Fuel Econmy Upgrades

[AH64ID]

This showed up (unsolicited) in my inbox this morning from one of the Oregon Dodge Dealers:



Are you noticing that gas prices keep going UP, but your fuel economy keeps going DOWN? Then it is time to give

you fuel econmomy and performance a KICK!!! With our Special MPG Package.







We will perform a MotorVac fuel system Service, This service includes: replacement of your dirty air filter and replacing

the air in your tires with NITROGENall for just $199. 95 (regular priced upto $259. 95)



WOW... $200 to replace your air filter and put air in your tires. Or, you could buy magic beans, plant them and hope a biodiesel plant grows. I hope they don't snare anyone with this nonsense.

Thats silly... . Costco only uses nitrogen in there tires now... The benefits are that it doesn't have the tendency to slow leak like air and isn't affected by the temperatures that car tires see, so 65 psi is 65 psi in the winter and summer... . And it doesn't cost any extra. .

 

[rbattelle]

isn't affected by the temperatures that car tires see, so 65 psi is 65 psi in the winter and summer... . And it doesn't cost any extra. .

With all due respect, I disagree. In my opinion, nitrogen acts like an ideal gas just like air does. It will change temperature almost as much as air does with a change in temperature.

Gas constant for air is 286 J/kg*K
Gas constant for pure N2 is 296. 8 J/kg*K

If you work out the ideal gas equation (P=rho*R*T) for tires filled with air and N2 at the same initial pressure and same change in temperature, you'll get the following equation:

delta-P_air / delta-P_N2 = 0. 99

So that means that N2 will change its pressure 99% as much as air does with a change in temperature. So if your air pressure changes 5 psi between cold morning and hot afternoon, that same tire filled with nitrogen would change 5. 05 psi. Since most of us aren't using a tire gauge that can resolve 0. 05 psi, that means you would see NO difference in the pressure change between the two gases.

Those who believe nitrogen inflation will reap the benefits claimed by its proponents would do well to recall that air is over 70% nitrogen anyway.

Ryan

 

[AH64ID]

From what I understand the reduction in pressure flucuation is from the lack of moisture in pure nitrogen vs air... . So yes there may be a little flucuation, but not nearly as much... My wifes 4runner has costco tires and nitrogen that were put on last winter and the pressure is still where it was, +- 1, and its now 40-50* warmer out.

 

[DirtyDodge]

Ditto for me with my '98 Accord,5-speed A/C off.

My wifes accord doesn't even see those kind of numbers, though it is a auto v-6.



My truck will get just over 20mpg on the highway using CC and keeping the speed down. I average 17. 5 for mixed driving.



I read an article in the TDR magazine a couple issues ago that showed a 2wd 1 ton dually that got 30mpg on a trip, but they did quite a bit to it and they said it was not a comfortable trip as they had the AC off and the windows up and maintained 55mph. I am sure we could all get better mileage if we slowed down, but where is the fun in that?

 

[Regcabguy]

Tall thin tires please? Again.

Another appeal for 265-275-85-17's. Simple solution.

 

[okayred]

Propane Injection

Propane Injection



I'm surprised no one's posted it yet. I have a propane injection kit (not so cheap, not so hard to install) in my back seat that I have been itching to install.



Technically, the propane mixes with the intake air and gives a more complete burn of the diesel fuel. Plus, the fact that it is flamable gives a HP boost. Tie the two together, keep your foot off the floor and that should give 7mpg (net 3+ after subtracting the price of the propane).



I'll re-post when the system is hooked up.



JP

 

[CFinley]

My Dad has a 03 3500 QC SRW Auto 3. 73 with K&N air filter and Edge EZ and he gets close to 30mpg on the highway. He gets about 17mpg pulling his 35' tavel trailer. I have an 07 2500 QC 6sp 3. 73 with K&N and Quadzilla X-zillaraider and on a recent trip to Arizona and back got a best of 23. 4mpg and a worst of 19. 8mpg with CC set at 70. All those numbers are figured manually cause the computer always shows it to be about 1 to 2 mpg better than it actually is.

