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Thread: Diff. swap 3.23MPG? vs 3.46 MPG?

  1. #1
    Join Date
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    Diff. swap 3.23MPG? vs 3.46 MPG?

    The poeple who had/has swapped there diff. did you guys see any decrease of MPG, if so how much?

    Do you guys use the car as DD?
    98 ///M3 Sedan Club Member #165

    Suspension: | H&R Sports | UUC SwayBarbarian | UUC RTAB | UUC Rear Adjustable Control Arms | UUC HD-RSM | Motorsport X-brace | AC Schnitzer Front Strut Brace | Sachs Sport Shocks
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  2. #2
    Join Date
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    Lexington, SC
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    11 550 Sport Pkg, 08 X5
    Quote Originally Posted by BinhM3 View Post
    The poeple who had/has swapped there diff. did you guys see any decrease of MPG, if so how much?

    Do you guys use the car as DD?
    I really didnt notice much after my diff swap... Not enough to warrant not switching to a 3.46... BTW this is my DD and i drive roughly 400 miles a week...
    98 E36 M3 Sedan (Sold)
    08 E60 550 M Sport Package (Sold)
    12 F10 535 M Sport Package (Sold)
    11 F10 550 M Sport Package (Current)
    08 E70 X3 3.0si (Current)
    97 E36 M3 (Track Car in progress)

  3. #3
    Join Date
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    Well here is a thought for you. When I went from a 3.23 to a 3.73, I realized that to get the same or better MPG, all I had to do was match the rpm from normal driving with the 3.23 to the normal driving rpm with my 3.73 (although its all highway driving for me). For instance, I used to cruise at 80mph and would be at about 3.5k rpms. Now I cruise at about 72mph to keep the same rpms while also getting the same MPG. Brilliant eh?

    Also for city driving, I have actually found myself to be shifting up to 5th gear very quickly since I have short gears and plenty of power so it really doesn't hinder my MPG.

    In my opinion, I don't think you will notice that big of a difference with that small of a change in gearing.


  4. #4
    Join Date
    Feb 2001
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    Connecticut
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    IP S52 E30
    I barely noticed an increase when I went from stock to a 3.46

    It wasn't until the jump from 3.46 to 3.64 that I saw my gas consumption double without amending my driving habits.
    Chris

  5. #5
    Join Date
    Feb 2006
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    Tim @ BMW of Dallas
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    98 Z3 2.8
    I recently swapped from a 3.15 to a 3.46 and noticed no difference.. between 280 and 320 miles to a tank depending on how i drive..
    96 320i Touring
    98 Z3 2.8 Roadster
    01 PY M Coupe
    96 Z3 1.9 - DASC
    95 318ti Clubsport
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    13 smart fortwo



  6. #6
    Join Date
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    M3-T,G63,S63,Huracan-Evo
    I haven't noticed a difference with my MPG. I think it would have to do more with where you let your engine stay at rpm wise more than what gears you have.

  7. #7
    Join Date
    Dec 2007
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    thx for the info guys. Im planning to buy a 3.46 in the near future.
    98 ///M3 Sedan Club Member #165

    Suspension: | H&R Sports | UUC SwayBarbarian | UUC RTAB | UUC Rear Adjustable Control Arms | UUC HD-RSM | Motorsport X-brace | AC Schnitzer Front Strut Brace | Sachs Sport Shocks
    Performance: | M50 Manifold | AFE Short Ram | RS Lip Spoiler | Beyern Mesh 18x8.5 18x9.5 | CDV Delete | UUC UDP |
    Cosmetic: | ZKW Elipsoids | Predator Chromium Angel Eyes | Prolumen HID LB 6k | Apexcone HID Fogs 5k | ZHP Shift Knob |
    Next Upgrade: |UUC FCAB | Erics Vanos | UUC Stage 2 Clutch Kit | UUC SSK | TMS Shorty Headers | HFM 540 | AA Gen3 exhaust | AA Software | or save up and go SC

  8. #8
    Join Date
    Mar 2001
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    Buy mine binh. It's fs
    '99 Estoril Blue + Dove Grey ///M3 coupe
    '04 Jet Black + Cinnamon ///
    M3 coupe


  9. #9
    Join Date
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    Quote Originally Posted by Vitolo View Post
    Buy mine binh. It's fs

    your car or your LSD? well its pointless for me to ask you how much the LSD is going for since i dont have much cash atm...
    98 ///M3 Sedan Club Member #165

    Suspension: | H&R Sports | UUC SwayBarbarian | UUC RTAB | UUC Rear Adjustable Control Arms | UUC HD-RSM | Motorsport X-brace | AC Schnitzer Front Strut Brace | Sachs Sport Shocks
    Performance: | M50 Manifold | AFE Short Ram | RS Lip Spoiler | Beyern Mesh 18x8.5 18x9.5 | CDV Delete | UUC UDP |
    Cosmetic: | ZKW Elipsoids | Predator Chromium Angel Eyes | Prolumen HID LB 6k | Apexcone HID Fogs 5k | ZHP Shift Knob |
    Next Upgrade: |UUC FCAB | Erics Vanos | UUC Stage 2 Clutch Kit | UUC SSK | TMS Shorty Headers | HFM 540 | AA Gen3 exhaust | AA Software | or save up and go SC

  10. #10
    Join Date
    Mar 2001
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    FL
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    E36, E46
    LSD. Worth a shot!
    '99 Estoril Blue + Dove Grey ///M3 coupe
    '04 Jet Black + Cinnamon ///
    M3 coupe


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