Mpg on 2.7t and mods

Jason_ · May 20, 2020

Lifetime average for me is 22.3. Hand calc and not the computer. Mainly highway driving without much traffic with COVID.

http://www.fuelly.com/car/chevrolet/silverado_1500/2020/jason14227/984531

I expect that to go down as traffic starts to pick back up the next few months.

Sunnyd360 · May 20, 2020

got to love forums! I think its okay that everyone is contributing their MPG its nice to hear we are all averaging descent MPG! Also we all noticed with all of this COVID stuff some have increased MPG some have gone down like myself since I work from home and my driving is to the local grocery store!

Sunnyd360 · May 20, 2020

1 hour ago, Jason_ said:

Lifetime average for me is 22.3. Hand calc and not the computer. Mainly highway driving without much traffic with COVID.

http://www.fuelly.com/car/chevrolet/silverado_1500/2020/jason14227/984531

I expect that to go down as traffic starts to pick back up the next few months.

thats awesome! I am really enjoying this light traffic I hope this is the new norm here I am in the Portland, Oregon area so our traffic has always been so bad!

Colossus · May 20, 2020

15 hours ago, Jonofmac said:

No fuel additives will stop carbon build up on valves. You have to use a cleaner that you spray into the intake.

Sent from my SM-N960U using Tapatalk

Of course not. But it will help keep things cleaner and running smoother and easier to treat.

HondaHawkGT · May 21, 2020

On 5/20/2020 at 12:17 AM, CamGTP said:

Link to that review?

I didn't gain MPG when I specifically tuned my truck to run on 89+ octane over 87 octane ( for power reasons). The change in octane rating is just changing how resistant it is to ping/knock. If the stoich ratio of the fuel is the same for 87 and 93 octane, what would make the mileage change? The computer doesn't even know what octane you put in the tank, it doesn't even know if you put E0 or E10 in the tank because the stoich value is set to one single number as there is no alcohol sensor. The fuel trims would auto adjust for any minor difference anyway which wouldn't change the mileage.

I've spent many days behind a laptop tuning vehicles and for me it hasn't worked like that for mileage gains/losses by using different fuels not including E85. To lose 10-15% is a ton just because of 87 or 89 octane and that doesn't make much sense.

The truck doesn't need an octane sensor because the engine doesn't care what the octane is since practically all modern engines are tuned to bounce off the knock sensors regardless of what the manufacturer recommends. The AFR isn't going to be different, but the amount of ignition timing possible before there's knock will be different depending on the fuel the engine is running on. The more timing, the more of the combustion energy to be converted into energy to move the vehicle. A factory tuned L83 5.3 is known for having a bit of KR on 87, which is going to cause the engine to run a little less timing and run a little less efficient. From what I've read, companies like GM and Honda have been pushing for higher minimum octane gasoline standards for this very reason, as that's one of the few ways manufacturers can continue to keep up with CAFE fuel economy standards.

Also, in most of the US 91+ octane fuel isn't an ethanol blend. Since alcohol has slightly less energy content compared to gasoline, the engine has to burn slightly more fuel for the same amount of power output.

Lots of little differences in fuel efficiency that add up when it comes to the calculated fuel economy over long distances. The GM Powertrain engineers make their money coming up with factory tunes that maximizes fuel economy, so I wouldn't expect much to be left on the table.

Colossus · May 22, 2020

9 hours ago, HondaHawkGT said:

Also, in most of the US 91+ octane fuel isn't an ethanol blend.

Incorrect on that part. They have been putting Ethanol in regular, mid, and premium grades of fuel for many years now, For much of the USA. There are *some* stations (not entire brand lines, just separate stations) that might be able to offer Ethanol free fuel, but not all. I've seen people say that Shell premium or Chevron premium doesn't contain ethanol. It does around here. At most of the stations, and the same with most major cities and areas where there are emissions standards in place.

Your best bet is to go to www.pure-gas.org

HondaHawkGT · May 22, 2020

47 minutes ago, Colossus said:

Incorrect on that part. They have been putting Ethanol in regular, mid, and premium grades of fuel for many years now, For much of the USA. There are *some* stations (not entire brand lines, just separate stations) that might be able to offer Ethanol free fuel, but not all. I've seen people say that Shell premium or Chevron premium doesn't contain ethanol. It does around here. At most of the stations, and the same with most major cities and areas where there are emissions standards in place.

Your best bet is to go to www.pure-gas.org

In my state as well as neighboring states all 91+ is ethanol free. Even more so after a few dozen refineries in the US were given exemption from having to add ethanol at all. Maybe dense urban areas mainly have stations with 91+ ethanol blends, but its extremely uncommon in the states I've traveled to.