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T-45 and 4.10, gear vs rpms?

Discussion in 'SN95 Cobras' started by paintballpyro1, Mar 29, 2013.

  1. paintballpyro1

    paintballpyro1 Active Member Established Member

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    I just swapped motors and switched from a auto to a t45 on my 96 gt. I have 4.10 gears already but going off of the rpm/gear calculator something seems off and being so new to manuals thought i could get some insight.

    when im driving down the road at 50mph in 5th im at about 3200 but according to the calculator i should be around 2700.

    1st gear 5-10mph im about at 2500-3000k
    3rd at 20mph im about at 2300-2500k

    To me it just seems like its revving more then it should be in gear. What could be wrong or should i look for?

    I may be off, just trying to pay attention more on my driving(still learning) then anything else.
     
  2. Mystic-SVT

    Mystic-SVT snuggle fest, mmmmm! Established Member

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    Did you install a speedcal when you swapped to the t45? I have 4.10s and at 70mph in 5th gear the engine is roughly at 2600-2700rpm.
     
  3. paintballpyro1

    paintballpyro1 Active Member Established Member

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    yea speedcal in(0010101010, what are you running?) i havent had mine on the freeway yet but i mean im already at 3k in 5th at 50mph
     
  4. DVJ38

    DVJ38 One mod at a time Established Member

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    Look through the how-to section and follow that thread and use all the calculators. Your settings have to be wrong.
     
  5. paintballpyro1

    paintballpyro1 Active Member Established Member

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    actually probably is, forgot i swapped my 96 auto ecu for a 96/97 manual ecu. I have the code off the new ecu but probably no way to figure what the original gear was. any ideas?

    checked the how to section, the links are all dead
     
    Last edited: Mar 29, 2013
  6. 4valved

    4valved Banned

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    There should be an axle code on your door sticker
     
  7. paintballpyro1

    paintballpyro1 Active Member Established Member

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    there was but ive swapped rear ends,trans and computers. thats also assuming the rear end ratio is programmed into the ecu
     
    Last edited: Mar 30, 2013
  8. SVT Rob

    SVT Rob Active Member Established Member

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    factory rear gears were 3.27's. This would have been what the "setting" was in the ECU. 3000rpm in 5th is pretty high even with 4.10's. Are you sure that you have a V8 tach and/or your tach is reading correctly?
     
  9. paintballpyro1

    paintballpyro1 Active Member Established Member

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    it was a v8 to v8 swap, i know my factory gear in the 96 was 3.08 and thats the setting i was using. i havent gotten to drive it yet with switching the dip switches for the 3.27/4.10 setting. i believe my tach is working correctly but who knows, its possible that my speedo was way off and why it was revving so much more.

    also with my next question, car was having starting issues. Found out autozone sold me 2 temp switches which was causing my car to lean way out. swapped for the correct sensors(hopefully), su284(temp sensor) and tu207(switch), now im getting po117, Engine Coolant Temperature (ECT) Circuit Low Input. im wondering if i got the sensors switched(if that would cause the current problem?) i havent been able to find any where for absoulte certain if pass side is the sensor and drivers is the switch or vise versa, hopefully someone knows.
     
  10. paintballpyro1

    paintballpyro1 Active Member Established Member

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    well switched the sensors around and drove, no check engine light but now i have a pending code p1151, Lack of HO2S-21 Switch, Sensor Indicates Lean. fml, 1 thing right after another, car drives fine but at idle it starts running rough.

    as far as switching the dip switches on the speedcal for the 3.27/4.10 setting. 3rd gear at 25mph, im right at 1700rpm so seems to be right now, just havent gotten it back on the highway to see where im at, at 50mph.
     

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