Gas mileage...3.73s

merc123

Active Member
Jan 27, 2003
420
2
39
North GA
I tried to find some of my old posts but can't. I don't remember getting 21 MPG with 3.73's before I got a new tranny and rear end. Now it averages 20 to 21 with the 10% ethanol blend if that matters. This sound about right because I thought I was getting 23 before I parked it for a while..
 
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I tried to find some of my old posts but can't. I don't remember getting 21 MPG with 3.73's before I got a new tranny and rear end. Now it averages 20 to 21 with the 10% ethanol blend if that matters. This sound about right because I thought I was getting 23 before I parked it for a while..

With my 3650 I got 22 on a full tank with having fun of it for some. I think highway driving should get 23-24 pretty easily. I filled my tank up halfway today and checked milage and got 18 but that was with my foot in it for a good portion of it. Just got the gears saturday so thats why I don't have a huge test range. As stated its all about your right foot but also if the car is tuned and everything is running properly.
 
ethanol has less energy per unit of volume compared to gasoline so getting a little bit lower gas mileage is reasonable.

That being said there are some advantages to ethanol. The advantage of ethanol unfortunately are negligible at 10%, the only thing it does is raise corn prices and give you worse gas mileage. Theoretically w/ higher mixes of ethanol you can have higher octane and run more aggressive tunes, more power, etc etc.
 
When my parents picked up their new truck which isn't a flex fuel vhecile they were told that if they do run more ethanol than a small % such as 10 or so that eventually it would ruin the fuel lines and break them down.. Not so sure about all of that but they said the fuel lines were different for flex fuel stuff.
 
Just figured it out on the way in this morning... the new rear end from FRPP was supposed to have 3.73 gears in it... It actually has 4.10s. I'm running 2500 @ 70 MPH. I thought it was a bit high because when I had 3.73's I was running around 2200 or less. That would explain why 1st gear goes so quick now.