Nitrogen and Alcohol

[Stephen Locke]

Thought I'd ask for feedback on a couple vehicle dilemmas.

Nitrogen vs Plain Old Air for tires.

and

10% Ethanol vs Plain Old Gas for your motor.

What are you guys and gals running and why?
What are the practical advantages and disadvantages?

 

[David Wolfson]

Ethanol has an energy content of about 76k Btu/gallon vs. gasoline's 109k Btu/gallon. Modern engine technology adjusts the carburetion automatically for the proper air-fuel mixture, which negates the main reason oxygenated fuels were promoted starting about twenty years ago -- to reduce CO and HC emissions. Ethanol is a "renewable" source and the CO2 produced by its combustion theoretically gets recycled rather than accumulating in the atmosphere; however its production uses energy, much of it from fossil fuel sources. Ethanol's net energy content (allowing for production) is around 25k Btu/gallon.

Bottom line: loss of around 3% mpg/10% blended, some reduction of atmospheric CO2 accumulation, and little effect on vehicle performance.

AFA N2 in tires, read here: http://blogs.consumerreports.org/cars/2007/10/tires-nitrogen-.html

 

[Greg Campbell]

Nitrogen is 'nice,' but makes zero difference if you check the pressure once or twice a month. (Be sure the tires are truly cold, and re-check when ambient temperatures change markedly) Even if filling with plain air, the nitrogen concentration tends to self-enrich after a few top-offs.

The bigger question is 'what pressure to inflate the tires.'
Handling, tire wear, fuel economy, and hydroplaning resistance are all improved by running higher pressures. Dry grip may decrease slightly.

Keep in mind that the door-frame numbers on your car represent a compromise between engineering requirements and a nice cushy ride. FWIW, my older Honda wagon wears the tread edges badly at the stock pressure of 32 PSI. The tires really need ~36PSI in the front, and a hair more in the rear, to properly support the car. I've been running 40/41 PSI for the last few years with zero negative effects. (Going much higher rapidly degrades the ride quality.) As near as I can tell, the extra pressure gets me about 1.5 extra MPG at freeway speeds, a little over 4%.

As David points out, gasohol does little except reduce the fuel's caloric energy per gallon.


(Stephen, if you find this advice useful, please box up that unloved 5x7 camera of yours and send it my way! )

 

[D. Hayes]

Truth be told with E85, it really depends on what vehicle you drive. Many of my fellow F150 drivers (F150online.com) tested E85 in real world driving on their capable trucks when it really started being pushed into the market. Many found that E85 was cheaper but their mileage went down to where the price difference wasn't worth the loss. Several also mentioned loss of power, not something truck owners want.

Far as N2, pointless was of money. We use it in aircraft tires where temps change drastically with altitude. It keeps the tire pressure stabilized and keeps moisture out of the tire which could freeze and damage the tire.

 

[Jason Foster]

Truth be told with E85, it really depends on what vehicle you drive. Many of my fellow F150 drivers (F150online.com) tested E85 in real world driving on their capable trucks when it really started being pushed into the market. Many found that E85 was cheaper but their mileage went down to where the price difference wasn't worth the loss. Several also mentioned loss of power, not something truck owners want.

Far as N2, pointless was of money. We use it in aircraft tires where temps change drastically with altitude. It keeps the tire pressure stabilized and keeps moisture out of the tire which could freeze and damage the tire.

I used the e85 during my 2006 storm chasing a few times. I agree that the MPG/cost ratio isn't there, but I LOVE the fact of keeping the money in the states as much as possible...which is well worth the few pennies lost per gallon.

 

[Mark Blue]

I'm one of those that pays a premium at the pump and only buy the highest octane fuel for whatever brand I'm purchasing. I mostly stick with Shell, P66 and Conoco, except when we are out of town. As far as I'm aware you need to have an engine that is designed to run E85 before you do so otherwise it can have some negative effects on your fuel system, or at least that's what I've read in Car and Driver. The fuel in Denver is blended with MTBE in the winter months (probably all year now) to help with the brown cloud. I used to notice a small difference when the oxygenated fuel was being used in that it smelled funny and didn't provide as good of mileage as the fuel without the additive. My engine also idled better when using the pure fuel.

As far as using anything other than air in my tires I have no useful advice to give you. My wife bought me a compressor a couple of years ago so it's nice to be able to do it at home versus plugging those stupid gas station pumps with 75 cents every time you need air.