Why is MPG lower in G90 than other vehicles

[LBTX]

Folks, I recently purchased a 2021 G90 that so far I am quite happy with (although it does seem to be out of alignment). I knew the G90 had lower MPG than say Lexus or MB and I'm fine with that. Recently, though, I have started to wonder, why? Best I can tell the G90 is rated 3-4 MPG lower in highway than Lexus or MB. Why is MPG seemingly so much lower? It's not like Genesis or Hyundai just started making cars? I don't post this question as a critique, just curious as to why the G90 (not sure about other Genesis vehicles) are not as good as others in MPG. Any insight would be appreciated.

 

[EdP]

Folks, I recently purchased a 2021 G90 that so far I am quite happy with (although it does seem to be out of alignment). I knew the G90 had lower MPG than say Lexus or MB and I'm fine with that. Recently, though, I have started to wonder, why? Best I can tell the G90 is rated 3-4 MPG lower in highway than Lexus or MB. Why is MPG seemingly so much lower? It's not like Genesis or Hyundai just started making cars? I don't post this question as a critique, just curious as to why the G90 (not sure about other Genesis vehicles) are not as good as others in MPG. Any insight would be appreciated.

Good question. I'd start by looking at two big factors.
1. Weight. How much does each of the models weigh that you want to compare. Check overall length too
2. Performance. Start with engine size and also the 0 to 60 times.

I'm sure some of us here will be interested in what you find out on that.

 

[steveinarizona]

Folks, I recently purchased a 2021 G90 that so far I am quite happy with (although it does seem to be out of alignment). I knew the G90 had lower MPG than say Lexus or MB and I'm fine with that. Recently, though, I have started to wonder, why? Best I can tell the G90 is rated 3-4 MPG lower in highway than Lexus or MB. Why is MPG seemingly so much lower? It's not like Genesis or Hyundai just started making cars? I don't post this question as a critique, just curious as to why the G90 (not sure about other Genesis vehicles) are not as good as others in MPG. Any insight would be appreciated.

I have also noticed that but it is generally true across the Genesis line. Hyundai is relatively new to making luxury cars compared to companies like Mercedes and BMW and even compared to Lexus. So I have always assumed that Genesis has had less time to refine its engine and other components than its more established luxury competitors and, if one is in the ICE world, one needs to factor that into one's mental equations when comparing a Genesis to its competitors.

But, that is an assumption on my part and us old timers remember what Felix Unger said about assuming.

 

[rick3242]

What mileage are you getting? I replaced my Lexus LS460 with the 3.3 G90 and am getting much better milage? If I keep it under 65 I will get upper 20s.

 

[LBTX]

What mileage are you getting? I replaced my Lexus LS460 with the 3.3 G90 and am getting much better milage? If I keep it under 65 I will get upper 20s.

The Lexus is a 2013 LS460 with 145K. The car display tells me it is getting 19.4 MPG. It is my weekday driver - anywhere from 60-80 miles a day. The G90 says 17.1 or maybe 17.4, which somewhat approximates published data. The G90 is predominately city with a little highway, whereas the Lexus is highway with a little city. I would be thrilled to get 20MPG on either of my cars. Congrats to you! I'll have to keep an eye on the G90.

 

[LBTX]

I have also noticed that but it is generally true across the Genesis line. Hyundai is relatively new to making luxury cars compared to companies like Mercedes and BMW and even compared to Lexus. So I have always assumed that Genesis has had less time to refine its engine and other components than its more established luxury competitors and, if one is in the ICE world, one needs to factor that into one's mental equations when comparing a Genesis to its competitors.

But, that is an assumption on my part and us old timers remember what Felix Unger said about assuming.

I am wondering the same thing. If your assumption is correct - they have not yet had he time / experience to refine engine performance - it is impressive that they have been able to refine the interior to the level that they have. Oh and I loved the Odd Couple TV Show. Felix and Oscar were a hoot. I wonder if they got along with one another. I don't know how you could make such a funny show and not enjoy working with your partner.

 

[APS]

You have answered your own question. An ICE car is much more fuel efficient on the highway than in town. Electric is the reverse.

 

[EdP]

I am wondering the same thing. If your assumption is correct - they have not yet had he time / experience to refine engine performance - it is impressive that they have been able to refine the interior to the level that they have.

LX460 is 4244 pounds
G90 is 4861 pounds

 

[LBTX]

Good question. I'd start by looking at two big factors.
1. Weight. How much does each of the models weigh that you want to compare. Check overall length too
2. Performance. Start with engine size and also the 0 to 60 times.

I'm sure some of us here will be interested in what you find out on that.

