Gas milage

Discussion in 'Motorized Vehicles' started by Jarhead, Oct 10, 2013.

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  1. FSU Logan

    FSU Logan Notebook Evangelist

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    As a pledge, I drive 250 miles a week just being a designated driver... (tank and a half)
    Tallahassee is stop and go and very hilly. I'll take a picture of my MPG if you don't believe me.
    Also being from South Florida, I can attest to that statement. My car is actually pretty below average compared to some of these cars that drive around in South Florida. Feels terrible.
     
    HopelesslyFaithful likes this.
  2. Qing Dao

    Qing Dao Notebook Deity

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    My BMW always got 19-20 MPG regardless of how I drove it. I could baby it around, very gently shift gears, coast a lot, but it wouldn't improve the gas mileage. The only time the gas mileage was any higher than that was on the highway, where it got 29 MPG going at 70-75 MPH.

    The only time gas prices really started to annoy me was in the summer of 2008 when premium was at $5 a gallon and I was driving a lot between my two jobs and doing fun things.
     
  3. Jarhead

    Jarhead 恋の♡アカサタナ

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    So, I didn't really change much of my driving style so I could get a baseline for what my combined city/hwy (20/80, roughly) mileage would be. For a ~90 mile round trip, I used up roughly 4 gallons, so that's roughly 22 MPG combined, which isn't all that bad considering I was averaging ~80mph on the Interstate for the round trip.
     
  4. Tsunade_Hime

    Tsunade_Hime such bacon. wow

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    BMW isn't really meant for fuel economy, and there can be no way that is true. Early shifting, easing off the gas, you should see at least 2-3 MPG vs "normal" driving. And which BMW model do you have? A newer E92 328i should get more then 20 mpg, the base 3.0L inline 6 should get you 23-24 mpg combined if you drive carefully. Keeping around 50-60 MPH on the highway easily nets me 30+ MPG on my now [dead] Integra. I could drive from my house to Browns Mills, NJ AND back [360 mile trip] all on 1 tank of gas which is about 40 for a full tank @ 3.50 a gallon.

    My [dead] Integra used to easily get 30 combined driving very cautiously, but if I floored it all the time, redlining @ 7200 rpm, easily drops to low 10's, like 12-15 mpg.
     
  5. HopelesslyFaithful

    HopelesslyFaithful Notebook Virtuoso

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    i can tell you with my old LHS there wasn't a huge difference unless i drove like a psycho compared to a granny. Normally driving with being heavy on the peddle got me a good 22-24 and if i tried to baby it i got around the same maybe 1-2 MPG more but questionable. Now drving around like a mad man i would get around 18-20 MPG but thats punching and weaving through cars and such.....always ran late to school :) Was such a nice car. I loved the lazy boy type seats in it.
     
  6. radji

    radji Farewell, Solenya...

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    Same thing with my mom. She drives her Camry ~30 miles each way thru gridlock 5 days a week. Runs around a bit on her days off. Usually her fuel economy is ~25MPG. If there is little traffic and she can roll at freeway speeds, that number goes up to ~35MPG.
     
  7. Qing Dao

    Qing Dao Notebook Deity

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    1992 E30 325i manual convertible, 1992 E36 325i manual sedan. There really was no difference. The only things that would change MPG were alignment, tires, and tire pressure.
     
  8. Tsunade_Hime

    Tsunade_Hime such bacon. wow

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    Ah well it doesn't help having a 20+ year old car, unless really kept in tip top shape (changing fuel filter, rotor, cap, plugs, regular oil changes, fuel system cleaning, even ripping apart the block and cleaning out sludge, etc), eventually old cars MPG will dip. I'm sure my Integra new would have gotten even better gas mileage.
     
  9. Teraforce

    Teraforce Flying through life

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    The fuel economy on my 2002 Grand Prix SE (with the 3100 V6) varies widely, depending on how aggressively I drive, how much I drive on the highway, and how much I run the A/C. The lowest fuel economy I've achieved was just under 18 MPG, since I did almost no highway driving on that tank, and I was running the A/C constantly. The highest I've ever achieved was ~29 MPG, and at least 75% of that tank was used on the highway. I typically get anywhere between 18.5-23 MPG on a given tank, since I typically do more city driving than highway driving. My economy has gone up in recent weeks since the weather has cooled off, because I don't run the A/C nearly as much now. The tank on my car can last anywhere between 250 and 400 miles. (280-300 miles average).

    According to the specs, my Grand Prix is rated at 18 MPG city, 26 MPG highway, and 21 MPG combined. I'd say my fuel economy is well within the EPA specs. The only thing that bugs me is the fuel gauge. It doesn't go down at a constant rate; rather, it goes down more rapidly as it gets lower. According to the gauge, I get at least 100 miles on the first 1/4 tank, but then I only get 50-75 miles on the next 1/4 tank, and it only goes down from there.

    Some people were discussing earlier about engine warm-up periods and whether or not they were necessary. The 3100 V6 in my car is notorious for "Piston Slap", which results in clacking sound when the engine is running but isn't warmed up yet. It goes away when the engine is warmed up, which is 100% normal on my engine, but I've read that I should wait until the "piston slap" goes away before I start driving it. It's not MPG related, I know, but there are some engines where letting them warm up first will extend the life of the engine in the long run.

    Agreed with almost everything you said, except for #4, depending on the engine. If your engine knocks on regular gas, then you need to step up to mid-grade or higher. My parents had an 1987 Audi 5000 S years ago, and the owner's manual explicitly stated to only use regular gas, stating that premium would not make any difference. However, we discovered that the car ran noticeably better on premium gas, especially regarding engine knock. Of course, the car was 13 years old and had ~230k miles when we got rid of it, so that might have played a role. There are also some engines out there (like the Toyota 1MZ-FE 3.0L V6) that are advertised as only requiring regular, but they really require at least mid-grade; using regular will cause the ECU to pull the engine timing, resulting in reduced performance (which may or may not be noticeable to the driver). But if your engine runs perfectly fine on regular, and you know the ECU isn't pulling the timing to compensate, then #4 is correct; there is no reason to use anything above regular.

    You don't even need a special MPG calculator to compute MPG. Just follow steps 1-3 in the quote, then simply divide the mileage by the number of gallons used to fill up.
     
  10. Tsunade_Hime

    Tsunade_Hime such bacon. wow

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    Modern ECUs can detect lower grade gasoline and can retard timing if you put lower grade gasoline, you'll just lose like 5-50 hp (depending on your car). Only high end sports cars, turbocharged cars really require premium or higher grade gasoline otherwise you risk engine/turbo damage. I think they tested a newer variant of the Porsche GT2, and on regular gasoline it lost a ridiculous 50 horses.
     
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