turbo engines

Discussion in 'OT Driven' started by imind, May 9, 2006.

  1. imind

    imind i am my own bitch

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    be advised i know very little about cars.

    i have heard that turbo engines use gas more efficiently. does this mean that someone will get better gas mileage? yeah, it depends on how you drive the car, but lets assume that one drives the two cars the same.

    i ask because my mother is getting a new car and is very concerned about gas mileage. she is in her early 50's and is by no means a lead foot, so that 'extra power' is not going to tempt her to drive much differently.


    whats the consensus?
     
  2. RyeLou

    RyeLou OT Supporter

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    all things equal, a turbo SHOULD help on your average OEM car. obviously once you start adding a ton more air you need more fuel, etc. etc.
     
  3. Wolf

    Wolf No one plans to take the path that brings you lowe

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    It burns the gasoline more efficiently, but it also tends to use more gas (especially in city/stop-and-go driving). The biggest impact on improving gas mileage comes from accelerating slower. Turbo cars are great for freeway driving though.
     
  4. Isaac

    Isaac New Member

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    A turbo car generally gets better gas mileage for a few reasons.

    A turbocharger is a device with what are essentially two fan blades attached to a shaft. One fan is in the exhaust system, where exhaust gas blows on it and makes it spin. The other end is in the intake system, and when it spins, it inhales intake air and pressurizes it, forcing more air into an engine, which makes it more powerful.

    If you take a non-turbo engine, turbocharge it, and force twice the air pressure into it asthan it would experience normally, it will put out roughly twice the horsepower.

    The beauty of the turbocharger is that it only operates when you want it to. Driving normally at cruise, a turbo isn't experiencing enough load (from hot exhaust gas coming out of the engine) to spin up, so it doesn't force any more air into your engine. Essentially your engine is operating as a non-turbo engine, and thus burns less fuel. If you floor it, there's enough exhaust pressure to spin up the turbo, it in turn pressurizes the intake air, and you get more horsepower. It also burns more fuel while doing this. It only burns more fuel than a much less powerful non-turbo engine when you're accelerating hard. When you're cruising, it's burning the same.

    Example: Take one two liter turbo engine, and one four liter non-turbo engine. Lets say they both make 200 horsepower. Because the turbocharger on the turbo engine isn't forcing any extra air into the engine when you're just cruising around, it's only burning as much air as a 2 liter non-turbo engine would when you're driving around normally. Meanwhile the 4 liter non-turbo engine, which when floored is giving as much hp as the turbo engine would, is inhaling 4 liters of air and fuel at all times, even when you're just cruising or idling in traffic.

    Hence, the difference.

    But if your mom drives slow anyway, why not just have her get a civic?
     
    Last edited: May 9, 2006
  5. machine81

    machine81 New Member

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    To work off of what was said from above:


    It's not that a turbocharged car gets better gas mileage simply because the turbo is a working component of the engine. If you went outside to the naturally-aspirated car sitting in your driveway and installed a turbocharger you would NOT see an increase in gas mileage. What you would see would be an increase in horsepower and torque. You might not necessarily see worse gas mileage, but you certainly wouldn't see an improvement.

    Part of the reason that people think turbocharged cars are more fuel efficient is because you can install a turbo on a small displacement engine and increase it's horsepower. This makes it easier to drive in most situations. Now, if you're not constantly tapping into this boost (horsepower) you'll just be using the capabilities of the smaller displacement engine and thus be using less fuel. Therefore, a car manufacturer can claim high horsepower when burning lots of fuel on the dyno AND great gas mileage when they are babying the throttle on the EPA fuel economy tests.
     
  6. imind

    imind i am my own bitch

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    funny you should ask that, as that is probably what she will end up with.


    while we're on the subject of gas mileage, is there anything one can do to improve mileage, significantly. i mean beyond keeping it properly tuned, tires inflated, no a/c, etc. i've got a 1980 bmw633 that burns fuel like you wouldn't believe. i joke that you can watch the needle go down while you drive. its not that bad, but you get the idea. i don't want to sell it, but i cannot justify its existence being the guzzler that it is.

    and thanks for your responses regarding the turbo.
     
  7. machine81

    machine81 New Member

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    I was watching Mythbusters the other night and they tested gas-saving devices that could be bought over the Internet. None of them helped. They also said that the EPA closely tracks all the products that could possibly help you save gas. They most significant ones increase gas mileage by around 6%. Basically, don't hammer the gas is about the best you can do to save on gas.
     
  8. P07r0457

    P07r0457 New Member

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    If you look at the window stickers of turbo-charged vehicles compared to their naturally-aspirated counter parts, you will notice three things:

    1) Turbocharged vehicles cost more
    2) Turbocharged vehicles make more power
    3) Turbocharged vehciles get LESS fuel economy

    From a performance standpoint, a turbocharged vehicle is great. From a money standpoint (which is all fuel economy really is -- money) then it's a bad move.
     
  9. keleko

    keleko yes, he is

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    you get less gas mileage - but mostly cuz you're gonna be

    WHEEEEEEEEEEEEEEEEEEEEEEEEEEEEE!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

    most of the time

    :wavey:
     

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