System taking lots of power quick question
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Bronze Member Username: ForcesofchaosPost Number: 61 Registered: Sep-04 | well i only got my car a little bit ago i filled up the gas tank full reset trip and by the time it got almost half way gone i had about 190miles on it so its about 23mi per gallon well then i got my system in when it was half full and i went like only 90 miles and its already below the 4th way mark. Usually when i hold the gas pedal down by the time my rpm reaches 4 it would be up to like 90mph now its only like 40 and its in the 5 (begiining of red) so the sytem like cut my gass millage in half. Well is there any way to get it back up so i get better millage? capacitor maybe i dont know. 2 adire shivas powered by a kicker 600.1 with high level input and factory deck. |
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Silver Member Username: Pat_lTucson, AZ USA Post Number: 648 Registered: Apr-04 | Last time i looked a Car Audio System is powered by electricity not gas. |
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Silver Member Username: FishyTamarac, FL USA Post Number: 465 Registered: Sep-04 | Actually it is powered by gas when the engine is running. Where do you think your alternator gets its power from? Regardless, your alternator might be bleeding a bit more hp off your engine but not enough to reduce your gas mileage by half unless your driving a moped or somethin. And btw 90 mph at 5000 rpm is gonna be 90 mph at 5000 rpm no matter how bad your engine is doing unless you're in a different gear. Maybe your tach/speedo is fubar. Whatever the case, sounds like you have problems. -Fishy |
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Bronze Member Username: ForcesofchaosPost Number: 62 Registered: Sep-04 | heh well its a old car 1990 bonneville. System uses lots more alternator power which in time decreases gas mileage because it works harder to power the car. well like i said first time i filled gas up it could be the gas indicator thing is not accurate which could make it look like this. first time i got the car it was half full and it went down fast i think maybe i get less miles per gallon then i think. i think your probly right that it couldnt cut it in half thats ridiculous its a 6 cylender engine so ill see if i can find the acutal Mi/G online to see what im supposed to get and then maybe unplug system till i see what the car gives me. theres other factors how fast you speed up or slow down and other things. As for the system uses more power which requires moer alternator power during speeding up. Ill check it out. 1 quick question how fast you think a 600rms power amp could run straight off a battery? Could i get a second battery and connnect the sub straight to it and not have the alternator supply any power? i would have to connect ground to other side of battery but that would be easy enough. just put it in the back. maybe i could connect it to alternator when it dies to recharge it? Thoughts, suggestions thanks. |
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Silver Member Username: FishyTamarac, FL USA Post Number: 466 Registered: Sep-04 | A 600w rms sytem will draw around 60 amps at full power. Mosts systems don't run constantly at full power though. You can get a pretty rough estimate however from what your battery is rated in amphours. A fully charged 120 amphour battery can theoretically deliver 60 amps for 2 hours, but I wouldn't test this theory unless you have a deep cycle battery on your moped.  -Fishy [note] if you wanna see the effects your system has on gas mileage there's no need to disconnect your sytem. Just don't turn the thing on for a tank full. |
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Gold Member Username: GlasswolfNorthWest, Michigan USA Post Number: 4480 Registered: Dec-03 | trust me, you're not using that much power for the audio system. 1 horsepower will produce around 737 watts of power, so really even with a 3Kw system, at full output, you're only drawing a few horsepower from a motor that produces well over 100HP I'd hope. now that's at full output, which is full folume, and driving a full spectrum pink noise signal from a signal generator. That won't happen much. Every time you decrease that full output by half, you're using a tenth of the power, so a 1000 watt system (RMS) at half volume is only using an average of about 100 watts of power. Drop that to a quarter of the volume and you're down to ten watts of power usage. |
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Silver Member Username: FishyTamarac, FL USA Post Number: 472 Registered: Sep-04 | Actually 1 HP is exactly equal to 746 watts. http://auto.howstuffworks.com/horsepower1.htm an "average sedan" requires about 20 hp to cruise along at 60 mph(plug in 60 mph here). http://www.bgsoflex.com/aero.html So any audio system that sucks a constant 1 hp(746 watts of pink noise? lol) could theoretically reduce highway gas mileage by 5%. Of course there's alot of losses involved in the belt/alternator/amplifier system so I'd guess that figure might go as high as 10%. Of course nobody plays their stuff that loud for that long, at least I don't think they do and still retain moderate hearing capabilities. -Fishy |
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Silver Member Username: Motoman22Dallas, Texas USA Post Number: 103 Registered: Dec-03 | Tyson, just fill your tank up and reset your trip odometer. Drive around until you are low and fill it back up (same gas station, let the pump stop itself both times and don't top it off.) See how many miles you went on how many gallons. If you think your system has something to do with it, go a tank without using your radio, it's not having an effect I can assure you.... not one you can measure in fuel usage anyway (unless you count down to the cc's of fuel used every time.) |
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Silver Member Username: Motoman22Dallas, Texas USA Post Number: 104 Registered: Dec-03 | "Usually when i hold the gas pedal down by the time my rpm reaches 4 it would be up to like 90mph now its only like 40 and its in the 5 (begiining of red)" Redline at 40mph, sounds like it's stuck in first gear... |