Ed, why do I feel like you have given me a homework assignment? Please note that my sources have been cited So what does the data tell me? The LS500 and S500 do much better on highway than the g90 V6 (or V8 for that matter). S500 has much better combined of the V6's and the LS is not too much better than the G90 V6. On the v8 side, the S580 does better than the v8 g90, but is very similar to the V6's performance. Surprisingly the LS500 weighs more than MB and only slightly less than the G90 V8. I would have thought the MB would be heavier than all of the vehicles. Does that mean MB is using more high tech lighter materials or cheaper materials (I drove a S550 and the rear plastic rear window button snapped - that was an oops moment)? Is the G90 heavy because of high quality materials or they don't yet have the experience to take weight out?

So I guess the big takeaway is the G90 city MPG seems very similar to MB and Lexus. Highway performance is poor to the V6 competitors. Combined is not that bad except when compared to the S500. So all in all, maybe the G90 is not that bad in the MPG department except in the highway department. Audi and BMW probably need to be added to this table, but I don't know their models well enough. Ed, thanks for the assignment. Everyone, feel free to point any issues with the data if you see any.

	2021 G90 V6 AWD	2021 G90 V8 AWD	2021 S580	2021 S500	2021 LS500 AWD
Highway MPG	24	23	25	29	27
Ciy MPG	17	16	17	20	17
Combined MPG	20	18	20	24	21
Weight	4,806	4,960	4,775	4,610	4,905
Length	204.9	204.9	208.2	208.2	206.1
0-60	5 secs		4.4 secs	4.8 secs	4.6 secs
	https://www.caranddriver.com/genesis/g90/specs/2021/genesis_g90_genesis-g90_2021/417760		Used 2021 Mercedes-Benz S-Class Specs & Features | Edmunds Detailed specs and features for the Used 2021 Mercedes-Benz S-Class including dimensions, horsepower, engine, capacity, fuel economy, transmission, engine type, cylinders, drivetrain and more. www.edmunds.com		https://www.caranddriver.com/lexus/ls/specs/2021/lexus_ls_lexus-ls500_2021/418348
			https://www.caranddriver.com/merced...enz_s-class_mercedes-benz-s-class_2021/419591

 

[LBTX]

Sorry for the poor table, but I couldn't get it to paste properly.

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[EdP]

Ed, why do I feel like you have given me a homework assignment? Please note that my sources have been cited So what does the data tell me? The LS500 and S500 do much better on highway than the g90 V6 (or V8 for that matter). S500 has much better combined of the V6's and the LS is not too much better than the G90 V6. On the v8 side, the S580 does better than the v8 g90, but is very similar to the V6's performance. Surprisingly the LS500 weighs more than MB and only slightly less than the G90 V8. I would have thought the MB would be heavier than all of the vehicles. Does that mean MB is using more high tech lighter materials or cheaper materials (I drove a S550 and the rear plastic rear window button snapped - that was an oops moment)? Is the G90 heavy because of high quality materials or they don't yet have the experience to take weight out?

So I guess the big takeaway is the G90 city MPG seems very similar to MB and Lexus. Highway performance is poor to the V6 competitors. Combined is not that bad except when compared to the S500. So all in all, maybe the G90 is not that bad in the MPG department except in the highway department. Audi and BMW probably need to be added to this table, but I don't know their models well enough. Ed, thanks for the assignment. Everyone, feel free to point any issues with the data if you see any.

	2021 G90 V6 AWD	2021 G90 V8 AWD	2021 S580	2021 S500	2021 LS500 AWD
Highway MPG	24	23	25	29	27
Ciy MPG	17	16	17	20	17
Combined MPG	20	18	20	24	21
Weight	4,806	4,960	4,775	4,610	4,905
Length	204.9	204.9	208.2	208.2	206.1
0-60	5 secs		4.4 secs	4.8 secs	4.6 secs
	https://www.caranddriver.com/genesis/g90/specs/2021/genesis_g90_genesis-g90_2021/417760		Used 2021 Mercedes-Benz S-Class Specs & Features | Edmunds Detailed specs and features for the Used 2021 Mercedes-Benz S-Class including dimensions, horsepower, engine, capacity, fuel economy, transmission, engine type, cylinders, drivetrain and more. www.edmunds.com		https://www.caranddriver.com/lexus/ls/specs/2021/lexus_ls_lexus-ls500_2021/418348
			https://www.caranddriver.com/merced...enz_s-class_mercedes-benz-s-class_2021/419591

You did well on the assignment.
Weight is a factor, of course, but you bring up a good question. Is a heavier car better constructed or has more features? Or is it just easier and cheaper materials? Pennies count in building a car so that may be a big factor in the end.

 

[steveinarizona]

You did well on the assignment.
Weight is a factor, of course, but you bring up a good question. Is a heavier car better constructed or has more features? Or is it just easier and cheaper materials? Pennies count in building a car so that may be a big factor in the end.

Probably a mixed bag. Steel is cheaper than aluminum but aluminum is lighter. Titanium and Inconel are stronger than steel but much more expensive. A V8 typically weights more than a V6 or straight 6 which in turn typically weights more than a 4 cylinder engine. More battery capacity in an EV equals more weight but less range. Etc. There are tradeoffs throughout the process.

