Premium Gas in a 5.7 Hemi

Discussion in 'The Champagne Room' started by SRT-Tom, Jun 17, 2019.

  1. SRT-Tom

    SRT-Tom Full Access Member Article Writer

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    In the July 2019 issue of Car & Driver, the performance and gas mileage of four vehicles which run on regular 87 octane gas were compared to running them on premium 93 octane gas. One of the cars tested was a 2019 Dodge Charger R/T, with a 5.7 Hemi.

    The results showed that there was virtually no improvement in performance or gas mileage when using the higher octane gas. However, the horsepower and torque increased from 318 wheel hp. to 332 hp. and 364 lb.-ft. to 387 ft.-ft. They attributed the increases to the engine controller advancing the ignition timing until it detected knocking.

    Here are the test specifics (87 vs. 93 octane):

    0-60 mph.= 4.9 sec.; 0-60 mph.= 4.9 sec.
    o-100 mph.= 11.9 sec.; 11.7 sec.
    1/4 mile= 13.5 [email protected] mph.; 13.4 [email protected] mph.
    75 mph. fuel economy= 23.2 mpg.; 23.5 mpg.
     
  2. 70-426_10-SRT

    70-426_10-SRT Full Access Member

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    As accepted, but those numbers are all in the NOISE, just like the Political POLLS.

    Unless they did an average of a minimum of 5-tanks each, on the same car, under the exact same temp, road conditions, speed,etc,
    and averaged at least 10 runs each under those same criteria, it is worthless information,
    again, just like the Political POLLS.
     
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  3. IntimidatorRT

    IntimidatorRT Well-Known Member Staff Member Super Moderator

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    been running 93 oct gas in mine ever since I run a tuner on it, I run the 91 tune cause after I had mine on a dyno, the 91 performed better than the 93 tune using the predator. I have been using a trinity with the same settings..
     
  4. SRT-Tom

    SRT-Tom Full Access Member Article Writer

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    Here's how the tests were conducted:

    "We performed acceleration runs, 200 mile fuel economy loops at 75 mph, and dyno pulls, running each vehicle on two different fuels and completely draining the tanks in between. The differences likely would have been exaggerated by extreme summer heat, which exacerbates engine knock, but we sniffed out differences even with engines huffing cool Midwestern spring air."
     
  5. 70-426_10-SRT

    70-426_10-SRT Full Access Member

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    With that logic,
    I could run 87 octane in my 6.1 and trust the stock tune to advance the ignition timing until it detected knocking, no reason for a tuner?
    Well, I'm not going to trust that.
     
  6. B5blueRT

    B5blueRT Full Access Member

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    “ However, the horsepower and torque increased from 318 wheel hp. to 332 hp. and 364 lb.-ft. to 387 ft.-ft.” I guess what I don’t understand is why the mph or elapsed times in the tests DIDN’T get better if the HP and Torque increased
     
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  7. Julie W

    Julie W New Member

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    Same question here....?? How is that?
     
  8. RT2018

    RT2018 Member

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    Ive got the 6 speed and 5.7 and it doesn't like anything but premium.

    Sent from my SM-G950U using Tapatalk
     
  9. HemiFeverAZ

    HemiFeverAZ Full Access Member

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    Now let’s mix it up, cool her down an add hp with meth injection kit


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