What's with the mileage?

[Alan Applegate]

My 2024 Eco-Boost Premium, non PP, was delivered with 283 miles on it, as it was driven from a dealer in Los Cruses, to my dealer here in Roswell. The dash showed 29.6 mpg, but some of that was due to idling while waiting until the highway reopened near White Sands (missile launch).

Since the delivery on September 4, 2024, the car has not left Roswell, proper until yesterday afternoon. A neighbor got stranded in Lovington, NM a 191 mile round trip, and I went to get him. I filled the tank before I left, and again when I got back. Of the 191 miles driven (indicated), about 15 were sort of in town miles, but no stop lights. Average highway speed was ≈69 mph.

During the trip, the mileage rate according to the dash peaked at 39.7 mpg. It is important to note the EPA rating for this specific vehicle is 22 city, 33 highway. This would indicate something was amiss. However, when I refueled the fuel load was a mere 5 gallons even after slightly topping off the tank. This calculates to 38.2 mpg. Incidentally, my average in town mileage is ≈18.6 mpg.

Since this isn’t a PP vehicle, the differential ratio is 3.15, not the 3.55 like the PP vehicles. The engine rpm was ≈1,750 at 70 mph (indicated). I did use the cruise control.

I don’t know what others get, but the numbers seem a bit strange to me.

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[highvoltage]

I get better hwy than advertised on my GT.

 

[kagemusha2662]

If you’re not pressing that pedal as much and just cruising, these cars are surprisingly capable of pretty good mileage. Not really surprised that you could hit that if you’re just on the highway most of the time. Cruise control also calculates for mileage/efficiency while maintaining speed, so that also helps.

 

[Sofa King]

What's so strange about that... I have found with most cars; I struggle to get even close to advertised "city MPG" but often surpass the "hwy MPG" on long trips. Mostly city in my S650 Eco (HPP, so 3.55's) gets about the same as you... the lifetime is about 22.5mpg. Mostly highway and open country roads in the wife's S550 Eco (base w/FP tune, 3.15's) and it's always 30+ mpg, and the lifetime is well above 30 as well. Of course my right foot is much "bigger" than hers, so that can account for some loss of MPG... YMMV, lol.

 

[Neggytive]

not winding it up into the twilight zone and three OD gears will do that.

My GT Premium averaged 30 MPG on the trip from NH to Florida

Around town with the occasional exhibition of speed I still get 22 MPG

Not bad for a 3900 pound car

 

[S650sunshine]

I only get about 14.1 mpg city in my GT PP

 

[SSuperDave]

22 city and 35 hwy, cruise at 78 mph on my GT with 3.15's.

 

[ListedGuru]

22 city and 35 hwy, cruise at 78 mph on my GT with 3.15's.

So your seeing 35 mpg highway on a 24 GT with 3.15's? I have a 24 GT with 3.55's and the highest I've seen highway is 25 and usually around 24 or so depending on my speed (10 speed AT). I guess gearing must make a huge difference?

 

[SSuperDave]

I drove from Houston to Austin and back, what's on the highway reset the mileage indicator and did get 35 both ways running between 75 and 80 mph I was amazed.

 

[Ryunker]

My 2024 Eco-Boost Premium, non PP, was delivered with 283 miles on it, as it was driven from a dealer in Los Cruses, to my dealer here in Roswell. The dash showed 29.6 mpg, but some of that was due to idling while waiting until the highway reopened near White Sands (missile launch).

Since the delivery on September 4, 2024, the car has not left Roswell, proper until yesterday afternoon. A neighbor got stranded in Lovington, NM a 191 mile round trip, and I went to get him. I filled the tank before I left, and again when I got back. Of the 191 miles driven (indicated), about 15 were sort of in town miles, but no stop lights. Average highway speed was ≈69 mph.

During the trip, the mileage rate according to the dash peaked at 39.7 mpg. It is important to note the EPA rating for this specific vehicle is 22 city, 33 highway. This would indicate something was amiss. However, when I refueled the fuel load was a mere 5 gallons even after slightly topping off the tank. This calculates to 38.2 mpg. Incidentally, my average in town mileage is ≈18.6 mpg.

Since this isn’t a PP vehicle, the differential ratio is 3.15, not the 3.55 like the PP vehicles. The engine rpm was ≈1,750 at 70 mph (indicated). I did use the cruise control.

I don’t know what others get, but the numbers seem a bit strange to me.

Wind is a huge factor.

In our DH premium with the tremec on a road trip we top 25mpg all day long, yet got stuck with a $1,300 gas guzzler fee.

 

[highvoltage]

22 city and 35 hwy, cruise at 78 mph on my GT with 3.15's.

Yea hand calculate that. No way you getting those numbers on a GT

 

[SSuperDave]

Accelerate to speed, set the cruise, zero the mileage and that's what I got I didn't hand calculate anything. I left with a full tank showing range of 300 miles when I shut it off and got more gas and filled up it showed range of 390.
What's the saying? Your mileage may vary

 

[Wiley Marmot]

I get better hwy than advertised on my GT.

I've seen in excess of 28 MPG on extended highway trips @ 60 MPH with the cruise engaged. That's virtually the same mileage I used to get with my 200 HP v6 2004 Pontiac Grand Prix GT!

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