can lower the aerodynamic drag. I installed a ARE
hard tonneau and found it was good for about 1 mpg improvement.

Ford Motor Co officially says that a soft tonneau is good for +1 mpg on the
F150 and
tried to get the EPA to allow them to add this to their highway MPG result by
re-classifying the tonneau 'standard equipment' back in 1999.

This Snugtop F2 hard tonneau has a built-in 'Roofline Extention Spoiler' on
the back
that might help MPG a bit more than a conventional design.


Fibernetics has a similar rear spoiler with a bit more angle, shown here on a
F150:


There is an interesting student project on a aero improvements tried on a
Dodge Ram model truck several posts down at this link:

http://www.dodgetrucks.org/forums/viewtopic.php?t=52115

If there are astericks in the above weblink, replace them with the letters
d-o-d-g-e-t-r-u-c-k-s.-o-r-g without any dashes, or go directly to the stored
old pages here:

http://web.archive.org/web/20030414190338/http://mars.acnet.wnec.edu/~ehaffner/did.htm
and
http://web.archive.org/web/20030414234348/mars.acnet.wnec.edu/~ehaffner/Tonneau.htm

Note that the students found that conventional camper tops
and removed tailgates hurt, but tonneaus helped about 11%. The Society of
Automotive Engineers (SAE) gave these students a prize for their experiment.

It is possible that a 2inch front/4 inch rear drop on a Ram suspension could
improve the aerodynamic drag. There is some evidence that on a 1996 Indy Ram
this improved the Cd by a few hundreds.

The 3rd gen body on the SRT10 Ram uses a 4/6 inch lowered stance, a rear wing,
tonneau, and perhaps partially block off of the 'too big' radiator grille to
lower its aerodynamic Cd from the 0.50 of the stock 2500 Ram to the SRT10's
value of 0.45

One reason the Chevy Siverado gets better highway MPG than a Ram is that it
has a lowered
drop for better aerodynamics compared to the Ram and F150. {The Silverado
also is not as high, slightly narrower, is about 400 lbs lighter, and has an
5.3V8 with a shorter stroke and 9.9 compression ratio.}

Bug shields at the front of Rams nearly always hurt MPG.

The Dodge Ram Diesel that set the Bonneville speed record had 'Mooneye' wheel
cover discs. These are supposed to reduce aero drag by 1-2% but hurt brake
cooling. I also notice this Ram had mirrors and wipers removed.


A MPG test over a roundtrip of a section of I40 at a steady 70 mph showed
0.7 MPG worse without the Ram's stock front bumper air dam, than with the
stock air dam in place. Other 2500/3500 Diesel Ram owners have reported
better MPG after taking off their air dam on the TDR website - but those tests
did not seem to be carefully done.

I have recently had some aerodynamic success with home-made little aluminum
tabs called 'Wheeler Vortex Generators'. I mounted 5 just behind the side cab
windows, and another 5 just in front of the rear brake lights. These improved
my coasting speed down a 6% grade hill by 2 mph, and also improved MPG at a
steady 70 mph by 1 mpg.

I had previously tried this commercial product on the roof of the truck, but
it did not
appear to work in my test runs:



The vortex generators I made were cut from 5 inch by 7 inch aluminum
'flashing' from Home Depot. You cut the flashing into 3 and 9/16th inch
circles, and then bend the sides up to form the 'wings'. A circle of course
has 360 degrees. The front of the wings take up 107 degrees of the circle,
and the back takes up 22 degrees. I used 3M 'Super Strong' outdoor mounting
tape from Target to stick the vortex generators to the truck's sheet metal.
The finished product looks like this:





I am still testing with the Wheeler Vortex generators. I have tried bending
dimes into tiny ones for the mirrors - but no measureable change. I have also
tried little 1.5 inch ones on the bottom of the Ram airdam - felt more stable
but MPG tests showed worse results. The best results have been on the sides of
the cab and on the sides of the pickup bed ahead of the tail lights. This
inexpensive mod can be good for better MPG especially at higher speeds.

It has occurred to me that with a heat gun to soften the plastic you could
make
these vortex generators out of the various sized computer CD's or DVD discs
but
I have not tried that yet.

