[ezbentrider]

Since I had my Alternator replaced I have noticed a decease in gas mileage by 1 mile a gallon. I have 5500 miles on my MO and I was hoping it would improve. As it was I was only getting 15.6 miles to the gallon with short trips and a lot of stop in go driving. Now I am down to 14 miles to the gallon. Could the more powerful Alternator cause a decrease in gas mileage?

 

[GripperDon]

Guess it's generating instead of spinning free, that may take some energy. GRIP

 

[hfelknor]

No.


Homer

 

[Eric L.]

Most likely when they replaced the alternator they also disconnected the battery, which reset the computer. The computer needs a little while to relearn your driving patterns for optimal performance.

 

[GripperDon]

AH! Shucks, I liked the making more electrical energy requires fuel idea. GRIP

 

[ezbentrider]

Eric L. response is mostly what's going on and he is right they did have to disconnect the battery and everything was reset. I am not counting on the accuracy of the computer to give me my gas mileage. I remember when I first got the MO it took some time for it to register the gas mileage properly. Thank you everyone!

 

[GripperDon]

Did I tell you the one, about electric powering steering? GRIP

 

[ezbentrider]

Seriously Gripper Don what's going on with the powering steering I saw that you mentioned it on another post. I have a SE 2004 that already had it's alternator replaced now I have to me concerned about the power steering.

 

[crew219]

No.


Homer

Wrong

The whole purpose of an alternator is to convert mechanical energy to electrical energy. Alternators do not produce a stated amount of energy at all times. They produce power based on how much load is on the system and adjust the resistance accordingly. That amount of resistance is driven by the accessory belt which is then in turn driven by the accessory pulley which is powered by the crank. Thus if you have a more powerful alternator, you will see greater fuel consumption. Same goes with increasing the amount of load on the alternator.

If your alternator was failing, then it would be spinning freer than normal (low-resistance). By switching back to a normal new alternator, it has a greater resistance (because its working) than the failed one. If the alternator itself is "upgraded" (producing more amps), it will draw even more mechanical energy in order to produce electrical energy.

For instance, a smaller output alternator that produces 100amps can produce 90 amps at less resistance than a 150 amp alternator producing 90 amps because it has less mass to drive (generally higher-output alternators are larger). However, there are also companies that increase the output of the same stock sized alternator by varying the winding & quality of the materials involved. Thus its possible to have higher output from the same sized alternator. However since OEM is generally whatever is cheapest to get the job done, auto manufacturers increase the size of the alternator if they need more output.

Dave

 

[GripperDon]

OK Here we go, Crew219

Dave

Glad YOU got the point, it IS RIGHT, to say that it takes gasoline energy to produce the electrical energy from the Alternator to charge the batter and supply the other needs of the vehicle, and we all know that the load varies.

The mileage you could get during the short time the alternator was failing would be the higher value because of using the energy stored in the batter that was not being replaced by the alternator. I was actually being IMHO funny as it was a kind of silly observation, However Dave elaborated to make it a more detailed examination of the situation, GO DAVE GO.


NOW FOR THE ELECTRIC POWER STEERING.!

Briefly, When I ran the Mechanical Department of the Bendix Research Labs, one of the thing we developed, way back in 1974 was "Electric Power Steering" The advantages were:

1. Full power all the time even engine off!
2. Full control of assist ANY way it was desired, vs speed, etc.
3. Improved fuel economy, no drive belt etc.
4. A bunch of others: Packaging , Cost, Increased flexability of under hood positioning.
GRIP

 

[zebelkhan]

And disadvantages? Sounds like something that should have been used on cars.

 

[GripperDon]

Once the Drive belt goes away and we have electric: AC, PS, etc. the advantage can be maximized and one more thing they are changing the auto voltage from 12 to a higher number (yet to be finalized) this will further maximize the effectiveness and allow integration of the starter / alternator all in one package. They are just slow getting things done in MO town (pun)

 

[revhigh]

Is it possible that your area recently changed to the oxygenated gas that's used in some locales in the winter?? That always reduces my MPG by about 10 %

Just a thought ...

REVHIGH !!!!!!!!!

 

[zebelkhan]

Is it possible that your area recently changed to the oxygenated gas that's used in some locales in the winter?? That always reduces my MPG by about 10 %

Just a thought ...

REVHIGH !!!!!!!!!

You know...that could definitly explaine the sudden reduction in my gas mileage. I never though of that possibility. Thanks.

 

[GMTURBO43]

Another thing is the engine warms up slower - it will be running rich for a longer period of time. It'll also idle higher for a longer period of time.

 

[GripperDon]

And it's got to put out those increased amps and that takes some energy and thats moew gas. Considering it probably only tahes around 30 hp to go 60 mph. Those extra amps add up.