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RPM's???

Discussion in 'The Garage' started by huntaholic123, Sep 19, 2004.

  1. huntaholic123

    huntaholic123 Newbie

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    RPM\'s???

    I was wondering if anyone knew what a 1985 K5 Blazer with a 305 small block red lines at?????? Some input would be great. Thanks
     
  2. Hossbaby50

    Hossbaby50 3/4 ton status

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    Re: RPM\'s???

    probably 5000-5500. It won't have any power up there though so it is a waste of time reving it that high.
     
  3. pauly383

    pauly383 Daddy383 Staff Member Moderator

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    Re: RPM\'s???

    I believe 4500 rpm is too much for these motors . Thats why they were geared from the factory to shift at 3500 and cruise below 2000 rpm on the freeway /forums/images/graemlins/k5.gif /forums/images/graemlins/k5.gif
     
  4. 84_Chevy_K10

    84_Chevy_K10 Banned

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    Re: RPM\'s???

    4500 is the factory horsepower peak and I've never seen a truck that shifted below that.

    Airplane gears in the '80s were designed to try to save gas. GM finally realized it didn't work later on and they no longer gear trucks that way. Nothing significant has changed mechancially with the engines, they just realized a lugging engine gets horrible fuel mileage.
     
  5. pauly383

    pauly383 Daddy383 Staff Member Moderator

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    Re: RPM\'s???

    Mine will shift way before that , even if I am on it hard . It was that way when I had stock size tires , it is that way with the 33's , and it will probably be that way when I regear to compensate for the 33's . Why wouldn't " They " gear it to work in the torque peak instead of the horsepower peak /forums/images/graemlins/dunno.gif
     
  6. 84_Chevy_K10

    84_Chevy_K10 Banned

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    Re: RPM\'s???

    They do gear it to cruise at the torque peak for economy, but shift at, or above the horsepower peak on hard acceleration for maxiumum performance.

    Torque gets a load moving, but horsepower = speed.
     
  7. beater_k20

    beater_k20 Banned

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    Re: RPM\'s???

    [ QUOTE ]
    Torque gets a load moving, but horsepower = mantain speed.

    [/ QUOTE ]

    fixed it for ya. /forums/images/graemlins/screwy.gif
     
  8. m j

    m j 1/2 ton status

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    Re: RPM\'s???

    they are one and the same thing
    one is with a time factor one is without a time factor
    to argue like they are unrelated is idiotic magasine banter
     
  9. SUBFAN

    SUBFAN 1/2 ton status

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    Re: RPM\'s???

    [ QUOTE ]
    They do gear it to cruise at the torque peak for economy, but shift at, or above the horsepower peak on hard acceleration for maxiumum performance.

    [/ QUOTE ]

    BS....Show me a gas motor that makes it's peak torque at 1800 - 2000 rpm's. THEY DO NOT GEAR VEHICLES WITH GAS MOTORS TO OPERATE AT THEIR TORQUE PEAK, PERIOD.

    Dang near all SBC's have a torque peak around 3000 - 3500, and the general public would not put up with screaming motors so the manufacturers DO NOT make them that way.... /forums/images/graemlins/screwy.gif
     
  10. ntsqd

    ntsqd 1/2 ton status

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    Re: RPM\'s???

    [ QUOTE ]
    they are one and the same thing
    one is with a time factor one is without a time factor
    to argue like they are unrelated is idiotic magasine banter

    [/ QUOTE ]

    Hum, a mis-statement and then a semi-correct contradiction of that statement.

    Torque is a measurement of the engine's ability to do work, i.e. how much work it can do.
    HP is the rate that it can do the work at.

    F1 & Indy car engines can't do much work (very low torque), but they can do it very fast (high RPM HP).
    OTR diesels can do a huge amount of work (lots of torque), but they can't do it very fast (comparatively).

    The 80's era saw the OE's trying to use as little RPM as possible as a way to meet CAFE. They built engines with lots of low end and no RPM potential. The 305 came from all of this. Small bore with a long stroke is by nature a low reving torque engine. I recall an 80's Z-28 that was factory redlined at about 4200 and quit pulling well b4 that. Short shifting it and 'leaning it over' made it go way faster than trying to rev the snot out of it.
     
  11. 84_Chevy_K10

    84_Chevy_K10 Banned

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    Re: RPM\'s???

    [ QUOTE ]
    [ QUOTE ]
    They do gear it to cruise at the torque peak for economy, but shift at, or above the horsepower peak on hard acceleration for maxiumum performance.

    [/ QUOTE ]

    BS....Show me a gas motor that makes it's peak torque at 1800 - 2000 rpm's. THEY DO NOT GEAR VEHICLES WITH GAS MOTORS TO OPERATE AT THEIR TORQUE PEAK, PERIOD.

    Dang near all SBC's have a torque peak around 3000 - 3500, and the general public would not put up with screaming motors so the manufacturers DO NOT make them that way.... /forums/images/graemlins/screwy.gif

    [/ QUOTE ]

    Tell that to my '87 C30 that is geared for 3,000 RPM @ 65 from the factory.

    Generally speaking most newer vehicles cruise much higher than the old ones. My truck was geared for about 1,600 RPM @ 65 from the factory which is pathetic.

    At the torque peak the engine is most efficient. Most engines are geared at or just below this for optimum fuel economy.
     
  12. NoSmog73

    NoSmog73 1/2 ton status

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    Re: RPM\'s???

    [ QUOTE ]
    4500 is the factory horsepower peak and I've never seen a truck that shifted below that.

