TFLtrucks just proved what we already knew about mpg and the 2.7L

DieselDrax · 2025-10-03T13:03:38-0400

hyperv6 said:
My mpg in town on secondary roads worth stop and go is 21. The highway has been 26 mpg.

The wife’s 21 Acadia 3.6 gets 22-23 around town and highway it gets 31-32 depending on the speed. Gearing makes a big difference.

If you have a limited slip you get the 3:42 gear and it cuts into mpg.

Also the Acadia is AWD but if in 2WD it is fwd. less drivetrain drag and the rear system disengages the drive shaft.

Hmmm...the Acadia V6 has a 3.49:1 axle ratio and the 2.5L has a 3.80:1 ratio. The active differential in the rear of the AT4 doesn't change the ratio.

commonme said:
@hyperv6 Uhm. All else being equal, the 3:42 should get better mileage and reduced low end torque than the 3:55 or 3:72.

You're referring to the truck ratios, they're talking about the Acadia.

Not to nit pick, but ratios are N:1. 3.42:1, 3.73:1. Not 3:42 or 3:73. Those as ratios wouldn't function in a vehicle.

w1kedz · 2025-10-03T13:52:35-0400

TeamKingsley said:
I hope you all are not going by the dash display to tell you MPG. You must calculate gallons put in at the pump and miles driven over a period to be certain. The dash only estimates the MPG for you. . . .

The MPG from the dash display is not an "estimate". It's a calculation based on actual fuel usage from the injectors along with odometer. It is relatively accurate, possibly more accurate than using a pump calculation where you may or may not fill the tank to the exact level each time. To make pump calculations accurate you would have to use the exact same physical pump and it must not over/under fill on the cutoff, this is highly unlikely. The only thing that would make the dash calculation widly innacurrate would be if you change your tire size.

The only "estimate" in relation to MPG is your miles remaining on the tank.

w1kedz · 2025-10-03T14:05:19-0400

Driving a turbo engine for gas mileage efficiency requires very thoughtful driving.

In most cases people driving an NA engine will have a much smoother gas mileage usage for a tank for varying terrain and circumstances. In an NA engine if you go from point A to point B and it's 100 miles you will likely have very similar gas mileage as if you were to go from the same point A to point B over 100 miles again. A turbo's gas mileage will be very volatile depending on the terrain and circumstances. If you go from point A to point B over 100 miles, you may have significantly different mileage if your repeat the same trip.

I average 24-27 on a 450 mile trip up to northern cali, I also average 17-18 on the same trip depending on the day and how attentive I am to conservation. I average 18-20 in town in socal, I also average 10-13 around the same town depending on the day and how attentive I am.

I don't think anyone buys a colorado for gas mileage, its a utility vehicle, but if you did buy for mileage then to get the most out of it you'll want to spend some time learning techniques to stay out of boost as much as possible, as soon as you're in boost you're guzzling.

I don't trust the test in the video, I don't trust that they drove the trucks with the best conservation in mind. If they just use cruise control, or don't actively try to save gas then NA is easier to get a favorable MPG rating. If they were super mindful then the 4 cyl turbo should have gotten better than 20mpg as I've easily bested that on several trips.

hyperv6 · 2025-10-03T20:42:52-0400

commonme said:
@hyperv6 Uhm. All else being equal, the 3:42 should get better mileage and reduced low end torque than the 3:55 or 3:72.

Yes but the Acadia I was speaking of got better MPG as it had less gear.

Many trucks with open diffs for years were 3:08 and even in the 2:90’s.

The Acadia has less driveline drag. With pretty much the same engine with 2 more HP. It get the added MPG due to this as the weight is similar too.

It is what it is. It gets much better highway,

hyperv6 · 2025-10-03T20:45:31-0400

DieselDrax said:
Hmmm...the Acadia V6 has a 3.49:1 axle ratio and the 2.5L has a 3.80:1 ratio. The active differential in the rear of the AT4 doesn't change the ratio.

You're referring to the truck ratios, they're talking about the Acadia.

Not to nit pick, but ratios are N:1. 3.42:1, 3.73:1. Not 3:42 or 3:73. Those as ratios wouldn't function in a vehicle.

I thought it to be less. Either way the Acadia does get better MPG.

DieselDrax · 2025-10-03T20:48:26-0400

hyperv6 said:
Gear is different in the Denali as is the power vectoring. The AT4 was more aggressive,

I can find zero documentation showing that and zero GM part numbers for differentials showing anything other than the 2 ratios I listed that depend on engine. Not saying you're wrong, just that I can find nothing to back it up.

hyperv6 · 2025-10-03T20:55:58-0400

w1kedz said:
Driving a turbo engine for gas mileage efficiency requires very thoughtful driving.