There is also a commercial vortex generator called 'Airtabs' that is perhaps
a bit lower in drag than a home made Wheeler type. These are available in
black, white and clear plastic. They are $3 each.





TIRE MODS

Increasing the air pressure in your tires, and picking a narrow 'rib tread'
commercial delivery truck type tire that has low rolling resistance
definitely will help MPG.

Raising the air pressure by 15 psi to the max 70 psi in Goodyear Wrangler
HT 235/85R16E tires increased my mpg by +1 in a 311 mile
test run - but the ride was bone jarring. A narrow, highway rib tire like the
HT gives the lowest rolling resistance. Wide, aggressive tread tires can be
three times harder to roll. It might pay to have a 4 tire set for the weekday
commute, and a weekend mudder wide tire set.

Consumers Reports is the only organization I know of that tests for rolling
resistance of tires.
Quote from CR:
" Fuel mileage at a price. Some tires roll with less drag than others. The
lower a tire's rolling resistance, the more fuel you can save. Those savings
can be significant. {Pickup and SUV} Tires with the lowest rolling resistance
delivered nearly 2 mpg more at a steady 65 mph in our highway tests {2003
four-wheel-drive Ford Explorer XLT 4x4} than those with the highest rolling
resistance. The catch: While some high-scoring tires had low rolling
resistance, most tires with the lowest rolling resistance also had lower
overall scores."

In their 11/2004 Pickup & SUV tire test CR the
lowest rolling resistance tires rated 'excellent' were the:

Bridgestone Dueler H/T (D684)
Michelin Cross Terrain
Continental ContiTrac
BF Goodrich Radial Long Trail T/A

The Pickup & SUV tires with the worst rolling resistance were the:

Pirelli Scorpion STA
Kelly Safari Signature
Yokohama Geolander H/T-SG051

A tire with a 'very good' rolling resistance and high scores in other handling
and braking tests was the Hankook DynaPro AS RH03

The California Air Resources board is pressing the tire companies to make
rolling resistance measurements on tires freely available to the public by
2008, one of the few worth while things CARB has ever done in my opinion

The lower profile 17 and 20 inch tire designs used on the 2003-2005
5.7Hemi Rams have a 'sticker' tire tread and higher rolling resistance than
earlier year Rams. It is probable that if a manufacturer makes available a
235 85 R17 tire in Load
Range E it would be lower rolling resistance than the stock tires and might
improve MPG by 1-2 at 70 mph.

The 2006 Ram press release says the new model will have 'low rolling
resistance tires.'

ENGINE, LUBRICANT, EXHAUST & DRIVETRAIN MODS

Switching to synthetic lubricants - - engine oil, diff, Amsoil C+ Mopar-spec
transmission fluid, and syn greases in wheel bearings is good for 2-5% MPG
improvement. That is only about 0.5 mpg but every little bit helps.

Larry Shepard writes in the 'Magnum Engines' book published by Mopar Perf that
running engine oil and transmission ATF levels 1-0.5 quarts below the 'add'
marks on the dipsticks can increase MPG slightly due to less oil drag. If you
do this, you must check levels very frequently to see that you don't drop oil
levels even lower into the 'danger zone.'

Another 'non-sexy' but effective way to increase mpg is to keep an electric
block heater on while the truck is parked. The Dodge PCM computer richens the
mixture until the coolant temperature gets to 147 degrees F. By keeping the
block warm the engine goes into the more fuel efficient 'closed loop' control
sooner. This MPG improvement works best on trucks that do short trips. At 8
cents per kw-hr electric rates, running a 700 watt block heater for 8 hrs
costs 45 cents.

I changed out my original 3.55 differential gears on my 1995 Ram 5.9V8 46RH
auto to some $75 new-in-box (but 20 years old) Mopar ones of 3.21 ratio in
hopes of better mpg. I got about a
1 mpg improvement at 70 mph. Quarter mile times got worse by 0.75 second. My
5.9V8 now accelerates about like a 5.2, but has about a 5 mph increase in top
speed in 3rd gear as the gear ratio is more matched to peak hp. There is also
less engine noise while driving.

