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Just got 26 MPG on my road trip...how much will 3.73s hurt?

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Old Sep 17, 2010 | 07:30 PM
  #1  
Jason E's Avatar
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Just got 26 MPG on my road trip...how much will 3.73s hurt?

So, with my M5/3.08 geared LO3 I just got 25.5 MPG for my 275 mile road trip from MA to ME this week. I'm leaving tomorrow, and expect to get about the same MPG on the way home. This is 90% highway, doing between 70-80 MPH.

I have a 3.73 posi rear from an '83 L69 sitting in my garage I was going to swap into it over the winter. After this great display of MPG though, I wonder...with all else being equal, how much will my MPG decrease? 2-3 MPG on a trip like this? 1-2 MPG around town?
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Old Sep 17, 2010 | 07:58 PM
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Re: Just got 26 MPG on my road trip...how much will 3.73s hurt?

Yeah, I'd guess you would lose 2-3 mpg. My old '92 that was auto and 2.73's would get 27-28 mpg under the same conditions.
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Old Sep 19, 2010 | 02:27 AM
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Re: Just got 26 MPG on my road trip...how much will 3.73s hurt?

I say you lose at least 5 mpg.
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