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Soo happy!! 3.90's are on!

Discussion in 'Driveline' started by combatstang, Dec 21, 2004.

  1. Bob Cosby

    Bob Cosby Active Member Established Member

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    LOL. The shape of the powerbands (in the useable rpm range) are nearly identical - just that the blown motor is significantly higher. I could have geared the car to go 2-3 mph faster, but would have likely lost at least a tenth in ET.

    The gearing philosophy for getting best MPH is different than that for getting the best ET.

    1-2 tenths is VERY worth it for me. I'd much rather run a 10.9 than an 11.0. Might not be worth it for someone else.

    $400-$500 for 1-2 tenths is a VERY reasonable gain. No, its not near as good as bolting on a pulley and going half a second faster, but it is still a very reasonable $$$ amount to spend for the gains. And you WILL feel it on the street.

    Beyond that....Uncle. Ya'll decide for yourselves...my 3.90s and live axle go in late next week. That's nowhere near optimum, but it will provide a nice increase in performance, ET, feel, etc over the stock 3.55s. :)
     
  2. BL1SN8K

    BL1SN8K New Member Established Member

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    For those of you with 3.90's, is there much change in driving response in part-throttle, off-boost conditions? I have a porky convertible that doesn't feel particularly eager in those situations and I was considering a gear change to liven that up. Any thoughts?
     
  3. fastball19

    fastball19 South Florida King ! Established Member

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    :banana:

    :banana:
     
  4. SWEET03COBRA

    SWEET03COBRA damn this wheel hop! Established Member

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    See, this is what I'm think too, my vert could use the extra UMTH when I get on it. Anyone shed some like on the gear change in a vert vs. a coupe?
     
  5. 11secCobra

    11secCobra Way2Fast4These LS1 guys Established Member

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    verts are a little bit heavier than a coupe, but i doubt itll make any difference. in the city, youll get better gas mileage because the motor doesent have to work as hard to get up to speed. your motor is most efficient at its torque peak, so the closer you are to your torque peak, the better gas mileage youll get. (im not saying cruising around at 3800 is gonna save you gas, but that little bit of extra RPM while cruising may help ya out)
     
    Last edited: Jan 12, 2005
  6. SWEET03COBRA

    SWEET03COBRA damn this wheel hop! Established Member

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    So if the two were to get gears, verts would be more likely to benefit?
     
  7. projekZERO

    projekZERO Werd Established Member

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    i have a vert.

    gears will help nomotter what.

    the problem with our verts isnt just the weight itself but where the weight is.

    alot fo the weight is in the doors and front a/pillars, this is not ideal for weight transfer and traction.

    also our springs are softer, and again doesnt help us with traction.

    our frames flexing also contributes to lesser traction, and im not sure but might change the pinion angle slightly when going down the track which will rob some power.

    good subframes, suspension mods, and reducing the weight over the front end goes along way on verts to keep up with the coupes.

    but yes the gears will help.
     
  8. SWEET03COBRA

    SWEET03COBRA damn this wheel hop! Established Member

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    cool, thanks
     
  9. redstaf426

    redstaf426 New Member Established Member

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    You know what I'm hearing :rollseyes

    Excuses

    Excuses

    and more Excuses

    J/K Buddy :thumbsup:

    Let us know how you and Marc do on Sunday :beer:
     
  10. projekZERO

    projekZERO Werd Established Member

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    sonicvenum (juan)

    drove marcs car to a [email protected] 118.9 mph tonight and lacr ricky

    1.73 60 ft and [email protected] mph in the eight. and thats at our slow track.

    not to bad
     
  11. redstaf426

    redstaf426 New Member Established Member

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    Dame,from 12.3-11.7??same tires??

    3.90s for me :pepper: :pepper: :pepper:
     
  12. projekZERO

    projekZERO Werd Established Member

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    no e.t. streets

    but that 60ft is nothing you couldnt pull

    your cars have about the same power ricky

    that run was atleast a 7.3 @ 94mph at any other track
     
    Last edited: Jan 15, 2005
  13. projekZERO

    projekZERO Werd Established Member

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    the point is the gears are not holding back his e.t or mph whatsoever. 119 mph is very fast for lacr
     
  14. redstaf426

    redstaf426 New Member Established Member

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    Sweet,will get gears after clutch.
     
  15. projekZERO

    projekZERO Werd Established Member

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  16. JB

    JB beautiful loser Established Member

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    unarchived

    :read:
     
  17. Power Trip

    Power Trip New Member Established Member

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    Ok i dunno how old this thread is as i was searching some gear related threads. But damn all this argueing is crazy. If anyone honestly thinks that steeper gears wont make your car faster, you are nuts!!

    Bob cosby - alot of GREAT tech info.. Good to have you on these boards.
     
  18. adamb258

    adamb258 New Member Established Member

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    i was todl with 4.10's the rpm at 70 in 6th gear is about 2,300 rpms. Is that acurate? I looked for a gear calc but couldnt find one and figures one of you guys would know
     
  19. Snarf

    Snarf Lacey Chabert FTW! Established Member

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    Thats pretty spot-on. 75 in 6th with my 4.10s is almost exaclty 2500.
     
  20. adamb258

    adamb258 New Member Established Member

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    i thin kif i do it im jsut gonna go 4.10's had them in my mach and loved them
     

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