The Performance Trends software Fuel Economy Calculator predicts that above 74
mph a totally stock 1995 Ram 5.9V8 gets best MPG with a 3.55 diff gear, but
that if either the truck slows down below 70 mph, or the aerodynamics of the
truck are improved with such things as a tonneau bed cover or vortex
generators, then a 3.21 diff gear gives better MPG.

Note that on the 5.7Hemi with the new auto trans the overdrive gear ratio was
made "taller" to 0.67 from the old 0.69 at the same time that the 17 or 20
inch wheels & tires were made larger in diameter. This has an effect like
changing from 3.55
to 3.21 in the experiment above. The 2006 Hemi Rams with MDS come with a
factory standard 3.21 differential ratio.

A less restrictive muffler can help on a Ram. I switched from the stock
stainless steel muffler to Walker's 'QuietFlow' type made of aluminized steel
and gained about +1 mpg and dropped 0.2 seconds from the Q'mile. The QuietFlow
is as quiet as the stock muffler and has a 'Helmholz Resonator' section to get
rid of 'Drone' at highway speed rpms like the stock muffler had. Walker also
owns DynoMax, and the tech on the telephone told me the DynoMax is about 10%
less
restrictive than the QuietFlow but much louder. After 15,000 miles, my
QuietFlow began to rattle and I had to squeeze a dent in it with a large
C-clamp to stop the noise.

I later replaced the QuietFlow with a 30 inch long 'straight through' DynoMax
UltraFlo Stainless Steel 2.5 inch in, 2.5 inch out.

http://www.dynomax.com/mufflers.stm

part number 17298. This cut the wide open throttle exhaust backpressure from 7
psi to 5 psi. This reduction in backpressure only yielded a gain of about 0.2
MPG. The Ultraflo 17298 was a little louder than both the stock muffler and
the QuietFlow but just barely. Unfortunately it had a 'drone' at around 1800
rpm because it did not have the Helmholtz Resonator section like the previous
two mufflers. I later had to add an additional 16 inch long UltraFlo at the
very end of the pipe as a tip to eliminate the 1700-2000 rpm resonance when
cruising in overdrive. If you have a muffler without the Helmholtz Resonator
section you need to avoid having your tailpipe length from muffler outlet to
exhaust pipe tip anywhere near 66 inches - otherwise it will make this 'drone
noise' the same way a church organ makes a deep tone with a special length of
pipe. Make your tailpipe either much shorter or much longer.

I also moved my exhaust outlet to face rearward. A rear facing exhaust oulet
has a very very small 'jet engine' push to it - notice most cars exhaust
backwards - but trucks that pull trailers need a side exhaust to safety
exhaust carbon monoxide away from where it could cause
a deadly build up inside a camper.

On the 5.7 Hemi Rams, the large exhaust pipe sizes, muffler and resonator are
already fairly low restriction.

Headers are heavily advertised as helping MPG - a psychologically trick that
helps create sales - but in most cases headers don't do much because the
primary pipes on them are too short. Many headers are put on at the same time
as new less restrictive exhausts - and the header gets the credit for what the
bigger muffler actually did.

If you do buy a set of headers, try to get a custom set with primary pipe
lengths around 42-46 inches and don't worry if the primary diameter is
anywhere from 1.375 to 1.750 inches. This is in line with what Larry Shepard
found works best on the street with Mopar smallblock V8s, and it also agrees
with the estimates of the PerformanceTrends software program 'Engine Analyser
3.0' about getting torque gains from 1500-2000 rpm and then again from
3800-5000 rpm. The short primary pipe lengths that most header companies sell
give gains from 4000-5000 rpm only and don't really improve MPG in day to day
driving. To get the most MPG gains from a set of 42-48 inch primary pipe
headers you would also need to change your differential gears to a lower
numerical number - like 3.55 down to 3.21 - to make use of the extra torque
now available at the lower rpms.

A carefull MPG test of a 1995 1500 SB CC Ram with the 5.9V8 AT (3.21 diff)
with and without the "viscous clutch" radiator fan blades showed a 0.8 MPG
improvement without the fan. No overheating occured in this steady 70 MPH
test run over 212 miles.
There was also no sign of overheating at stoplights or city driving in
mild winter temperatures. Several Diesel Ram owners have posted that they can
run without a fan in winter and gain 0.5 to 1 MPG.

