5MPG Gain Possilbe?

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[quote author=ppc link=board=2;threadid=11597;start=msg107118#msg107118 date=1077161331]
One time, in band camp, i drove with a big wind behind me and I had to keep stopping to drain gas out of the tank because it kept overflowing. How do I calculate MPG for this?
[/quote]

Hey Phil,

Can I have some of whatever you had? ;)
 
[quote author=Beowulf link=board=2;threadid=11597;start=msg107174#msg107174 date=1077168983]
Steve,
Have you factored in the 6% difference in the odo? You actually travelled farther than your odo measured unless you've recently installed the correction gear in the transfer case.
-B-
[/quote]

Actually yes, but I just corrected for it. The miles that appear to be traveled are equal to the ratio of the old diameter divided by the new diameter. Mine had 31" stock, and I went with 33's. That's a 6% difference. So multiply by 106% or 1.06, and if I'm at an indicated 12 I actually got 12.36. This applies to speedometer as well - although a better check is to use the green milepost signs to determine how far off you are - check several of them though.
 
12.72?
 
[quote author=e9999 link=board=2;threadid=11597;start=msg107724#msg107724 date=1077256909]
12.72?
[/quote]

Duh. You're right.
 
[quote author=IdahoDoug link=board=2;threadid=11597;start=msg107185#msg107185 date=1077170432]
Stuff that would reduce MPG:

Our lights are always on


DougM
[/quote]

WTF Does this have to do with gas mileage? Added drag on the alernator causing resistance to the engine therefore causing more fuel consumption to run the lights? Sounds like some chit the geezer snowbirds in Phoenix would come up with to dispell the rumors that daytime running lamps reducing accidents is a good thing.
 
what the ****?
I won't address the tone of the above reply by Bman, but I can't resist mentioning that is plain obvious to most that the energy used to run the lights -namely electricity- has to come from somewhere and that's the engine. :slap:
So of course it decreases the mileage! what, you think the alternator is running like a windwill, maybe?
sheesh....
E
 
[quote author=BMAN link=board=2;threadid=11597;start=msg109198#msg109198 date=1077579098]
WTF Does this have to do with gas mileage? Added drag on the alernator causing resistance to the engine therefore causing more fuel consumption to run the lights? Sounds like some chit the geezer snowbirds in Phoenix would come up with to dispell the rumors that daytime running lamps reducing accidents is a good thing.
[/quote]

And you are???? Nice to meet you too :flipoff2: Go get your aggression out on Pirate, then post here when you're ready to be nice :slap: Junk is the only one who can come out of the blue with that kind of attitude and not catch any flak.
 
MR BMAN,

Your post was in poor taste. Please go back to Pirate and come back when you can be a little nicer. :doh:
 
Bman,

Um, yes. You got it exactly right except for the snowbird part. The energy for your truck to do everything from light the dimmest bulb in the dash to the BTUs coming out of the heater comes from one source: gasoline.

DougM
 
1ST I will appologize to all of you whom I offeneded with my wrye comments. Yes, I am a regular on Pirate. No, this fact does not weigh in any way on the attitude I have when posting anywhere on the internet. Yes, I am a regular on IH8MUD although I am mainly a lurker here. I frequent many BB's on the net and this is one of them. Anyone who knows me will know that this appology is very much out of character for me but I do it because I respect Woody and everything he does for the LC following by making this site available for us. I have taken alot of things I learned here and used them to make my rig what it is. IH8MUD is a wealth of knowledge and I recognize that fully. MAybe next time I will use one of these :flipoff2: which I hope means the same thing here as it does on Pirate.

Now back to my comments. Although I have not done any research on the subject specifically I believe that the orginal staement is unfounded. I do not believe that running your lights causes your vehicle to burn more fuel than it would if they were not on. I would argue that your alternator is constantly creating power when the motor is running and that power is either used or stored regardless. I would also argue that no measurable amount of drag on the alternator is created when the lights are on and therefore the engine of your vehicle does not labor any more than with your lights off. If the engine is not laboring more then there is no reason for it to burn more fuel. Again I will state up front that I have not done any reasearch, personal or otherwise, on this subject but it is deffinately something that has caught my attention and now I intend to prove myself right or wrong.
 
Bman,

The alternator only produces as much "power" as the electrical system demands to function as spec'd. The lowest consumption would come with all "appliances" off a fully charged battery. In this situation the only systems requiring power would be the ignition and various ECU's (well the "p" light in the dash"). When any "appliance" is turned on it asks the alternator to provide more power, there by increasing the drag.

