Why is the listed gas mileage on newer LS models worse than LS models of just a few years ago?

( 20 versus 23 )

 

EPA changed their rules about 8 years ago on how they calculated gas mileage. All cars have a worse rating using that new system, but it is more realistic to what you'd actually get in real world driving.

Also, I wouldn't be that concerned about fuel economy if you're plunking down 80k+ on a V8 flagship.

 

welcome. at $3/gallon, 12K mi. a year, the difference in running cost between 20 and 23 is $234.

(600 gallons vs 522 gallons or 78 gallons more.)

 

It is not a money issue. I was wondering if there were performance changes or as pointed out, the method of calculating changed. I get a reliable 22-23 mpg in San Diego. Interesting that the EPA rules do not apply retroactively for comparison.

This is the reply I received from Lexus

Gas mileage from model year can vary based on the weight and aerodynamics of the vehicle, as well as the displacement of the engine and the octane fuel that it requires.

 

lexus reply is worthless.

epa tests are done by the manufacturer normally and they of course test each year, and the test likely changes each year, plus equipment level changes on cars. maybe the giant new grill is less aerodynamic.

 

If you compare a RWD 2015 LS to a 1998 LS:

2015 LS
City: 16
Hwy: 24
Comb: 19

1998 LS
City: 17
Why: 23
Comb: 19

So you gain 1 MPG HWY and lose one city which makes it a wash.

The 2015 LS also has considerably more power, its bigger and heavier. So the fact that it holds the line on economy is actually pretty good.

 

EPA tests changed in 2009 (or around that time), they became stricter and more reliable for customers to compare with their real life experience. So you would see same engine and vehicle doing different EPA numbers, in reality they are exactly the same just tests got better.

 

Welcome to CL as a new poster.

Among other factors, both curb weight and engine-displacement have risen over the years.....along with the change in EPA testing that others have mentioned.

 

Depending on your driving I've read on most reviews 19 is the average with a semi heavy foot. Even lower in some cases. It's a big heavy car that's for sure. Now the Lexus ES300H that makes 40 city/ 39 hwy. Pretty sweet.

 

the new EPA rating is pretty much right most of the time.. i use to get 25.5 mpg hwy on my GS430 when gas had no ethanol gas. Very hard to find 100% gas these days so i started using 10% ethanol gas.. I'm now getting 22 mpg hwy now which is the new EPA for my car.. What's not accurate is it says my combined should be 18, but i calculated my combined to 20mpg.. Its accurate for the most part.. but not 100% set in stone. I don't drive slow like grandpapi.. 80+ on the hwys and I kicked it around town a few times here and there.. and still get 20 mpg combined even when EPA say i should get 18mpg.. Do EPA only test Hwy? because their city and combined seems a little off..?