I agree with LBTX that it is impressive how far and how fast Genesis has gone in design and manufacturing. I purchased my GV60P a year and a half ago because no one else produced a car that came close to meeting my desires at that time and I was a BMW owner. Now, a year and a half later, I still think my car is stupendous and expect it to be even more so this afternoon when I finally dump my Michelin Primacy tires for Pilot 4S tires.

 

[EdP]

Probably a mixed bag. Steel is cheaper than aluminum but aluminum is lighter. Titanium and Inconel are stronger than steel but much more expensive. A V8 typically weights more than a V6 or straight 6 which in turn typically weights more than a 4 cylinder engine. More battery capacity in an EV equals more weight but less range. Etc. There are tradeoffs throughout the process.

I never understood why airplanes are made out of aluminum. Cast iron is cheaper and stronger.

Will be interesting to hear the results of your tire change.

 

[Trixie86]

I have also noticed that but it is generally true across the Genesis line. Hyundai is relatively new to making luxury cars compared to companies like Mercedes and BMW and even compared to Lexus. So I have always assumed that Genesis has had less time to refine its engine and other components than its more established luxury competitors and, if one is in the ICE world, one needs to factor that into one's mental equations when comparing a Genesis to its competitors.

But, that is an assumption on my part and us old timers remember what Felix Unger said about assuming.

Ha, loved Oscar

 

[SuperKing]

Genesis cars are just heavy. Hyundai is still a noob at making luxury cars and lack the experience working with different materials. To get that solid feel, Hyundai opted for high strength steel because it's just easier and it's cheaper since Hyundai owns the mines and refineries. Meanwhile the 7 Series is a combination of carbon fiber and steel.

If Hyundai started using carbon fiber in the frame of their cars, it would probably cost as much as the 7 Series and if that happens, the main reason why people would buy a Genesis disappears. Honestly, the fuel economy isn't that bad. I've had as low as 8L/100Km which is just over 29mpg in my 5.0L on highways. It's horrible in the city but it doesn't matter to me as much. I live 6km from work so I drive less than 300km a month. A tank of gas lasts me roughly 6 weeks.

 

[LBTX]

Genesis cars are just heavy. Hyundai is still a noob at making luxury cars and lack the experience working with different materials. To get that solid feel, Hyundai opted for high strength steel because it's just easier and it's cheaper since Hyundai owns the mines and refineries. Meanwhile the 7 Series is a combination of carbon fiber and steel.

If Hyundai started using carbon fiber in the frame of their cars, it would probably cost as much as the 7 Series and if that happens, the main reason why people would buy a Genesis disappears. Honestly, the fuel economy isn't that bad. I've had as low as 8L/100Km which is just over 29mpg in my 5.0L on highways. It's horrible in the city but it doesn't matter to me as much. I live 6km from work so I drive less than 300km a month. A tank of gas lasts me roughly 6 weeks.

SK thanks for the insight!

 

[Backslack]

The discrepancy is because it's an older car. The G90 you're driving originally came out in 2015 - and some of the engine choices like the 420 HP 5.0 V8 date back to the Hyundai Genesis which in that generation came out in 2013. The current G90's fuel economy is pretty much identical to the LS.

Compare Side-by-Side

Compare the MPG of cars and trucks side-by-side. Compare the gas mileage and greenhouse gas emissions of new and used cars and trucks

www.fueleconomy.gov

Weight between all the flagships are pretty much the same, the difference is that because Genesis bundles all the options standard, those are included as part of the official weight whereas the Germans only show off the weight of the stripper base models. The Germans are more efficient with their engines because they use lower displacement (3L vs 3.5L for the Genesis and Lexus) and higher boost. Some like BMW also use cylinder deactivation in the latest version of the B58. The problem is that all this generally this doesn't bode as well for long-term reliability.

 

[LBTX]

The discrepancy is because it's an older car. The G90 you're driving originally came out in 2015 - and some of the engine choices like the 420 HP 5.0 V8 date back to the Hyundai Genesis which in that generation came out in 2013. The current G90's fuel economy is pretty much identical to the LS.

Compare Side-by-Side

Compare the MPG of cars and trucks side-by-side. Compare the gas mileage and greenhouse gas emissions of new and used cars and trucks

www.fueleconomy.gov

Weight between all the flagships are pretty much the same, the difference is that because Genesis bundles all the options standard, those are included as part of the official weight whereas the Germans only show off the weight of the stripper base models. The Germans are more efficient with their engines because they use lower displacement (3L vs 3.5L for the Genesis and Lexus) and higher boost. Some like BMW also use cylinder deactivation in the latest version of the B58. The problem is that all this generally this doesn't bode as well for long-term reliability.

Good points about the age of the G90 engine and the stripped down weight of the MB. Thanks for taking the time to share your insight.