MPG on 22 LTD vs 21's

[Byrds8]

Anyone know why the 22 LTD 5.3L's are rated for less MPG than the 21's? Its the same engine and transmission along with the same HP/TQ. It makes no sense.

[reeseb]

You must have been looking at 2022 trucks without DFM. 

[newdude]

Yep, the ratings changed because of DFM unavailability.  They had to re-cert them with the EPA.

[Byrds8]

I thought that may have been the case, but when I look them up, the 5.3L with DFM is still rated lower. According to the window sticker etc, the Silverado I traded the problem child Sierra in for, has DFM and has the lower ratings. Mine is rated 15/20 with a 17 combined. If it didnt have DFM I would understand that rating since that was what the Sierra was rated for. However, thats not the case.

[TxTruckMan]

It's the same engine, but DFM is disabled.  DFM doesn't affect HP/TQ at all.

 

There's also Auto Start/Stop to consider.

[Byrds8]

Sadly it has AS/S also. I plan on getting the Pulsar LT to take care of both items. Still though, wonder why the ratings are different. Riding down the interstate shows less MPG than the Sierra at the same speeds also. Granted the Sierra had a Air Raid MIT and no muffler but it shouldnt be that huge of a difference. The Sierra had no DFM and would get 20mpg running the highway (at 70) with no issue.

Edited March 21, 2022 by Byrds8

[Wiggums]

Maybe because they used bigger mud terrain tires?

 

https://tfltruck.com/2021/11/news-2022-chevy-silverado-4x4-mpg-estimates-drop-significantly-for-some-models-heres-why/

[Byrds8]

Checked that one. The tires on it are GYs. Looking at them on Discount Tire's web page, they weigh 1 lb more than the stock Sierra tires.

[Wiggums]

Exactly the same in size? 0.5 inch can make a big difference. Adding an inch affected my gas mileage by a good 10%.

[redwngr]

Part of the rating is the expected weight of the vehicle

The typical 'as sold' weights may have changed?  (only a guess...).

 

The 'average weight' argument was given as part of the reason given in '21 for the gmc verisions to have lower ratings than the chevs.

[Byrds8]

I believe they are the same weights. Looking at the title registration online it lists as 5230lbs. If memory serves, the other was the same.

 

As for tire size, yes. They "the same size." the Bridgestones were 33" even and the GY are 32.99.

[redwngr]

2 hours ago, Byrds8 said:

I believe they are the same weights. Looking at the title registration online it lists as 5230lbs. If memory serves, the other was the same.

 

As for tire size, yes. They "the same size." the Bridgestones were 33" even and the GY are 32.99.

I believe you are correct that the scale weights for '21 and '22 LTD, similarly equipped, will be the same.

The weight used for the fuel economy rating is based on some average weight of the vehicles sold or expected to be sold rather than a separate calc for each vehicle produced.

 

Knowledge how they sold for '21 may have made it necessary to adjust the weight for the calculation.   (more upper trims than expected?)

It's also possible the the fed regulation has changed the method to be used in the calc for '22 model yr....(more speed changes in the model, for example)

 

 

 

Edited March 22, 2022 by redwngr

[Byrds8]

8 hours ago, redwngr said:

I believe you are correct that the scale weights for '21 and '22 LTD, similarly equipped, will be the same.

The weight used for the fuel economy rating is based on some average weight of the vehicles sold or expected to be sold rather than a separate calc for each vehicle produced.

 

Knowledge how they sold for '21 may have made it necessary to adjust the weight for the calculation.   (more upper trims than expected?)

It's also possible the the fed regulation has changed the method to be used in the calc for '22 model yr....(more speed changes in the model, for example)

 

 

 

This is all correct. However, the SLT I had and the LTZ I currently have arent enough apart in features that would cause a signification weight gain. Even driving it the amount I have so far I can see it will not get the same MPG. Not to mention, the LTZ has DFM and the SLT did not. Just makes me wonder if something was changed that we cant physically see and GM didnt bother to say. It all just seems odd.

[MTU Alum]

It could be due to test weight class jump.  The EPA mass is the manufacturer must include any option that has a take rate over 33% in the vehicle mass that it certifies emissions and fuel economy.  Cheveolet typically uses LT model and GMC uses Denali.  If chevy is selling more highly contented vehicles, then the test weight class may jump which puts more load on dyno.  There is a bit of balancing act between selling more profitable vehicles and buying credits to offset the CAFE impacts.

 

#iworkforGM