With the electric fan & clutch fan combo on the 5.7 Hemi Rams it is probable
that the clutch fan could be removed for all but the hottest weather or towing
service.

Weight reduction is supposed to improve City MPG where acceleration dominates.
The rule of thumb is
" A 10% reduction in weight yields a 6% improvement in City MPG."
So 540 lbs off a 5400 lb Ram might increase 14 MPG to 14.8 mpg.
At a steady 70 mph however, a 10% increase or decrease in weight only affects
MPG by about 3%.

The US Army is giving some of your tax dollars to Ford as a Research grant to
try out ways to cut the weight of a pickup truck by 25%.

Aluminum wheels save 40 lbs total. New Aluminum Magnum heads save 46 lbs.
Aluminum diff and rear axles saves 150 lbs. Fiberglass leaf springs save 75
lbs or monoleaf steel springs save 40 lbs. Do Google searches for 'monoleaf
spring' or 'fiberglass spring' to find suppliers who can make such springs for
Ram pickups.

Do you really need that rear bumper - are damaged bumpers less expensive to
replace than damaged sheet metal?

It is possible that 'Rhoads' style variable hydraulic lifters installed on a
Magnum engine would increase MPG by opening the exhaust valve later and nearer
bottom dead center and closing the intake valve sooner. One Ram owner with a
heavily modified 406 stroker Magnum V8 measured a 3 MPG gain when Rhoads
lifters were installed, but his camshaft was pretty 'wild' to the point that
he only had 7 inches vacuum at idle originally and that improved to 11 inches
of vacuum after the Rhoads lifters were fitted.

http://www.rhoadslifters.com/new_products.html

A 'RV' grind camshaft with lesser duration does this too.
This gets the last little bit of energy out of the combustion
pressure, increases 1500-2500 torque, but it also hurts higher rpm horsepower.

Higher compression ratio pistons are a reliable way to get better MPG.
Usually this means you have to purchase more expensive higher octane gasoline.
Raising the compression ratio from 9 to 9.5 is estimated to give 1% better
MPG. On a Magnum 5.9V8, changing the stock head gasket thickness of 0.047
inches to a Cometic 0.025 gasket will raise the compression ratio from 8.9 to
9.3. Replacing the stock 5.9V8 pistons (with their -13 cc depressions in the
crowns) with flat top pistons of compression height 1.626 inches will raise
the compression ratio from 8.9 to 10.2 Using flat top 1.67 inch compression
height pistons will raise the compression ratio from 8.9 to 11.3

This webpage has hard to find details about compression ratio increases from
milling cylinder heads of various sizes and makes.
http://home.isoa.net/~mharrisj/mill.html

Jim McFarland is an advocate of modifying piston tops. His design for the 4.00
inch Chevy 350 piston could easily be applied on flat top Magnum 5.2 pistons:



The 'soapdish' piston top on Magnum 5.9V8s might need some modification but
the 3 sets of dimples might still go in the same general areas. McFarland
claims 2-5% gains from this piston top modification. More info at:
http://circletrack.com/techarticles/99078/

Special ceramic coatings on the crowns of pistons and on the combustion
chamber of the cylinder head can improve both fuel economy and torque by
holding heat inside where it can produce pressure on the piston. Racing
engine builder Joe Sherman states that these coatings can add 2-3% to
performance, but if professionally applied they can be so expensive that the
mod would not pay for itself in fuel savings. There is an article about
applying coatings yourself at:

http://circletrack.com/techarticles/general/139_0307_coat/

Fitting 6.1 Hemi cylinder heads on a 5.7 Hemi should boost the compression
ratio by about 1 point, and the sodium filled exhaust valve on the 6.1 cyl
head would also help control pinging and detonation with this higher ratio.

There are combustion chamber designs that claim to allow compression ratios of
12 to 14 on 87 octane gasoline. You can read about them at:

http://www.theoldone.com/articles/The_Soft_Head_1999/

Sparkplug and ignition advance changes.

