shifting RPMS and redline

Discussion in '40- & 55-Series Tech' started by slickrock, Nov 15, 2005.

  1. slickrock

    slickrock

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    Ok so I finally got my 73 FJ40 with the 3 speed tranny, F engine, and 4.11 gears with 33s running and it is totally different than my old CJ. With the rig being new to me and the new sounds and unfamiliar engine, what is a good shifting RPM so that I do not rev out the engine? the engine is a lot louder (less insulation and noiser gears) than I am familiar with. I also need to set the redline ont he tach. I know when to shift to not lug, but how high could my RPMS go before I start to redline? Until I can do it by sound, I do not want to be off-road and shift with too high RPMs. With the CJ, I was safe shifitng up to around 3000-3500 RPMS, but the engine in the cruiser is different. So what is considered normal shifting RPMS for the straight six for my 73.

    REdline is at 4000 but I do not what to get that high, but set my tach there.
     
  2. HawkDriver

    HawkDriver

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    One more time please not sure I understand what you're asking. ;p
     
  3. red66toy

    red66toy dorkus malorkus GOLD Star

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    i shift mine at around 2grand.
     
  4. CruisinGA

    CruisinGA

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    I don't have a tach.

    The lower you shift, the better your gas mileage.

    I've run my old F engine (what you have) for 3300 rpms for extended amounts of time.
     
  5. slickrock

    slickrock

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    Yeah I guess my wording is challenged. OK, in short, what is considered the optimal shifting RPM for an F Engine with the 3 speed tranny.



    Redline is about 4000 RPMS on this engine.

    Sorry about that.
     
  6. 2badfjs

    2badfjs

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    shifting in town 2k
    shifting to pass 2500-3k

    redline on a f motor is 4k
    but in reality, dont push it
    make redline 3500
     
  7. Mace

    Mace rock scientist.. Staff Member s-Moderator

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    Shift at 3-3500 ;)
     
  8. camcruiser13

    camcruiser13

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    i usually shift when i need to go a little faster.
     
  9. froggy

    froggy

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    I shift mine around 2200.....If i'm in town, I keep it in second gear (3 speed tranny) most of the time. I do a complete stop only if I see a cop.....
     
  10. 64fj40

    64fj40

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    i got a sbc and i shifted at around 2500-2800
     
  11. FJ40onNOS

    FJ40onNOS

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    i shift my 2f around 3800, but iv just let it go to 6000 just reving it DAM it was loud!
     
  12. red66toy

    red66toy dorkus malorkus GOLD Star

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    Yours is now getting rebuilt right?;)
     
  13. bad_religion_au

    bad_religion_au

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    i shift at 3700, peak power is at 3600 and it drops off dramatically from there so no point reving the rings out past that.

    as for downshifting, these are big healthy manly motors... i'll lug mine along at 600rpms in 4th if i'm lazy.

    and shifting early doesn't always = better gas milage, it all depends how your motor delivers it's power. if it struggles below 2500, and you shift at 2, it'll take alot longer to get to cruising speed, for example, with made up figures, 1 minute using 2 gallons of fuel an hour, or 5 minutes using 1.5 gallons of fuel an hour... which works out more efficient?

    probably best bet is to shift before your peak horsepower, so that the next gear falls back just below the torque peak, as the torque peak is where the motor is using ing the most energy from the fuel to propel the car.
     
  14. Horsehead

    Horsehead

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    I just wind out 1st and 2nd, skip third, stay in 4th... who needs a tach? just use your ear, I get too nervous to keep revving before that motor will actually give.
     
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