In most cases people driving an NA engine will have a much smoother gas mileage usage for a tank for varying terrain and circumstances. In an NA engine if you go from point A to point B and it's 100 miles you will likely have very similar gas mileage as if you were to go from the same point A to point B over 100 miles again. A turbo's gas mileage will be very volatile depending on the terrain and circumstances. If you go from point A to point B over 100 miles, you may have significantly different mileage if your repeat the same trip.

I average 24-27 on a 450 mile trip up to northern cali, I also average 17-18 on the same trip depending on the day and how attentive I am to conservation. I average 18-20 in town in socal, I also average 10-13 around the same town depending on the day and how attentive I am.

I don't think anyone buys a colorado for gas mileage, its a utility vehicle, but if you did buy for mileage then to get the most out of it you'll want to spend some time learning techniques to stay out of boost as much as possible, as soon as you're in boost you're guzzling.

I don't trust the test in the video, I don't trust that they drove the trucks with the best conservation in mind. If they just use cruise control, or don't actively try to save gas then NA is easier to get a favorable MPG rating. If they were super mindful then the 4 cyl turbo should have gotten better than 20mpg as I've easily bested that on several trips.

Saving gas with a turbo is not hard, You just don’t step on it hard. Pretty much the same thing as any other engine. Also on most engines Today just getting off the throttle cuts the fuel.

My old Turbo could get 2 more mopg in town if you drove normal. If you hammered the on ramps it Wild drop 1-2 mpg,

It was nothing dramatic like in the past, Direct injection has really changed Turbo engines with better measured fuel and the cooling of fuel in the cylinder lets the companies add more boost and compression.

CaryBosse · 2025-10-03T21:24:20-0400

w1kedz said:
...

I don't think anyone buys a colorado for gas mileage, its a utility vehicle, but if you did buy for mileage then to get the most out of it you'll want to spend some time learning techniques to stay out of boost as much as possible, as soon as you're in boost you're guzzling.

....

The only way I end up in a Colorado would be to see a good mileage improvement over my Silverado or totaling the Silverado and needing a replacement truck. So, mileage is important.

With similar MPGs, I can't justify replacing my Silverado to make parking easier.

I do agree that i don't trust these tests. I typically beat EPA MPG estimates, both in my old Canyon and my Silerado. My best 25 miles in my 2nd gen Canyon was over 34 MPG. I. My Silverado, I have a best of over 28 MPG for 50 miles. The Canyon mileage was an attempt by me to set a high mark but I have no idea on the Silverado.

Mr Stig · 2025-10-03T21:30:30-0400

Im all about smiles per gallon, not miles per gallon.
Plus im self employed and fuel is a write off.
Turbo noises are amazing too.

littleblazer · 2025-10-04T04:46:27-0400

With a turbo I've always found being a little more aggressive than with an NA engine yields better mpgs. NA light acceleration to the speed limit will typically yield the best mpg as you are shifting your position on the VE curve map with throttle opening. With the turbo the whole point is to use the boost to get on the best area of the VE curve so if you lightly accelerate outside of boost you're actually utilizing your power in a less efficient manner.

I've had both variations of the equinox (NA and boosted) and thats what it took on both to get the best economy. Now I'm not talking flooring it but a little further to generate some boost which resulted in short acceleration times. The turbo car was significantly more efficient though the 1.5 turbo was less powerful than the outgoing 2.4. The 1.5 made a little more torque. Both are dogs and I actually blew apart the charge pipe day one of owning the 1.5... apparently that was a known issue with the quick connect style fitting they used to attach it to the throttle body.

YoshiV819 · 2025-10-04T06:18:58-0400

As others have said, the turbo noise is great. And, if there was a V8 stuffed in my Canyon it would probably become much more difficult to replace something that's broke. I'm not a against V8's, have had plenty but its absence in my truck means nothing to me. Actually, the savings outweigh the possibly slightly lower fuel economy because I didn't HAVE to get an aftermarket exhaust to accentuate a V8!

commonme · 2025-10-04T13:50:12-0400

@littleblazer This sounds like it somewhat goes along with what a car magazine (R&T or Car & Driver, I don't recall which) found 25+ years ago with the BMW e and i series. The e (efficient) said to actually step on it harder to get to speed quicker to get better mileage. The i said to baby it. That was the only difference they found.
On digging, they found the additional frictional loss from higher RPMs was less than the loss from the throttled engine for acceleration, along with you spend less time/distance in lower gears.

American Truck · 2025-10-05T00:18:56-0400

mcmsdavis60 said:
The f150 has a great 10 speeds

Yes…that was codeveloped with GM.

TFLtrucks just proved what we already knew about mpg and the 2.7L

DieselDrax

w1kedz

w1kedz

hyperv6

hyperv6

DieselDrax

hyperv6

CaryBosse

Mr Stig

littleblazer

YoshiV819

commonme

American Truck

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