I did a careful test run of 311 miles after indexing sparkplugs in a 5.9V8 and
measured what might have been a 4% improvement. That could be random
variation. To index the plugs, buy 16 instead of the usual 8 and choose plugs
that tighten down so that the gap
points toward the V of the engine and the ground electrode is on the fender
side. Return the 8 plugs you don't use to the store or give them to another
Ram owner. This puts the metal post of the ground electrode over against the
metal wall of the cylinder head where it does not
block the growth of the flame. See this webpage for a view of the combustion
chamber. In the picture the bottom is toward the fender and the top is toward
the center V of the V8 engine:



There is an article with several good illustrations of sparkplug indexing at
this Phord site:

http://www.fordmuscle.com/archives/2000/07/indexplugs/index.shtml

On a 5.7Hemi, it is very probable that by re-arranging the stock 16 plugs to
their best position in the cylinder that is 'lucky for them', you could
achieve indexing without buying more than 4-6 additional plugs at most,
perhaps none at all. Aim the open gap toward the exhaust valve.

Tests of the Bosch+4 sparkplugs at 60 and 70 mph highway speeds with 87 octane
gasoline found no MPG improvement - actually a slight loss - on a 1500 1995 SB
CC
Ram with 5.9V8 AT. A further test of the Bosch+4 sparkplugs with one of the
electrodes closest to the exhaust valve cut off (making a Bosch+3) also showed
no MPG gain. Consumers Reports found similar results when trying Bosch+4
sparkplugs on a Honda.

There is controversy about MPG and thermostat temperatures. Pure theory says
that cooler air intake temperatures give improved MPG because cooler air takes
slightly less hp to compress, and if the thermostat is cooler on old fashioned
iron or aluminum intake manifolds with coolant cross-over passages there will
be less temperature rise in the intake air as it passes through. Modern
intake manifolds such as the ones on the 4.7V8 and 5.7Hemi are made of
insulating plastic so this does not apply as much - although the incoming air
can still pick up heat from the metal cylinder head ports.

But hotter oil on cylinder walls has less viscosity and creates less
friction against the piston rings - which can also mean better MPG. The
Cummins 'Secrets of Better Fuel Economy' white paper listed at the top has a
graph showing
this on page 12. Theory also predicts that hotter block walls and cylinder
heads will absorb less heat from combustion and permit a greater pressure
'push' on the
piston.

Some Dakota owners who switched to 180 degree thermostats have reported less
ping, peppier acceleration and about +1 mpg, although most reports like this
are just about what their next tank of gasoline yielded - not a careful test
that you can trust.
Other Dakota owners reported no mpg change or a loss. Four Wheeler magazine
reported +0.8 mpg gain with a 192 to 180 deg thermo swap in a 454 Suburban.

My own experiments with failed thermostat that cracked and stayed open at
around 140 degrees, then later thermostats of 180, 195 (stock) and 205 showed
no significant
improvement in MPG at steady 60 mph highway cruise on a 1995 5.9V8 Ram CCab
shortbed, although the 205 did show a small 0.2 MPG gain in one 300 mile test
run. The 180 degree thermostat also did not reducing pinging, nor did the 205
thermostat increase pinging. This may be because the PCM computer senses
coolant temperature and either advances or retards ignition timing as
necessary according to the tables in the memory of the computer. The cracked
thermostat that stayed open at about 140 did reduce pinging. When you read
that 180 degree thermostats reduced pinging on old carburetor engines that
might be true, but consider that todays computer controlled engines 'have a
mind of their own.'

The Fuel Economy Calculator from Performance Trends software predicts that a
change from a 195 degree thermostat to a 175 worsens MPG by about 0.20 at a
steady 70 mph.

Respected tech editior Marlan Davis of Hot Rod magazine has reported that
all things considered, fuel economy is better with coolant at 210 degrees F.
Perhaps that is why the factory thermostat on the 5.7 Hemi is now marked 203
F, which is were it begins opening. Note that on 4.7 and 5.7Hemi engines the
thermostat position and function has been totally redesigned to control the
coolant in, rather than the coolant out temperature. The 5.7V8 now also has a
closing bypass post sticking out from it that closes off the passage and
results in greater coolant flow to the radiator once the engine is up to
designed temperature.