    [/ QUOTE ]

    /forums/images/graemlins/histerical.gif /forums/images/graemlins/histerical.gif /forums/images/graemlins/histerical.gif

    You have to be kidding me tim /forums/images/graemlins/shame.gif...You are saying that trucks are not shifting anytime before 4500 from the factory....
    I wouldnt want to ride in a truck that shifted that high..I'd end up with whiplash and be sueing GM. or deaf from the noise. /forums/images/graemlins/shame.gif
     
  13. gokartergo

    gokartergo 3/4 ton status Staff Member Moderator

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    Re: RPM\'s???

    [ QUOTE ]
    [ QUOTE ]
    [ QUOTE ]
    They do gear it to cruise at the torque peak for economy, but shift at, or above the horsepower peak on hard acceleration for maxiumum performance.

    [/ QUOTE ]

    BS....Show me a gas motor that makes it's peak torque at 1800 - 2000 rpm's. THEY DO NOT GEAR VEHICLES WITH GAS MOTORS TO OPERATE AT THEIR TORQUE PEAK, PERIOD.

    Dang near all SBC's have a torque peak around 3000 - 3500, and the general public would not put up with screaming motors so the manufacturers DO NOT make them that way.... /forums/images/graemlins/screwy.gif

    [/ QUOTE ]

    Tell that to my '87 C30 that is geared for 3,000 RPM @ 65 from the factory.

    Generally speaking most newer vehicles cruise much higher than the old ones. My truck was geared for about 1,600 RPM @ 65 from the factory which is pathetic.

    At the torque peak the engine is most efficient. Most engines are geared at or just below this for optimum fuel economy.

    [/ QUOTE ]

    What gears did your truck come with.. asssuming 3.73 with a 4 speed and 29 inch tires is 2809. If they where 3.08'3 then it would be 2320 rpms.. .. Even if you had 2.73's you would be at 2056 rpm's... Wrong again Timmy
     
  14. 84_Chevy_K10

    84_Chevy_K10 Banned

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    Re: RPM\'s???

    [ QUOTE ]
    [ QUOTE ]
    [ QUOTE ]
    [ QUOTE ]
    They do gear it to cruise at the torque peak for economy, but shift at, or above the horsepower peak on hard acceleration for maxiumum performance.

    [/ QUOTE ]

    BS....Show me a gas motor that makes it's peak torque at 1800 - 2000 rpm's. THEY DO NOT GEAR VEHICLES WITH GAS MOTORS TO OPERATE AT THEIR TORQUE PEAK, PERIOD.

    Dang near all SBC's have a torque peak around 3000 - 3500, and the general public would not put up with screaming motors so the manufacturers DO NOT make them that way.... /forums/images/graemlins/screwy.gif

    [/ QUOTE ]

    Tell that to my '87 C30 that is geared for 3,000 RPM @ 65 from the factory.

    Generally speaking most newer vehicles cruise much higher than the old ones. My truck was geared for about 1,600 RPM @ 65 from the factory which is pathetic.

    At the torque peak the engine is most efficient. Most engines are geared at or just below this for optimum fuel economy.

    [/ QUOTE ]

    What gears did your truck come with.. asssuming 3.73 with a 4 speed and 29 inch tires is 2809. If they where 3.08'3 then it would be 2320 rpms.. .. Even if you had 2.73's you would be at 2056 rpm's... Wrong again Timmy

    [/ QUOTE ]

    My truck came from the factory with a 700R4 and 2.73s. I converted it to a 4 speed. At least you got the 29" tires right.

    Open mouth, insert foot. Why don't you shove the rest of your leg inside while you're at it?

    1439.2 @ 65. I guess I was being a little optimistic.

    Check it out for yourself, 29" tires, 2.73 gears, .7:1 overdrive.
     
  15. gokartergo

    gokartergo 3/4 ton status Staff Member Moderator

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    Re: RPM\'s???

    You always bragged about a 4 speed.. I am tired of fighting with you.. I am not the only one.. All you are doing is fighting with everybody..Look at how many arguments you have going right now.. If I ever get the pleasure of meeting you.I will take my foot out of my mouth and stick it up your arse.. /forums/images/graemlins/ignore.gif
     
  16. 84_Chevy_K10

    84_Chevy_K10 Banned

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    Re: RPM\'s???

    I'm not even going to answer to that. Nice try.
     
  17. gokartergo

    gokartergo 3/4 ton status Staff Member Moderator

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    Re: RPM\'s???

    [ QUOTE ]
    I'm not even going to answer to that. Nice try.

    [/ QUOTE ]

    Why not??????????????
     
  18. 84_Chevy_K10

    84_Chevy_K10 Banned

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    Re: RPM\'s???

    Because if I continued I'd only be flaming you. There is no tech to be had from me saying anything additional in this post unless a question is raised.

    If you want to flame me, send me a PM.
     
  19. gokartergo

    gokartergo 3/4 ton status Staff Member Moderator

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    Re: RPM\'s???

    Will do and then you will be the first and probably the only person I will ever put on ignore........ /forums/images/graemlins/yikes.gif
     
  20. 87BrnRsd

    87BrnRsd 1/2 ton status

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    Re: RPM\'s???

    [ QUOTE ]
    There is no tech to be had from me saying anything additional in this post unless a question is raised.

    [/ QUOTE ]
    Couldnt have said it better myself. I dont see what the problem with these forums is anymore. It seems that people are more concerned with arguing than answering the initial question. We all drive fullsizes. I could see an argument maybe if one of us was a heeper. /forums/images/graemlins/ignore.gif
    And to answer the initial question- I would say somewhere near 5000. But pushing one of these motors that high is just plain stupid.
    -Harrison
     

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