MPG Computer Not Accurate?

[GT Pony]

do 3.73 gears all that dramatically decrease fuel economy? I commute 100 miles/day so even a drop of 2-3mpg compared to 3.31 or 3.55 would really make me reconsider buying the PP.

Per my calculations, if you were in 6th gear doing 72 MPH with 3.31 gears the engine would be turning ~2000 RPM. With 3.73 gears, the engine would be turning ~2250 RPM, so that's only a 250 RPM increase. I doubt you would lose much MPG at all ... probably 1 or less.

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[Stangnut]

do 3.73 gears all that dramatically decrease fuel economy? I commute 100 miles/day so even a drop of 2-3mpg compared to 3.31 or 3.55 would really make me reconsider buying the PP.

Yes. I checked S197 threads before the S550 came out and they had the same results as the S550's are showing now. 1-2 mpg from 3.31 to 3.55 and another 1-2 mpg from 3.55 to 3.73. Check the mpg thread on here and with a few exeexceptions you'll see the same thing. If 2-4 mpg isn't much to you then go for it.

 

[Qwkynuf]

Why even worry about miles per gallon. Gas is cheap enjoy, drive your Mustang and turn off the miles per gallon read out.

I am averaging about 2000 miles per month, and that could go even go up. I don't obsess about my gas mileage, but when I leave my house for work tomorrow, I might luck out and be home for dinner - or I might be spending the night 6 hours away.

I can't think of a single reason to waste money unnecessarily, and it's not unusual for me to buy 2-3 tanks of gas per week.

"Cheap gas" is kind of relative.

 

[GPhilly04]

I am using one called Gas Manager

https://itunes.apple.com/us/app/gas-manager-fuel-consumption/id448662326?mt=8

Thanks a ton!

 

[krahooligan]

That doesn't sound right at all. I can pull 25 freeway no problem at 70 mph. City I struggle to get 14 though.

in city I use 1st to 3rd to 5th and im averaging about 16-16.5 mpg. I don't commute on the freeway ever. :(

 

[Old 5 Oh]

do 3.73 gears all that dramatically decrease fuel economy? I commute 100 miles/day so even a drop of 2-3mpg compared to 3.31 or 3.55 would really make me reconsider buying the PP.

Yes, the gears make a difference. As noted, my well-broken-in 3.15s will now get me really close to 30 mpg on the freeway (65-70 mph). That's up from about 26-27 when the car was new. The PPs are just not seeing that mileage and are commonly 23-24 in the same conditions. Now, as you can also see, most guys don't care and that's good. None of us bought GTs to optimize our fuel economy. But for those who drive a lot and do care, careful options selection will make a measurable difference in your wallet over the course of time.

 

[JimmyTwoTimes]

My trip computer has been optimistic by 1.5 mpg overall in my 3,000 miles of driving, but on particular tanks it can be as much as 3-4 mpg optimistic. It varies. It tends to do a worse job of estimating mpg the lower your mpg is -- so, on tanks where I've manually calculated 9 or 10 mpg, it'll say 13-14 mpg on the display. On tanks where I've calculated 17 or 18 mpg (really rare; I've only had one tank over 18 mpg so far in 3,000 miles) it'll be closer. I don't really worry about it too much.

 

[mfelix15GT]

I have a PP gt and just about a week ago I was averaging 25.4 going 70mph. I was going the limit most of the time and wasn't heavy on the foot. My trip was about 50 miles in when I had to get off the freeway but I'm hoping or assuming that in a longer trip my MPG reading would of stayed at around 25-27. When I got off the interstate I went on a highway and I was going 60 for about 20-25 miles and my MPG went up to about 26.7.

 

[Old 5 Oh]

My trip computer has been optimistic by 1.5 mpg overall in my 3,000 miles of driving, but on particular tanks it can be as much as 3-4 mpg optimistic. It varies. It tends to do a worse job of estimating mpg the lower your mpg is.

Interesting. (All of this is just curiosity really. Not important.) Mine seems to be linear. The higher the mpg for the tank, the farther off the computer will be. About 1.5 at 24 mpg, which is my most common mileage for my mix of open road and suburban driving.

 

[Spartan]

It seems the 3.55's in the auto's are getting good MPG also. Like many of said, they think the 3.55 for the auto tranny are ideal.

 

[Old 5 Oh]

It seems the 3.55's in the auto's are getting good MPG also. Like many of said, they think the 3.55 for the auto tranny are ideal.

They do seem to get good reviews. "Ideal" may be in the eye of the beholder. For me, I can't imagine why I would want the car to have a higher pulse than it has with the 3.15s. It's SO powerful that it doesn't need 12.7% additional rpm going on all the time. IMO.

 

[Spartan]

They do seem to get good reviews. "Ideal" may be in the eye of the beholder. For me, I can't imagine why I would want the car to have a higher pulse than it has with the 3.15s. It's SO powerful that it doesn't need 12.7% additional rpm going on all the time. IMO.

Yah for the majority of us, do we need the 3.55s...highly doubtful, especially in the GT.

But then again, hearing the people in the auto in the V6 with 3.15s and then those that got the 3.55s, they said it was a night and day difference.

 

[JimmyTwoTimes]

Yah for the majority of us, do we need the 3.55s...highly doubtful, especially in the GT.

But then again, hearing the people in the auto in the V6 with 3.15s and then those that got the 3.55s, they said it was a night and day difference.

Also remember that the 2011-2014 autos had 2.73's standard.

 

[Spartan]

Also remember that the 2011-2014 autos had 2.73's standard.

Im talking about a few on there that have driven the 3.15's in the V6 and then also tested the 3.55's with the auto tranny in both and they said that the 3.55's bar none were way to go with the auto/V6...so I would assume that would somewhat apply to the GT also (then again the GT has torque all the way for night and day)

 

[mj]

My readout was consistently running around .7 mpgs high for the first 5,000 miles or so, but since than it has been rather reliable -- it never reads more than .3 over actual, and will even read too low sometimes.

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