Undersized crank pulleys can increase MPG slightly by driving the power
steering, air conditioning compressor, and water pump at lower rpm where there
will be less friction.
Some who have tried undersized pulley sets report an additional oversized
alternator pulley in a pulley set is too slow for the street truck that may
have to idle a long time without enough
rpm to charge the battery. The horsepower that an alternator consumes is
mostly set not by the rpm it turns, but by how much the 'voltage regulator'
inside the Ram pickups PCM computer increases the 'field' inside the
alternator. Because of this I see no benefit in slowing an alternator down -
no significant horsepower will be saved.

The last MPG technique is the simplest, but the one few of us want to hear. I
have done several 300-400 mile test runs at steady 60 or 70 mph on I95.
Slowing down from 70 to 60 mph saved 3-4 mpg each time. I also did a 80 mph
test run once driving with the crazy flow of traffic from north of West Palm
Beach to Ft Lauderdale. This lowered MPG by 4 compared to going 70 mph.

Notice that I don't claim this slowing down is 'cheap' because of the
question: 'How much is your time worth ?'

If you want to read more about MPG improvements that work,
the US government has put a book online at:

http://books.nap.edu/books/0309045304/html/198.html#pagetop

In the Appendix of this book is an interesting table where the Dept of Energy
sent a questionaire to all the auto makers and asked them what various mods
were worth to improving MPG.

The EPA has put out a long report on fuel economy trends from 1975-2005.
There is much good tech info here, especially around page 36.
http://www.theautochannel.com/link.html?http://www.epa.gov/otaq/fetrends.htm

Kevin Gertgen's Fuel Economy Calculator software is very impressive and can be
read about at:

http://www.performancetrends.com/fuel_economy_calculator.htm

There is an online Java based webpage calculator at:

http://www.bgsoflex.com/mpg.html

Jeffery Diamond's Mopar specific gas mileage mod table is worth pondering:
http://victorylibrary.com/mopar/mileage-c.htm

There is a collection of aerodynamic links concentrated on pickup trucks at:
http://www.dodgetrucks.org/forums/viewtopic.php?t=52115

[amc racer]

Somewhere along the line, you have to calculate the return on your investment. If yiou're going to sink in 500 or 1,000 or more and net a real 1 mpg increase then how long will it take to recover the invested money.
_________________
69 AMC 12.79@105.9 4,200 lb barge with a 33 year old engine (Car Craft June/05)
99 Ram 2500 CC/LB CTD 4X4 , full Magnaflow stainless 4", Edge EZ, AFE
There's no such thing as too much truck.

NAMDRA Officer/Member#2923

[dullie]

i have found the only way possible to get better mileage in my 96 1 ton v-10 is to slow down.when im on the freeway instead of doing 65 to 70 ,i do 60 no matter what .i add about 1.5 miles the gal. .the only money it cost was a few more minates on a trip.

[purdueranger]

One thing you have to look at too is do you really need this big of a truck if you are worried about gas milage. If gas is costing you more money than you can afford then it is time to get something smaller. It's a price to pay when you drive a big truck. Mods that I have done to get better gas milage also helped performance. If the engine has to work less at a lower rpm it will help you out. If you don't have to lay on the throttle to get moving then you will be saving gas. did a trick of not hitting 2000rpms when driving the summer and I was averaging almost 17mpg. If i took the motor past 2k just driving around my milage was about 15mpg. I had about a 50:50 ratio of highway and city driving to work.

On that experiment was only taking the motor up to 2500rpm when getting on the highway but slow takeoffs from stop lights and sitting in traffic.

[salzan]

When I started trying to improve my mileage about three months ago, I was getting 12.5 average. Since then I've added a 3" cat-back system (went to 13.6), removed the stock fan and went to dual 12" electrics, added 5lbs. pressure to the tires and put a mental ceiling of 70 mph on my driving habits.
My current average is 15.1 mpg. Next will be aero tricks.

HankL, in a former post you mentioned doing a test with the air dam removed, I've done searches and can't find the test. Do you have a link?
_________________
94 1500 4X4 SLT
5.2, Auto
Denso iridium plugs
180 Thermostat
K&N Filter
K&N 3" stainless cat back
265/75/16 Bridgestone AT Revos
Rancho RSX shocks
Raven cap & liner
Mobil1 in engine and trans since 98

[HankL]

At the moment I have extended my stock airdam down another 2 inches with a piece of 'garden edging.' The truck handles well at higher speeds but I cannot detect any MPG change for the better.

