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Is 4.56 too much?

This is a discussion on Is 4.56 too much? within the Drivetrain forums, part of the LSx Technical Help Section category; Originally Posted by maxwax If you plan on running it in the 1/4 mile a 4:56 is defiantly out. Huh??? ...

  1. #21
    Moderator Firebirdjones's Avatar
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    Quote Originally Posted by maxwax View Post
    If you plan on running it in the 1/4 mile a 4:56 is defiantly out.
    Huh??? If the car is equipped with even just a camshaft that requires 6500 rpm shift points the 4.56's would be a beautiful setup.
    Easily livable on the street in my opinion as well.

    I do agree though however the 4L60E is not the best trans for dragstrip action. Not that it's weak, but the gear spread sucks. A 3.06 first gear is horrible and not necessary. In order to get enough rear gear in the car for best dragstrip performance it makes first gear rediculous and looking for second before the car moves 20 feet. Then the rpm drop is horrendous. It's fun on the street but not the best trans for dragstrip action.
    A 400 or 350 turbo would be better suited.

  2. #22
    LSX whore allbaugh_04's Avatar
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    Yea i am sure those trans' are great for the strip. However, my stall really helps me out with the shift extension.

    My goal is now to have the fastest ls1 with 2.73s

  3. #23
    Blown, Stroked, & Sprayed

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    I am pretty sure with 4.56's you will shift into OD at the end of the 1/4

  4. #24
    Moderator Firebirdjones's Avatar
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    Quote Originally Posted by Ed Blown Vert View Post
    I am pretty sure with 4.56's you will shift into OD at the end of the 1/4
    The only reason that would happen is if you have surpassed your shift points,,,since 3rd is 1:1 and for example you have a motor shifting at 6500-6700 or so,,,that 4th gear shift shouldn't happen unless you are running some wheenie 24 inch tall tires or something

  5. #25
    Moderator Firebirdjones's Avatar
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    Here I did some math for you. This is based on some of my own experience with a few of my cars that run a real gear.

    With a 4.56 gear,,and running a typical 28 inch tall tire and a motor that can spin to 6500 rpm in the traps you can cross at 119 mph with 1:1 trans gear.

    You could stretch that to 6700 rpm and still hit 122 mph with no overdrive.

    Now if you want to run a small 26 inch tall tire which is how all 4th gens are equipped, you can hit 113 mph at 6500 rpm or stretch that to 116 mph at 6700 rpms,,,,thats a pretty typical mph for a strong bolt on LS1 motor that shouldn't have any problem spinning that kind of rpm. This is also providing you have enough HP to push the car in question to that kind of mph.

    I ran 4.56's all the time at the strip and on the street with a high strung gen 1 small block in a Nova, and now currently in my nomad,,,and honestly could even use a little more gear since I cross the traps in the 6400 rpm range.

  6. #26
    Blown, Stroked, & Sprayed

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    All I remember is crossing the line @ 121 with my 3.23's

  7. #27
    Moderator Firebirdjones's Avatar
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    Quote Originally Posted by Ed Blown Vert View Post
    All I remember is crossing the line @ 121 with my 3.23's
    Sorry, I'm talking about NA motors. Since you are running a blower with nitrous on top of that it changes everything.

    Typically you don't want alot of gear when running a power adder like that since the low end grunt is in spades.

    I'm talking about a typical high strung small block that wants to spin and lacks bottom end.

  8. #28
    Blown, Stroked, & Sprayed

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    Sounds like we are on the same page.

  9. #29
    LSX whore allbaugh_04's Avatar
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    So what is my threshold with 2.73s..whats my max mph???

    LOL

  10. #30
    Moderator Firebirdjones's Avatar
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    Quote Originally Posted by allbaugh_04 View Post
    So what is my threshold with 2.73s..whats my max mph???

    LOL
    Depends on the HP you make. It would really take alot of grunt to maximize that gear.

  11. #31
    Junior Member driftpin's Avatar
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    If you had the engine, 200 mph. Going through the traps, around 150ish. It would take a whole lot of engine.

  12. #32
    Moderator Firebirdjones's Avatar
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    To give you an idea,,,top fuel generally runs a 3.00 gear or so and hit 300+ mph in the traps. Thats with 4-6,000 HP though in a relatively light car

    In all honesty though if you really want to make the most of that 2.73 gear I would drop in the new 454 cubed LSx motor and then throw a 200 shot on top of it.

    You can still find 2.73 gears for a 12 bolt,,,,lol.
    Last edited by Firebirdjones; 03-05-2009 at 09:19 AM.

  13. #33
    LSX whore allbaugh_04's Avatar
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    If the rear ever breaks i will see if i can go with 3.42s in a 12-bolt.

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