MPG

LamboTexas

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Finally did a hand calculated check of mpg for a 450 mile trip. 2021 AT4 6.2 stock other that Borla catback exhaust. Got 18.7 driving 80-85 on highway. Probably 80% hwy and 20% City driving. Pretty dang good for an engine with this horsepower. I’m going to be willing to give up a few mpg so that I can go with a bigger tire soon. Also, Truck bed had about 350 pounds of horse feed. Pretty happy.
 

I think the worse thing I've done for mpg wasn't the bigger tires.....it was the muffler delete....because it sounds so sweet that I'm mashing that pedal every chance I get now! Although our new Gov just passed a law in NY making aftermarket or loud exhaust illegal with a $1,000 fine. Not sure if that will be enforced or not out in the country where I live....but if it is then I'll be adding a muffler back
 

I'm consistently able to average 19-20 at highway speeds over any distance and 16-17 in the city. If I can put the cruise on in the 67-70 range I can squeeze 20+. My best average over 50 miles is 28.6. But that was coming down the mountain pass. :ROFLMAO:
 

I see you use regular gas, I purchased my 5.3 V8 and manual states 87 or higher recommend 91 which premium is closest. Any advise is welcomed. Thx.
The OEM recomends (not requires) premium on the 6.2L gas L87 engine. Lower octane will cause the computer to retard the timing (a little) which could result in a loss in MPG and hp. I ran 93 octane (premium here) until the first oil change, then I started using 87 and I haven't noticed a difference. However, I am careful not to use cheap gas or E85. If I had to tow something heavy, I probably would use premium. My 2¢
 

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