Do you feel the a/c on/off effects the gas mileage? The pully is always turning whether the clutch is engaged or not?

I don't think anyone is implying the 5 mpg is going to come by turning the lights off, maybe .05mpg.

andre
 
Thats it we are dumping the alternator and puttint 10 dry cells in the back, just plug in every night (LOL).

I guess this would not be the solution, however I still feel strongly that the ignition system could greatly improve along with newer new or rebuilt injectors.

Hey CDan, how much for plug wires, rotor, injectors and a factory manual. Oh and while were at it that funky tool for the rear FF that you spoke of in another thread?

Also is it possible to make the 80 a part time four wheeler?

Lastly, this engine will give a maximum fuel improvement of maybe 2-3 MPH by the sounds of it. The 1HD-FT I have heard will maintain 26MPG highway without being to throttle cautious. The 1HD-T will achieve about 22MPG, still nothing to bock at. Hard to believe 4MPG difference between a engine with twleve valves verses 24 valves?

Thanks for the input.

Rob
 
Bman,

Nice reply. As for the relationship between electrical load on the alternator and fuel mileage, there is little debate that added loads equal added fuel use. As I noted above, absolutely everything your truck does for you takes power to accomplish. Even clicking on the maplight drains a tiny bit of electricity that the alternator must replace in the battery. I'm sure there's a simple formula somewhere that converts a 12V 1 watt load backwards into a unit of gasoline energy using some standardized alternator's efficiency in power generating.

When I worked at GM, I recall the debate over DRLs and the decision being made to develop a special circuit so that only the headlamps would illuminate for the DRL function rather than simply switching on the vehicle's lights (which would include the side markers, parking lights, dash lights, tail lights and license plate lights). Developing and installing this additional circuit cost GM millions of dollars but the result was a very tiny improvement in their overall fleet fuel economy (CAFE).
 
1hp = 746 watts,

an alternator is probably only 70% efficient at turning shaft HP into electricity
 
BMan, sorry buddy, but you are just plain wrong as far as the lights not possibly decreasing mileage. One could conceivably argue that the effect is small, but as far as the basic principle, the basic laws of physics are immutably against you. (Not that that ever stopped some of my students... :D)
E
 
BMan,

Think about it this way:
Does added load on the alternator translate into more resistance against turning the pulley, therefore making the engine work harder and burn more gas?

Unless the resistance of turning the pulley on the alternator is absolutely constant (in regard to what the alternator is having to do), then using the lights will burn more gas. More work required by the alternator means more energy that has to be put into it by the engine.

It seems like you're thinking that the alternator pulley requires the same amount of force for the engine to turn it, no matter how hard the alternator is working. I don't think that's true.

That's why I'm leaving my license plate bulbs and dash indicators burnt out - I'm helping prevent crisis in the Middle East. :flipoff2:
 
[quote author=raventai link=board=2;threadid=11597;start=msg109596#msg109596 date=1077646007]
1hp = 746 watts,

an alternator is probably only 70% efficient at turning shaft HP into electricity
[/quote]

True about the 1 hp = 746 watts. You can see this in the double rating of KW/HP where KW is about 3/4 the HP. Would a 22r hold an 80 at 75 mph on the freeway? I think not. Let's assume 100 hp is required - Naw, let's make it 50 hp to be conservative. How powerful are headlights? 55 Watts each? 50 HP * 746 = 37,300 Watts. 110/37,300 = 0.003 of the fuel used -


Call the alternator 50% efficient and you have 0.006 of 15 mpg, or 0.1 mpg.


Steve H
 
BMAN,
Nice entrance. :D
-B-
 
Well it seems after hours of exhaustive research (downed a few Dundees in front of the computer). I have found that I am a total Clownshoe and my understanding of automotive functions and engineering is rivaling that of my three year old daughter. Steve H is pretty much right on with his figures(not sure about the HP# but I'll go with it for now) which prove that although negligable electrical accessories do affect gas mileage. I will now always drive with my lights off (hope that guy in front of me at night doesn't get pissed when I tailgate him so I can see the road) and I'm takin the radio out of my truck this weekend.

Beowulf,
Graceful...ain't I?
 
<<< "and I'm takin the radio out of my truck this weekend" >>>

:D That's pretty damn funny :D You got off on the wrong foot but made a great save ;)

Don't forget to disconnect the brake light stitch too 8)
 
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