Gas milage

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

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  1. John Ratsey

    John Ratsey Moderately inquisitive Super Moderator

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    Here's something useful to read on the subject.

    Note: The numbers use UK gallons but the proportional differences will be the same.

    John
     
  2. Teraforce

    Teraforce Flying through life

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    Most luxury cars require premium gas, too. My dad's old 2003 Infiniti I35 required premium gas, and even then the engine would still knock sometimes, especially in the summertime for some reason (I guess the fuel blends aren't as good in the summer?). Oddly enough, the 2010 Infiniti G37x that he replaced the I35 with doesn't require premium, despite being slightly bigger (3.7L vs 3.5L) and having 73 more hp (328 hp vs 255 hp). It really all depends on the compression ratio. Higher compression ratios=higher octane requirements.
     
  3. radji

    radji Farewell, Solenya...

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    They do retard the timing, just not very well. The OEMs didn't always take into account adjusted timing + lowest grade fuel + punching the throttle from idle = flooded engine. And on the 4 cylinder little put-put engines in these economy cars, that will happen even at moderate throttle increase from idle. I've seen it too many times to count on the V6 company SUVs I worked on.
     
  4. Qing Dao

    Qing Dao Notebook Deity

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    They were both in tip-top shape. The E36's 14 year old, 176,000 mile M50 was the cleanest engine I have ever seen. 3000 mile oil changes and the oil still looking like new? It felt like a miracle. Dyno numbers were perfect. Every time I did maintenance on the engine, I realized that it didn't need it. Anyway, those engines were very advanced for their time and require little maintenance and no adjustments.

    The E30's 16 year old 93,000 mile M20 was something else entirely, and it sorely needed maintenance. When I bought it, the head had recently been replaced after overheating, but I did everything else that could possibly be done without remove the head or taking apart the bottom end. I could tell a little difference in power and responsiveness, but nothing with regards to fuel economy. One of the cylinders did have a small head-gasket leak, which blew a little exhaust gas into the oil. It made the oil turn black pretty quickly, but it didn't seem to affect anything else.
     
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