 

[p-Bar]

With all due respect, I disagree. In my opinion, nitrogen acts like an ideal gas just like air does. It will change temperature almost as much as air does with a change in temperature.



Gas constant for air is 286 J/kg*K

Gas constant for pure N2 is 296. 8 J/kg*K



If you work out the ideal gas equation (P=rho*R*T) for tires filled with air and N2 at the same initial pressure and same change in temperature, you'll get the following equation:



delta-P_air / delta-P_N2 = 0. 99



So that means that N2 will change its pressure 99% as much as air does with a change in temperature. So if your air pressure changes 5 psi between cold morning and hot afternoon, that same tire filled with nitrogen would change 5. 05 psi. Since most of us aren't using a tire gauge that can resolve 0. 05 psi, that means you would see NO difference in the pressure change between the two gases.



Those who believe nitrogen inflation will reap the benefits claimed by its proponents would do well to recall that air is over 70% nitrogen anyway.



Ryan

Ryan,

I thought it more the size of the molecule, nitrogen being larger than air and the air escaping through the rubber. I think it was more a long term thing, if it ain't flat to the ground then keep driving it. I am not an engineer nor physicist just your every day "Joe the rag man"

 

[JDiepstra]

My Dad has a 03 3500 QC SRW Auto 3. 73 with K&N air filter and Edge EZ and he gets close to 30mpg on the highway. He gets about 17mpg pulling his 35' tavel trailer. I have an 07 2500 QC 6sp 3. 73 with K&N and Quadzilla X-zillaraider and on a recent trip to Arizona and back got a best of 23. 4mpg and a worst of 19. 8mpg with CC set at 70. All those numbers are figured manually cause the computer always shows it to be about 1 to 2 mpg better than it actually is.

And this was in your dream last night or the night before?

 

[Drewhenry]

The Key is Slowing Down

I know it is difficult for most of us to drive under 90 ! Awhile back I made a trip to central Texas from Corpus Christi. I got flipped-off alot for driving 55. I hand calculated a number in the high 20s. It can be done. DRIVE 55!

I don't remember older trucks(pickups)having overdrives. When did the first overdrives appear? What decade was the last terrible gas crunch, long lines at the pump and only able to purchase a limited amount of fuel? Do these coincide?

I'll be the first to admit it is difficult to keep my foot out of it. Also there used to be a great varience in the price of fuel from one station/brand to another. In Corpus Christi, a town of 300,000, all of the diesel costs the same. What happened to competition? And to top it all off most of the fuel being sold is very warm-double screwed with a capital F#@$%!#@$%!#@$%!#@$%!.

I have added an AirDog, will purchase a Smarty before July, and am hoping AAM will produce(or any other gear mfgr) something along the lines of 3. 23. I am debating on ordering the 3. 42s currently available. I am hoping the current crisis causes reason for taller gears. I'd take 3. 07 if available.

I bought this truck for longevity and the stoutness, when fuel was $1. 84.



I also say no more aid to foreign countries that produce/export oil if they won't flow more for all of us. They want corn, wheat, milo, armaments. Fine we trade 100 to 1 for barrels of oil. Maybe even 500 to 1. AND STOP BUYING ***** FROM CHINA#@$%!

 

[rbattelle]

I thought it more the size of the molecule, nitrogen being larger than air and the air escaping through the rubber.

I've heard this argument before, and I don't buy it. We're talking atomic-scale here. Besides, air is 70% N2! So that would imply that, over time, all the O2 and other molecules are going to leak out, leaving nearly-pure N2 in your tires?



Air is not a molecule - it's a mixture of gases. Besides, how do you define the diameter of an N2 molecule? I suppose it's defined as the diameter measured from the nucleus to the outermost electron. But that distance would need to be expressed as a probability, rather than an absolute number.



Personally, I think the argument is nonsensical because once you reach the atomic level the ability of individual atoms to pass through a material is governed more by quantum effects than traditional concepts like "too big to fit".



