Highway Mileage Report For My '07 Nbs

steppetoe · May 22, 2007

For those who are interested; Last weekend I got the chance to test the highway mileage in a controlled manner. Had to make a highway drive of approximately 29 miles, and then a return trip on the same route. Used cruise the whole way, approximately 60 mph both directions. I did not measure the initial acceleration phase or the deceleration phase, and the fact that it is the same road going both ways should cancel out any freak numbers caused by long downhill/uphill runs, etc:

Cruise control at 60: trip one, averaged 21mpg, averaged 22mpg on the return trip, same speed. Later in the weekend had to make another there and back trip on a different route, slightly lower speed (around 57mph), also cruise control, averaged 21.5 overall. So there it is, with cruise and at 60ish, that's a pretty good performance I think. Remember, I did not measure initial acceleration up to speed or decelaration for my exit, so this is purely an average for a steady highway run.

Oh, the truck is stock with the exception of the removal of the lower front airdam and the addition of a soft tonneau cover.

dietz4ibanez · May 22, 2007

That aint bad!!!

Wingnut · May 23, 2007

My '02 Z71 would hit 21 mpg at 65 (ex cab, 5.3 motor)...I documented that twice using both the odometer and GPS as a backup on the distance portion of the equation on a couple of 300 mile plus trips. I think that removing that lower airdam might have killed a bit of the mileage for you...That's why it's there...To reduce undercarriage drag.

It's still impressive numbers though

tx1500nbs07 · May 23, 2007

I think that removing that lower airdam might have killed a bit of the mileage for you...That's why it's there...To reduce undercarriage drag.

It looks so much better without it though! I removed mine too - but saved it and all the screws in case I need to put it back on. It gives you back about 4 more " of front ground clearence that it was taking away. I tried to park my truck up a slight incline w/ tall grass at the lake a few days after I bought my truck and I almost ripped it off.

steppetoe · May 23, 2007

My '02 Z71 would hit 21 mpg at 65 (ex cab, 5.3 motor)...I documented that twice using both the odometer and GPS as a backup on the distance portion of the equation on a couple of 300 mile plus trips. I think that removing that lower airdam might have killed a bit of the mileage for you...That's why it's there...To reduce undercarriage drag.

It's still impressive numbers though

Yeah, I know removing the airdam cost me a little bit of mpg, but there was something not right about a 4x4 pickup that could barely clear a kerb so it had to go. I am pretty impressed with what I am getting now, although with only 1100 miles I hope that it improves a bit as the motor gets more broken in. I could never do better than 19.5 or so with my '03. Next time I have to take the same trip I want to see what difference adding that extra 5 mph makes. It already seems that it gets more or less the same mpg at 55 as it does at 60.

Wingnut · May 23, 2007

I think I'd actually set the cruise at around 63 or so. It had 3:73 gears in it...Tailgate up and A/C turned on.

I did a thread on it during one of the trips...I'll see if I can dig it up.

Wingnut · May 23, 2007

Found it! Click here.

sledr · May 23, 2007

It is good to hear things are improving.

My 04 SBEC Z71 w/ 5.3 and 3.73 is highway driven only and has 104,000 kms on it.

My commute to work is exactly 100 km one way so it is pretty easy to test fuel economy.

Every now and again I'll fill it (until it clicks and then round up to nearest dollar) and drive to work and back. When I get home I fill it up again. I am usually between 11.2 and 11.5 litres per 100 km which is 24.56 Imperial mpg or 20.45 US mpg.

My driving is an 90 km/h with cruise on the 2 lane road and 102 km/h with cruise on the 4 lane highway.

I am waiting a couple more years for the 6 speed auto to show up in the half tons before I trade my 04.

sledr

Z71Adrenaline · May 23, 2007

That doesn't sound bad. Why can't I get over 15 mpg with mine then?? I've got the 5.3L with 3.73 gears and 76,000 miles.. not fair!

redvett · May 23, 2007

The 6L80E will only improve fuel economy about 1/10th mpg approximately.

VMax2007 · May 23, 2007

For those who are interested; Last weekend I got the chance to test the highway mileage in a controlled manner. Had to make a highway drive of approximately 29 miles, and then a return trip on the same route. Used cruise the whole way, approximately 60 mph both directions. I did not measure the initial acceleration phase or the deceleration phase, and the fact that it is the same road going both ways should cancel out any freak numbers caused by long downhill/uphill runs, etc:

Cruise control at 60: trip one, averaged 21mpg, averaged 22mpg on the return trip, same speed. Later in the weekend had to make another there and back trip on a different route, slightly lower speed (around 57mph), also cruise control, averaged 21.5 overall. So there it is, with cruise and at 60ish, that's a pretty good performance I think. Remember, I did not measure initial acceleration up to speed or decelaration for my exit, so this is purely an average for a steady highway run.

Oh, the truck is stock with the exception of the removal of the lower front airdam and the addition of a soft tonneau cover.

