fuel economy
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Northstar Engines and System Technical Discussion Discussion, fuel economy in Cadillac Engine Technical Discussion; Hey all im sure you all know about how the gas mileage of the V8s are, if i got a ...
  1. #1
    capn's Avatar
    capn is offline Cadillac Owners Fanatic
    Automobile(s): 94 Eldorado ETC
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    fuel economy

    Hey all

    im sure you all know about how the gas mileage of the V8s are, if i got a hypertech programmer could i somehow adjust it to get better fuel economy like 20mpg or more?

    capn

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  3. #2
    BeelzeBob's Avatar
    BeelzeBob is offline I'm a Cadillac Fanatic!
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    Re: fuel economy

    Quote Originally Posted by capn
    Hey all

    im sure you all know about how the gas mileage of the V8s are, if i got a hypertech programmer could i somehow adjust it to get better fuel economy like 20mpg or more?

    capn
    The engines are pretty well optimized for fuel economy. The combination of spark advance, EGR supply and closed loop fuel control ensure that the engine is operating most efficiently all the time. It is highly unlikely that you are going to jimmy something with the hypertech controller that will cause better fuel economy.....

    The main thing that governs fuel economy is the mass of the vehicle and the way that it is driven. "V8's" get poor economy...???....not really unless you put your foot into it all the time....!!! The V8 isn't the problem....the acceleration that feels so good is what costs fuel economy. In town it is going to be hard to get 20 MPG on any car the mass of an Eldo but you should easily get well over 20 on the highway with your car. If not, then there is nothing that a hypertech controller can do to help it.

    Even if it could, consider the cost of the aftermarket controller and how much fuel you could buy with that money and how far it would take you. Probabably little or no business case for the aftermarket controller even if it did work.

    Do you have a 4.9 or a Northstar engine??

    If you have a 4.9 make sure that the EGR tubes under the throttle body are clean and use a timing light to bump the timing up 2 or 3 degrees. Those two things will do more to ensure you are getting the best economy than anything else.

    With the 93/94 Northstar the intake needs to be removed and the phenolic spacer plates cleaned thoroughly to make sure the EGR system is flowing correctly. That , and run good gasoline in the engine. The Northstar has a very effective knock control system that will retard the spark advance to prevent detonation which will hurt the economy some. Run premium fuel to make sure that this is not a problem to get the best fuel economy.

  4. #3
    capn's Avatar
    capn is offline Cadillac Owners Fanatic
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    Re: fuel economy

    i have the 94 4.6 northstar, and i ran it through a scan tool and got some codes i forget the number but it was somehting like EGR pipett malfunction and some others, i should have wrote them down and i do alot of highway driving and im getting like 16.5 mpg but maybe like once a week i gas it to show a ricer whos boss other than that i drive like a grandma only going up to 2,500rpm

    and in NC we only have 87 89 asnd 93 octane and since it is recomended that you use 91 i have to use 93 so i should be getting better fule economy right?

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