As for the argument that N2 is drier, it's not clear to me how small amounts (remember air compressors have driers on them) of water vapor will dampen the effects of temperature. The gas constant for water vapor is ~461. 5 kJ/kg*K - 1. 6 times that of dry air. This implies a significant damping effect, but I suspect only near the saturation density (meaning air at nearly 100% humidity).



Ryan

 

[Gary - K7GLD]

What happened to competition?

That one is easy - the bigger guys either bought them out - or FORCED them out of business, the big guys don't LIKE or tolerate honest competition that sells for less, PERIOD!



Much like the bigger trucking outfits actually LIKE the high price of diesel fuel, because it drives their lower charging competition out of business - and they only cry when THEY start being affected by the higher fuel costs and it starts hurting THEM!

 

[CFinley]

Slowing down will help and just cause you have a lot of power, doesn't mean you have to use it. Taking it a bit easier off the start can make a significant difference. Don't get me wrong, I like to romp on it some times too, just not as much since Diesel has been over $4. 00 a gallon, and getting closer to $5. 00 now. #@$%!

 

[thashane]

With all due respect, I disagree. In my opinion, nitrogen acts like an ideal gas just like air does. It will change temperature almost as much as air does with a change in temperature.

Ryan

Ryan,

I think we should start filling tires with pure oxygen. I believe this may be the answer. And given a couple of years, will really start to clear up the problems we're having on the road with poor drivers.





I am just joking btw.

 

[okayred]

Propane Injection or HHO

I just made the trip from Chicago to Panama City, FL in my 12V Dually. I used to have to keep it below 65mph to get 13mpg.



After I installed the propane injection I am getting 19. 5mpg at 65mph. I am going to do a little more tweaking, but for a 4x4 1995 dually, 19. 5 ain't bad.



The 20# propane bottle (used Blue Rino because of convenient exchange) will last for about 16-20 gallons worth of diesel burned - depending on how many hills/how fast I drive. Thats $20 worth of propane for every 350-400 miles not bad...



The system works and it is said to give up to 100 additional hp too. I know that it improves my top-end power significantly.



Plus there is no more soot in my exhaust pipe - only blue smoke comes out now.

 

[AH64ID]

Thats not too bad. . with todays fuel prices that makes you get about 16mpg cost wise. At $20 propane for 400 miles and 19. 5 mpgs.

 

[JDiepstra]

Ryan,

I think we should start filling tires with pure oxygen. I believe this may be the answer. And given a couple of years, will really start to clear up the problems we're having on the road with poor drivers.





I am just joking btw.

What about using at high pressures? The lift in the tires could decrease the rolling resistance significantly and the truck may only feel like 4000 lbs instead of 8000!

 

[thashane]

What about using at high pressures? The lift in the tires could decrease the rolling resistance significantly and the truck may only feel like 4000 lbs instead of 8000!

That's an even better idea! High pressure hydrogen is the solution! Think of the lift provided! We should also make it expensive, but available at costco.

 

[thashane]

I've been debating the removal of the front driveshaft for awhile now, just buying an electric impact wrench and putting it back on when I need it. Except the situations I can't drive out of, are usually the ones where I really would not want to crawl under the truck. Looks like I'm just gonna have to get propane, smarty, and a 10 speed. Is there much in the way for say a 10spd conversion out there? I'm sure there has to be some commercial transmission used on the 5. 9, but with it being that heavy duty I worry about increased parasitic loss. I do not feel a 6spd with a splitter is enough of a gain. So would it be worthe it to look into a 10 spd?

 

[berman2000]

28.5 mpg? whatever your smokin', count me in!

i'd trade my wife for that. ****, i'd throw in my kid too! i run the typical bolt on's, but i do stack (dr performance IV & PPE excelerator). i have 4:10 gears. before mods the overhead console would read anywhere from 17. 5-19, now when i'm on the highway, usually driving between 65-68 mph, i am getting 22. 5-23. 5 mpg. i know this is just the overhead pumpin' me up, but i know i can get over 600 miles on a tank w/ some to spare. no problems. the ol' lady was runnin' her trap about getting rid of the ol' girl. then i told her that the ol' girl is getting better mpg than her honda pilot. she has now commmenced to keeping the ol' pie hole shut. AMEN!