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87 vs 91

Discussion in '2nd Gen. Tacomas (2005-2015)' started by nd, Mar 22, 2007.

  1. Mar 22, 2007 at 7:08 AM
    #1
    nd

    nd [OP] Radical Town. It's a hell of a place!

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    Hey everyone, this is my first aside from my introduction. I have a quick question. When researching 2nd gen tacomas, this biggest complaint i found was that the 05 and 06 models with V6 run on premium gas, and the performance suffers greatly if you use the cheap stuff. I just recently bought an 07 and was told it was ok to use the cheap stuff. I have filled her up with 87 and 91 to see if i could tell a difference. I was wondering if anyone had any feedback on the subject. Also, there is a loss of about 10hp and 15ft/tq from 06 to 07, is this explained by the ability to run on cheaper fuel? Any feedback would be appreciated. Thanks
     
  2. Mar 22, 2007 at 8:07 AM
    #2
    TRDeity

    TRDeity Well-Known Member

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  3. Mar 22, 2007 at 9:58 AM
    #3
    CasaTaco

    CasaTaco Active Member

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    My wife's Lexus RX300 operators manual also says to use Premium fuel. We've been using Regular for about 94,000 miles now.
     
  4. Mar 22, 2007 at 10:00 AM
    #4
    tcBob

    tcBob Gringo Bandito Moderator

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    Someone at my dealership was saying you're better off using the cheaper stuff because it doesn't make any difference in the Tacoma.
     
  5. Mar 24, 2007 at 5:11 AM
    #5
    TacoMan

    TacoMan Active Member

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    My mom's maxima is supposed to have premium according to the owners manual as well. They ran 87 in it for over 80,000 miles. Then they had a problem with a computer component that affects the timing. They were told they had the problem because they ran a low octane fuel and the car had to compensate for it for too long a period, and that it would normally be okay to run 87 every now and then. It's just the car was designed to use premium. Anyway it was not a dealer and there was no warranty by that time, so my folks felt there was no reason the mechanic would have to shift blame. I plan on driving my truck for a long long time, so I run the premium as the book suggests.

    Compression usually has a deciding factor of what you should run, does anyone know what our compression is?
     
  6. Mar 24, 2007 at 2:05 PM
    #6
    tacomax

    tacomax Member

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    on the I4 is 9.6:1
    the 4.0L V6 is 10:1

    I utilized 91 and higher on my 05 prerunner from the beginning then tried 87 when prices were high and did noticed a slight pinging noise on hard acceleration or steep climbs..so I just stick with 91>

    High octane fuel has more potential energy but needs higher heat created by a higher compression engine to properly condition the fuel to release that higher potential energy

    from what i have read before on engines with compression ratios of 9.0 : 1 or less you can use unleaded 87 octane fuel. Engines with higher compression ratios usually require higher octane fuels.

    when fuel octane is too low for a given compression ratio, the fuel ignites prematurely, too early, and the fuel charge explodes instead of burning thus resulting in an incomplete combustion. so the engine tends to lose power and may cause engine damage. When you hear that knock or pinging, or even detonation, which may vary from a faint noise on light acceleration to a constant, deep hammering noise while driving at a constant speed. bad timing adjustments, vacuum leaks, or excessively lean fuel mixtures can too cause detonation...
     
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