Fuel Economy Tanked

[Padraig]

Ouch!!! Glad I kept mine stock. At 80 I can still get 25/27 mpg.

Padraig

 

[olyelr]

Did you recalibrate the speedo when you put larger tires on?

If not, your mpg will show less, as well as speed will show slower than actual.

 

[CTown Duramax]

I am surprised at this. I have been doing a 96 mile round trip on I-95 once every other week for four years and always get 30-31 going 75+mph. If I look at my 50 mile average early in the trip, it's much lower, like 22mpg, but by the time I get home, it's 30+ mpg.

 

[Jayhawkeye3]

As mentioned above, apparently my 24 inch vossens, 35 inch nittos and level kid kill the mileage.

That said, it still is random sometimes.

Last week I had a 350 mile round trip the same afternoon/evening. Identical conditions. One way I got 16.5 mpg, the other way 20.1.

 

[swathdiver]

As mentioned above, apparently my 24 inch vossens, 35 inch nittos and level kid kill the mileage.

That said, it still is random sometimes.

Last week I had a 350 mile round trip the same afternoon/evening. Identical conditions. One way I got 16.5 mpg, the other way 20.1.

Headwinds, rain, road grade, etc. can all contribute to these one way differences.

 

[olyelr]

As mentioned above, apparently my 24 inch vossens, 35 inch nittos and level kid kill the mileage.

That said, it still is random sometimes.

Last week I had a 350 mile round trip the same afternoon/evening. Identical conditions. One way I got 16.5 mpg, the other way 20.1.

Headwinds, rain, road grade, etc. can all contribute to these one way differences.

Yes, especially the headwinds. Thats a killer. And often times the reverse trip is the complete apposite (tailwind instead of headwind and vice versa). Makes a BIG difference.

But yes, heavier wheels/tires that are bigger with less rolling resistance should have a noticeable difference in mpg, negatively. The higher/raised vehicle does not help either.

 

[Stbentoak]

With a lot of things being said. I will say that my LZ0 seems to get worse mileage in general than the LM2 I had before it. All in the same basic conditions. I still have no complaints with it. But it seems like my generic daily mileage is more in the low 20s. My LM2 was never below about 23 miles per gallon and on the highway, it would crack 30 regularly. My best highway mileage on the LZ0 is 29.3.

 

[CTown Duramax]

With a lot of things being said. I will say that my LZ0 seems to get worse mileage in general than the LM2 I had before it. All in the same basic conditions. I still have no complaints with it. But it seems like my generic daily mileage is more in the low 20s. My LM2 was never below about 23 miles per gallon and on the highway, it would crack 30 regularly. My best highway mileage on the LZ0 is 29.3.

The GM stats for the LZ0 claim a higher output than the LM2, 305hp/495lbft vs 277hp/460lbft. Do you notice the difference?

 

[Stbentoak]

The GM stats for the LZ0 claim a higher output than the LM2, 305hp/495lbft vs 277hp/460lbft. Do you notice the difference?

Oh, I can possibly notice some difference. It's not huge though. I personally feel there is more of a loss of miles per gallon versus gain of power really. But unfortunately, I don't get it out on the highway enough to really reap the benefits or catch the hwy readings of long distance (100 mile+) Drives.

 

[CTown Duramax]

I think with all the traffic here in Eastern Mass, I might be better off with the LM2's 460lb/ft at 1500 rpm than a gain in higher end output.

 

[Scarey]

I’ve been in California for a couple months and it appears my fuel mileage has decreased. Researched CAs biodiesel and apparently biodiesel is less energy dense, 10%. That seems about the same ratio decrease in mpg I’m getting. Upside is, biodiesel has better lubricity, fuel pump lubtication.

 

[Stbentoak]

Going to take a 750 mile romp in a few weeks. We'll see what she does on that trip.....

 

[Jim376]

We drove our Tahoe 1200 miles cross country when it was new and had about 500 miles on it. Averaged 32 mpg at generally a bit over the posted limits ;-)

Jim

 

[Stbentoak]

Going to take a 750 mile romp in a few weeks. We'll see what she does on that trip.....

Well, I can report after this trip. My faith has been restored. We did about 700 miles over the weekend. Its overall average was about 27.5. On the 80 mile an hour stretches, we did about 26 to 27 miles per gallon. But we had 150 miles stretch that we couldn't go over 55. On those stretches, it returned about 33-34 miles per gallon.
So I guess the big take away is it really needs to get out on the road for some good stretches to get the mileage that I remember. But it's still in there and still attainable. Glad to see it as I was a little bit depressed about how it was working around town. It just reaffirms the fact that this vehicle is a great road vehicle......

 

[JayceeP]

Well, I can report after this trip. My faith has been restored. We did about 700 miles over the weekend. Its overall average was about 27.5. On the 80 mile an hour stretches, we did about 26 to 27 miles per gallon. But we had 150 miles stretch that we couldn't go over 55. On those stretches, it returned about 33-34 miles per gallon.
So I guess the big take away is it really needs to get out on the road for some good stretches to get the mileage that I remember. But it's still in there and still attainable. Glad to see it as I was a little bit depressed about how it was working around town. It just reaffirms the fact that this vehicle is a great road vehicle......

Wild! Good stuff.

 

[BlackHC2025]

'25 HC with 24" factory wheels, LZ0, 9,300 miles now with about 2/3rds highway, no towing, lots of luggage, cargo from cleaning out deceased parents house; lots of highway from that. 24 MPG per the vehicle computer OA. I'm completely satisfied with the mileage, especially in comparison to a Durango Hellcat .

 

[Jayhawkeye3]

I’m at 5,600 miles and 17.8 MPG. The level kit and 24” wheels with nitto terras really do put a hurt on the mileage.

I do get 20-21 driving around suburbia at 45mph.