Which gear ratio will do me best in the long run

Discussion in 'Drivetrain' started by PinkieT, Jul 27, 2016.

  1. PinkieT

    PinkieT Well-Known Member

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    98 GT, manual trans, 3.27 rear. I bought a set of Cobra brakes and snagged the 3.73 geared rear axle with it. Engine mods right now are BBK CAI, performance coils and wires, Flowmaster muffs. Phase I of the build will add PI heads and intake, larger throttle body and plenum. However, Phase II will be a mild turbo or blower setup. Should I keep the 3.27s in there knowing the power adder is in the future, or just go with the 3.73 rear?
     
  2. Frank.JD.Perez

    Frank.JD.Perez Well-Known Member

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    depends, what do you want to use your car for
     
  3. the5.ohh

    the5.ohh Legend

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    Unless you're running stupid high boost and racing it 24/7, I'd go 3.55 and call it a day.
     
  4. Rob04Mach1

    Rob04Mach1 New Member

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    I've had Stangs with 4.1 & 3.7 Gears but I was running tall over height Street Slicks so it was a good combo
    For the normal (short tires) most Stangs run (and I run on my Mach 1) I have to admit the 3.5 Gear is perfect for big power :headbang:
     
  5. 1998cobrasvt

    1998cobrasvt Well-Known Member

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    3.55 or 3.73 for sure.
     
  6. 07GtS197

    07GtS197 Well-Known Member

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    Since you plan on boosting your stang I wouldnt do the pi head swap. It raises your compression so the amount of boost you can on pump gas is limited.
     
  7. PinkieT

    PinkieT Well-Known Member

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    Thanks for the input. I already have two axles, one with 3.21 in the car and the Cobra axle with 3.73 sitting in the garage, so swapping gears to 3.55 is not something I really want to do.
     
  8. PinkieT

    PinkieT Well-Known Member

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    Fun street cruiser that won't get spanked too badly by newer cars.
     
  9. PinkieT

    PinkieT Well-Known Member

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    Thanks for the input. I already have two axles, one with 3.27 in the car and the Cobra axle with 3.73 sitting in the garage, so swapping gears to 3.55 is not something I really want to do. Boost would be low, racing not on the radar.
     
  10. Frank.JD.Perez

    Frank.JD.Perez Well-Known Member

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    I'm going with 355s after I swap out the 410s in my car but I'm also tracking the car. But I still use it for a daily so having 373s in 2 previous sn95s I'd vouche for them. They're fun and not too aggressive. Especially if you have different rear ends and they're already in then just go to the 373s, you'll enjoy them
     
  11. Frank.JD.Perez

    Frank.JD.Perez Well-Known Member

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    Also...you're gonna get spanked....learn to live with it. I don't ever try to worry if I'm gonna get spanked or not because I know my car doesnt compete. I do however know for the year and generation of cars put out in that Era that it's one of the faster cars so I hold my car up to others from the 1990-2000 time because that's roughly what it could "compete" with
     
  12. PinkieT

    PinkieT Well-Known Member

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    Good point. I read though that the power added to a motor by a blower or turbo is based on the power of the engine you start with, so a power adder PI motor with 260 hp stock would have more power at the end than a NPI motor starting with 225 hp. Maybe I should just do the PI swap, headers, throttle body and plenum, and a tune and call it a 300 hp day.
     
  13. the5.ohh

    the5.ohh Legend

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    Hmmmmmm fair enough. Go 3.73!
     
  14. PinkieT

    PinkieT Well-Known Member

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    My 500 hp 440 six pack did a lot of spanking. I'm at the age that now I just wanna have a fun drive. I was actually thinking of a Miata - great handling fun cars - but I had to go with a rumbling V8.
     
  15. Frank.JD.Perez

    Frank.JD.Perez Well-Known Member

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    lol well a 500hp isnt a stock or era correct number for our cars hahah, with that much power by all means my friend do all the walking over fire kittens and vetties you want
     
  16. Witzy0070

    Witzy0070 Active Member

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    After running multiple power adders and 3.55s, 3.73s, and 4.30s in less than a 4 year span... On your build I would personally recommend the 3.73s. I miss my 3.73s because of the way the T-45 has ratios in 3rd. However, you're running a T-5 from what I gather. The 3.73s will be happy with future mods and current and give you a beyond good balance for drivability, acceleration, and highway comfort in fuel economy and noise.
     
  17. g36 monkey

    g36 monkey Moderator Staff SN95 Supporter

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    Absolutely the 3.73. Sounds like the ideal gear for your plans.
     
  18. 07GtS197

    07GtS197 Well-Known Member

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    Yes and no. Im not saying to skip the blower because using to stock npi heads will limit you. They wont flow like pi's but you can still make good power with npi heads and will keep the stock compression ratio. Doing a pi swap minus the heads wont give you gains like that of a full pi swap but youre not losing out on much.

    My recommendation, 3.73's, turbo, npi heads, pi intake, either pi or blower cams and an aftermarket throttle body and plenum. A pi swap and full bolt ons would give you a good bump in power but what if you want more? The compression will necessitate either lower boost or race gas/e85.
     
  19. Thomas_W

    Thomas_W Well-Known Member

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    Speaking from a having an all motor car on 4.10's (both NPI, PI head swapped and Pi'd motor) roots blower with 4.10's and a turbo PI'd motor with 3:55's...

    either go 3.55 or 3.27. 3.55's even with a fully built motor on 12psi (about 550rwhp) was stupidly fun and would knock the tires off in every gear (including fifth!).
    With a turbo you benefit more with a numerically lower gear like a 3.27 or 3.55 because the engine stays loaded longer so get the turbo to spool and stay within its power band longer. To Tall of a gear and your constantly shifting, to low and you never get to shift, so its really a balancing act.

    If it was me, i'd stick with the 3.27's.
     
  20. rz5.0

    rz5.0 Legend

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    Turbo 3.27, centri blower, 3.73.. Don't worry about the high compression.. It will be more fun with a high compression low boost set up

    Sent from my LGLS991 using Tapatalk