How did you do this test? With the DIC? Does the DIC have a resettable mpg trip average? I thought it only has instant and an overall? Or did you reset the overall one? I want to be able to keep the overall one set to check long-term mileage, but am wondering if it has a resettable trip one too. I keep forgetting to look into this.

steppetoe · May 23, 2007

For those who are interested; Last weekend I got the chance to test the highway mileage in a controlled manner. Had to make a highway drive of approximately 29 miles, and then a return trip on the same route. Used cruise the whole way, approximately 60 mph both directions. I did not measure the initial acceleration phase or the deceleration phase, and the fact that it is the same road going both ways should cancel out any freak numbers caused by long downhill/uphill runs, etc:

Cruise control at 60: trip one, averaged 21mpg, averaged 22mpg on the return trip, same speed. Later in the weekend had to make another there and back trip on a different route, slightly lower speed (around 57mph), also cruise control, averaged 21.5 overall. So there it is, with cruise and at 60ish, that's a pretty good performance I think. Remember, I did not measure initial acceleration up to speed or decelaration for my exit, so this is purely an average for a steady highway run.

Oh, the truck is stock with the exception of the removal of the lower front airdam and the addition of a soft tonneau cover.

How did you do this test? With the DIC? Does the DIC have a resettable mpg trip average? I thought it only has instant and an overall? Or did you reset the overall one? I want to be able to keep the overall one set to check long-term mileage, but am wondering if it has a resettable trip one too. I keep forgetting to look into this.

Yes, I reset the average. I trust the numbers because I have previously checked them against a calculated average and found them to be spot-on. I am not aware of there being a resettable trip mpg where you can maintain a separate average.

VMax2007 · May 23, 2007

For those who are interested; Last weekend I got the chance to test the highway mileage in a controlled manner. Had to make a highway drive of approximately 29 miles, and then a return trip on the same route. Used cruise the whole way, approximately 60 mph both directions. I did not measure the initial acceleration phase or the deceleration phase, and the fact that it is the same road going both ways should cancel out any freak numbers caused by long downhill/uphill runs, etc:

Cruise control at 60: trip one, averaged 21mpg, averaged 22mpg on the return trip, same speed. Later in the weekend had to make another there and back trip on a different route, slightly lower speed (around 57mph), also cruise control, averaged 21.5 overall. So there it is, with cruise and at 60ish, that's a pretty good performance I think. Remember, I did not measure initial acceleration up to speed or decelaration for my exit, so this is purely an average for a steady highway run.

Oh, the truck is stock with the exception of the removal of the lower front airdam and the addition of a soft tonneau cover.

How did you do this test? With the DIC? Does the DIC have a resettable mpg trip average? I thought it only has instant and an overall? Or did you reset the overall one? I want to be able to keep the overall one set to check long-term mileage, but am wondering if it has a resettable trip one too. I keep forgetting to look into this.

Yes, I reset the average. I trust the numbers because I have previously checked them against a calculated average and found them to be spot-on. I am not aware of there being a resettable trip mpg where you can maintain a separate average.

There is no doubt in my mind that the DIC is dead nuts on. I was hoping I could take spot check (trip) averages while not losing the overall avg. Oh well. Thanks for the info.

steppetoe · May 23, 2007

For those who are interested; Last weekend I got the chance to test the highway mileage in a controlled manner. Had to make a highway drive of approximately 29 miles, and then a return trip on the same route. Used cruise the whole way, approximately 60 mph both directions. I did not measure the initial acceleration phase or the deceleration phase, and the fact that it is the same road going both ways should cancel out any freak numbers caused by long downhill/uphill runs, etc:

Cruise control at 60: trip one, averaged 21mpg, averaged 22mpg on the return trip, same speed. Later in the weekend had to make another there and back trip on a different route, slightly lower speed (around 57mph), also cruise control, averaged 21.5 overall. So there it is, with cruise and at 60ish, that's a pretty good performance I think. Remember, I did not measure initial acceleration up to speed or decelaration for my exit, so this is purely an average for a steady highway run.

Oh, the truck is stock with the exception of the removal of the lower front airdam and the addition of a soft tonneau cover.

How did you do this test? With the DIC? Does the DIC have a resettable mpg trip average? I thought it only has instant and an overall? Or did you reset the overall one? I want to be able to keep the overall one set to check long-term mileage, but am wondering if it has a resettable trip one too. I keep forgetting to look into this.

Yes, I reset the average. I trust the numbers because I have previously checked them against a calculated average and found them to be spot-on. I am not aware of there being a resettable trip mpg where you can maintain a separate average.

There is no doubt in my mind that the DIC is dead nuts on. I was hoping I could take spot check (trip) averages while not losing the overall avg. Oh well. Thanks for the info.

Just a thought, but isn't there a dic function telling you total gallons of fuel used? As long as this doesn't reset along with resetting average mpg, won't that give you what you want, obviously by just dividing miles by gallons?

topdj · May 24, 2007

There is no doubt in my mind that the DIC is dead nuts on. I was hoping I could take spot check (trip) averages while not losing the overall avg. Oh well. Thanks for the info.

Just a thought, but isn't there a dic function telling you total gallons of fuel used? As long as this doesn't reset along with resetting average mpg, won't that give you what you want, obviously by just dividing miles by gallons?

I been doing that, it works well if you dont want to reset your average mpg