Here is the old post:
----
I got frustrated today after getting word that a governmental decision I was
waiting for would not be forthcoming - despite being promised an answer for
the last two weeks.

In order to blow off steam,
and not end up with a completely wasted day,
I decided to try to find an answer to that urgent question weighing on the
minds of all mankind:

Does that Air Dam under the front bumper of a Ram do any good ?

I gathered up some music I hadn't listened to yet, and drove over to the
Clayton NC exit of I-40 just to the east of Raleigh and filled up with Exxom
87 octane. ($1.55 per gallon here)

I then drove in a loop trip down I-40 to Wilmington NC and back. The distance
was 218.7 miles. I started around 10 am when the temperature was about 73F.
There was a light wind from the south, which opposed my East by Southeast
route - at least on the first leg.

I drove a steady 70 mph with the cruise control set, and had the air
conditioner on with the temp control at the 11 o'clock position. Traffic was
light and I only had to take the cruise off 3-4 times on the trips.

I did drive by a forest fire just off the interstate though - complete with a
helicopter overhead with a underslung bucket that sprinkled water drops on my
windshield as I whizzed by without delay.

On the first trip with the air dam still on,
I used 11.53 gallons according to the gas pump,
which for 218.4 miles by the Ram's corrected odometer gave me a MPG of 18.94
miles per gallon.

I also reset the Oztrip computer and checked with it too during the trip. At
the end it said I used 11.60 gallons over 218.7 miles for an Oztrip estimated
MPG with the air dam on of 18.85

I then removed the air dam in the gas station parking lot.

If you do this be sure to spray WD-40 on the upper threads of the T-25 Torx
heead screws first. I first tried to remove them without the WD-40 and
stripped the first one - which then took 15 minutes to remove using a
vice-grip on the exposed threads inside the bumper. I thought Torx were
supposed to be strip-resistant ? With the WD-40 soak, all the rest came out
easy in less than 5 minutes. There are also two plastic rivets on the outside
edges (why Dodge, why not just two more torx's ?)

The second trip started around 2pm.
The temperature had gone up to about 80 degrees. Without the air dam the
Oztrip immediately showed less mpg at the steady 70 mph. I also felt I could
hear more wind noise - it seemed to come from the driver's side wheelwell
direction. Later I also thought the coolant temperature gauge was about 5
degrees higher at about 185 - but that might be due to the higher air
temperature outside.

Without the air dam, the Exxon gas station pump said I used 11.969 gallons
over 218.4 miles for an MPG of 18.25

The Oztrip computer estimated I used 11.99 gallons over 218.7 miles for an
estimated MPG of 18.24

So it looks like removing the air dam cost me 0.7 MPG at a steady highway
speed of 70 mph.

I guess two valid questions about a test like this would be:
1. "How much would two identical back-to-back trip MPG's differ by just
natural variation? "
2. Could anything else have caused the MPG difference ?

I do not know the exact answer to the first one - but based on the other test
runs I have done in the past I would guess natural variation would be
something like 0.2 to 0.5 mpg.

On the second question,
I imagine that varying wind speed might be a hidden cause. The cross wind from
the south did hurt the southeast bound leg of the trip, and help the northwest
bound leg - I could see this on the Oztrip meter. I would guess this wind was
about 10 mph.

It is also possible that the slight increase in air temperature made the air
conditioner work harder ( I personally doubt this) or perhaps the 7 degree F
hotter intake air made the engine slightly less efficient (the engine
textbooks mention this, but it is a very small effect).

I had hoped this test would have turned out the other way.
One reason I decided to do it was that a poster on the turbodieselregister.com
website had said that he had gained 1 mpg after taking his air dam off, then
lost 1 mpg when he put it back on later.
http://www.turbodieselregister.com/ubb//Forum17/HTML/000903.html
http://www.turbodieselregister.com/ubb//Forum17/HTML/001147.html

I was hoping to find another trick to gain some mpg, under the theory that
maybe the air dam was there only to reduce front end lift at high speed.