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Bronze Member Username: ForcesofchaosPost Number: 63 Registered: Sep-04 | as the last thing *Redline at 40mph, sounds like it's stuck in first gear...* i probly overestimated that but i think your right i think its just my gass odemeter its kinda screwy when its full its over the full mark by a whole 1/4 tank distance. so im thinking that it just goes down faster when its lower plus i went more miles then i thought though i still think it cuts it down about 1-3 miles per gallon but i dont think its that bad anymore ill see how much it fills up the next time i go so far the trip odometer is at about 270miles so its good i hear most of these cars gets about 275-300mi per tank <19-23mi> so i hope its all good. |
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Bronze Member Username: CtxPost Number: 74 Registered: Jun-04 | sounds like a really dirty fuel filter,or bad fuel sensor |
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Gold Member Username: GlasswolfNorthWest, Michigan USA Post Number: 4523 Registered: Dec-03 | Fishy, 746 watts is without factoring in any loss, which is why i said around 737. also, I was referring to the drain of the audio system itself. the car's own systems will use current in addition to this for the spark plugs, battery charging, lights, gauges, etc of course. point is, at normal listening levels, you're probably only using about 20 watts of total power continuously, which is going to draw less than 1HP from your motor via the alternator supplying the current. end result is that a stereo system won't affect your gas milage all that much. he has other problems. just for fun... Kilowatt (kW) A unit of electrical power equal to one thousand watts. HorsePower (hp) Unit of power in the English system for measuring the rate at which an engine or other power source can perform mechanical work. One horsepower was originally defined as the amount of power required to lift 33,000 pounds 1 foot in 1 minute (This origin as to do with the Industrial Revolution when they replaced horses with Steam Engines). Brake HorsePower (bhp)The power output of automobile engines is quoted in brake, or shaft, horsepower--that is, the maximum theoretical horsepower of the engine minus the power lost through heat, friction, and compression. This Brings us to the Issue of Converting Between a bhp and a kW The Key Value is how many pounds per foot per second can be moved with each unit. Power Conversion Factors 1 watt (W) moves exactly 745.6999 pounds one foot in one second 1 horsepower (hp) moves exactly 550 pounds one foot in one second [Multiplier for Kilowatts to Horsepower] 745.6999 (ft-lb/sec){1 watt} / 550 (ft-lb/sec){1 HorsePower} = 1.355818 [Multiplier for Horsepower to Kilowatts] 550(ft-lb/sec){1 HorsePower} / 745.6999 (ft-lb/sec){1 watt} = 0.737562121169655514235686500695521 |
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Silver Member Username: FishyTamarac, FL USA Post Number: 478 Registered: Sep-04 | lol your right, that lil worksheet probably gives you the required BHP or brake horse power(hp at the wheels) required to overcome aerodynamic drag and rolling friction. The required shaft HP, or horsepower measured at the flywheel, would actually be a bit higher due to losses in the transmission, rear end, etc. I do think using a HO alternator may reduce your gas mileage slightly tho. Mine has a much smaller pulley than my stock one which can cause the belt to "chirp" when my stereo is cranked when accelerating from idle. Ever wonder why "gearheads" go for larger component and smaller flywheel pulleys in their quest for more horsepower? Its so their alternators, power steering pumps, etc. don't self destruct at high rpms, but its also so they don't bleed as much horsepower. Electric cooling fans are another example. -Fishy |
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Silver Member Username: Pat_lTucson, AZ USA Post Number: 652 Registered: Apr-04 | Not to stick it in anyones face but that is why i originaly said that Car audio is powered by electricity, not gas. Because a system wouldnt be able to take that much off his gas mileage |
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Silver Member Username: FishyTamarac, FL USA Post Number: 480 Registered: Sep-04 | Yeah but that electricity is developed from the energy in your gas tank, but you're right. Your system's effect on gas mileage is gonne be minimal. I got a trip to Atlanta comin up. I keep a pretty sharp eye on fuel mileage on long trips. We'll see if my new alternator affects anything. It probably won't since I don't plan on cranking my stereo for 10 hrs straight, but we'll see. I wouldn't be surprised if my HO isn't as efficient as stock. -Fishy |
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Gold Member Username: GlasswolfNorthWest, Michigan USA Post Number: 4540 Registered: Dec-03 | well, the pulley sets aren't really designed to stop anything from blowing up, but they will increase efficiency a bit yes. Actual gain is only a few horsepower even on a big V8, but I suppose it's more noticeable on a little four-banger. I'm running over 550HP so it's not really much of a concern to me running a 270A alternator. I don't notice the drag on the engine to be honest. I did run a 150A lestech alternator in a Festiva though and that didn't feel much different either to be honest, and that car had all of about 68HP to start with. I probably felt more diminished response due to the 200lbs or so of gear than I did from the drag of the larger alternator which came out of an ambulance. anyhow, again it sounds more like he has other issues causing his diminished performance. My best suggestion would be to take the car into a garage and have it hooked up to a diagnostic computer, and have them read the onboard computer of the car. See what's going wrong. Cost ya about $50 I'd think, and should tell ya everything about the car. At least you can do that on anything after about 1980 or so. couldn't do much with my car but mine's older than I am. haha |
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Gold Member Username: GlasswolfNorthWest, Michigan USA Post Number: 4541 Registered: Dec-03 | oh, just for reference, if you want to get a rough idea of horsepower at the street, take the flywheel HP and subtract about 20%. vice-versa to go the other way, from street to flywheel. |
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