Motachanic: Does a Kickin' Amp Cause an Decrease in MPG?
We have now a Motachanic! He will be here to help me out and answer the gear head type questions that make my eyes cross and help out anyone who is having issues with their ride. You can always ask questions of either one of us through my email in my profile. XOO,M!
Dear Paolo,
Thank you for writing. Your amplifier can cause poor gas mileage in your Integra. I will explain why this occurs and also some ways to alleviate some of the lost gas mileage.
First off, all of the electrical and electronic devices in your Integra are powered by the alternator when the engine is running. The alternator is what converts mechanical energy from the auxiliary drive belt into electrical energy that is used by the engine and accessories.
The alternator in your car is rated at a certain amperage to be able to run the engine (spark plugs, ECU, various sensors, etc) and all of the accessories in your car. (radio, windshield wipers, lights, windows, radio, etc)
However an aftermarket amplifier draws more power that the stock sound system. I believe the stock sound system in your car is a 120 watt system. However if you have a 500 watt amplifier installed then it is drawing over four times the power of the stock system. (Wattage divided by voltage equals amperage. So the stock sound system is using 10 peak amps and the amplifier is using 41.6 peak amps).
Having this much power being used does several things, it lessens the available power for other electrical components, it shortens the life of the alternator, produces heat, and causes resistance. These are all bad things. If there is less energy to go around and the alternator is already running at peak capacity then the difference will be split between the loads and the sources (battery and alternator). This means that not only will your amplifier be unable to produce its rated output, but the ignition system will be starved for energy and will produce a weaker spark. A weaker spark means that less power is produced by the cylinders which means less gas mileage.
Additionally, the more electrical load there is, the more mechanical resistance there is. This means that the engine has to work harder to turn the alternator thus using more fuel (kind of like when you turn on the air conditioning in your car and gas mileage goes down)
You can install an after market alternator that is capable of sustaining higher amperages than the stock one which will alleviate the short life span and weak spark problems., but the only thing that will return your gas mileage to what it originally was is to leave the amplifier off or remove it from your Integra.
If you have any further questions, feel free to ask.
Sincerely,
The Motachanic
Stumble It!
Dear Motachanic,
Is it true that my system that I put into my Integra is draining my MPG? I put in a 600 watt amp. My friend said that the drain on my alternator will drain the amount that my car gets per gallon. Thanks,
Paolo
Dear Paolo,
Thank you for writing. Your amplifier can cause poor gas mileage in your Integra. I will explain why this occurs and also some ways to alleviate some of the lost gas mileage.
First off, all of the electrical and electronic devices in your Integra are powered by the alternator when the engine is running. The alternator is what converts mechanical energy from the auxiliary drive belt into electrical energy that is used by the engine and accessories.
The alternator in your car is rated at a certain amperage to be able to run the engine (spark plugs, ECU, various sensors, etc) and all of the accessories in your car. (radio, windshield wipers, lights, windows, radio, etc)
However an aftermarket amplifier draws more power that the stock sound system. I believe the stock sound system in your car is a 120 watt system. However if you have a 500 watt amplifier installed then it is drawing over four times the power of the stock system. (Wattage divided by voltage equals amperage. So the stock sound system is using 10 peak amps and the amplifier is using 41.6 peak amps).
Having this much power being used does several things, it lessens the available power for other electrical components, it shortens the life of the alternator, produces heat, and causes resistance. These are all bad things. If there is less energy to go around and the alternator is already running at peak capacity then the difference will be split between the loads and the sources (battery and alternator). This means that not only will your amplifier be unable to produce its rated output, but the ignition system will be starved for energy and will produce a weaker spark. A weaker spark means that less power is produced by the cylinders which means less gas mileage.
Additionally, the more electrical load there is, the more mechanical resistance there is. This means that the engine has to work harder to turn the alternator thus using more fuel (kind of like when you turn on the air conditioning in your car and gas mileage goes down)
You can install an after market alternator that is capable of sustaining higher amperages than the stock one which will alleviate the short life span and weak spark problems., but the only thing that will return your gas mileage to what it originally was is to leave the amplifier off or remove it from your Integra.
If you have any further questions, feel free to ask.
Sincerely,
The Motachanic
Labels: Buying Cars, repair
Stumble It!
posted by Miss Mota Mouth@ 5:59 PM 3 Comments
3 Comments:
Wow, I actually understood that answer.
Can it lessen your MPG, MAYBE. Most of the time what actually lessens the MPG when you have a huge system is all the weight of the amp, the subs and the box they're in. You can put a light weight system in a car and notice no difference in the MPG.
re: Jaeryn
Absolutely, the extra weight adds to the problem. The more weight the engine has to push around the more fuel it will use. A 500 watt amp is a pretty mild stereo mod and shouldn't be too heavy which is why I didn't address it but you are absolutely right.
However, running any electrical device in a car will lower the MPG, regardless of whether it is off-road lights, a sound system, or whatever. The laws of physics are what they are. Whether or not the owner notices the change is based on their perception. Typically when using electronics in a car the change is so tiny that you wouldn't notice, but as the electrical load increases MPG decreases.
Grimy Handshakes
The Motachanic
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