There is a book called 'Race Car Aerodynamics' that has a graph from a Society
of Automotive Engineers SAE paper that shows that air dams up to about 4
inches high slightly help in reducing aero drag.

Since the Ram's air dam is just about 4 inches too - I guess it does aid in
reducing aero drag after all.

[salzan]

Thanks HankL. It's funny about the garden edging because that's exactly what I thought of trying. With the little lip along it, it seems a natural. Not to mention that it's readily available and cheap.
_________________
94 1500 4X4 SLT
5.2, Auto
Denso iridium plugs
180 Thermostat
K&N Filter
K&N 3" stainless cat back
265/75/16 Bridgestone AT Revos
Rancho RSX shocks
Raven cap & liner
Mobil1 in engine and trans since 98

[rob92xj]

I know the truck was not built for fuel mileage. I have a soft Mopar tonneau cover. The mileage is the same with the bed covered or uncovered. It is EPA rated at 12 mpg city and 16 mpg highway. I know the test procedures used and I know they are not always "real world". But the Chrysler/Jeep dealership I work for I have a customer who purchased the same truck from us 2003 1500 QC 5.9 46RE 3.92's everything is the same except the wheels he has the 20's and he adverages 16 mpg but he has installed a Superchips program, cold air intake and dual exhaust. I just wanted to know if anyone else has done the same with similar results. I bought the truck to tow my Jeep, but I setted for the 1500 due to the prices of a good used 2500 Diesel. Most 2000 were going for more than I got my 03 for with a hell of alot more miles on them. Next truck will be a Mega Cab with a Cummins in it though. By the way I had to relearn how to drive since buying this truck and I drive it like an old lady who cannot see over the dash that school buses flash me to move out of their way.

[Isaiah]

tonno cover and a cutout after the cat...after doing both at the same time, my mpgs went from 11.5-13.3 out of all the mods these helped the most with the gas probs. yes, the cutout when opened actually helps my mpg...might be because its so damn loud when i gas it too much that i avoid steeping on the gas hence wasting it..
_________________
THE NEW:
2007 Dodge Ram RC 1500
4x4 sport 5.7L Hemi
Electric Blue

THE OLD:
15.665@84.93mph
2000 Laramie Sport 4x2 5.9L
Performance Mods: SS Shorty Headers, Autolite 3923s, Flowmaster 40 duals, K&N fipk, 180* Tstat, Leaf spring clamps, Relocated IAT, Mopar PCM, MSD 6A, Blaster SS Coil, MSD 8.5 Wires, Optima Red Top, 2.5"cutout w/MPP2, No "meow", Fastman TB, 1.7 HS Roller rockers, M1

Style Mods: Debadged, Clear corners, Sony M800, 400w Rockford Fosgate 10", JBL 200W amp, 2/4 drop, Carriage Works Billet Grill, <5% tint in the rear, Red & Black wet okoles, AirLift, Underbody LED, moto metal 18x9s

[ofelas]

rob92xj - here's what seems to work on my 5.9 as far as mileage goes -

1. 21lb Design-3 injectors (Bosch 4 hole).
2. Electric fan (no clutch fan), running factory 192 degree thermostat.
3. Ported '92 exhaust manifolds (92 manifolds are 1/8th inch larger ID than all other 318/360 Magnum manifolds).
4. Single 3" exhaust with factory cat, Flowmaster 3" ID/OD muffler.
5. Amsoil synthetics in both diffs, engine, tranny, transfer case.
6. Tire pressures 33psi front & rear.
7. I run the factory 4.10s with 35" tires.
8. TransGo shift kit.
9. Mopar Performance R/T cam + 1.7 roller rockers.
10. K&N drop in filter inside factory fenderwell airbox.

I got a consistent 14mpg city & 17-18mpg highway at 70mph with 92 octane fuel (Mopar Performance computer).

All my mods were geared towards torque AND reliability, nothing fancy.

52mm TB, headers & a K&N FIPK-2 gave me LESS usable torque/gas mileage than the 50mm TB, '92 exhaust manifolds & factory intake.

Hope that helps.
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