[engineerrs]

V6 3.0L 340hp, 6.8 0-60
City: 17
Highway: 23
Mixed: 19

V8 5.0L 518hp, 5.0 0-60
City: 17
Highway: 22
Mixed: 19

I can't find any info online on how they managed to pull that off. Cylinder deactivation makes sense for almost matching the V6's highway mileage, but I'm curious how they're matching the city and mixed.

Any ideas?

 

[doc5339]

Just an idea: perhaps the torque (both torque and horsepower are improved in this 2019 engine) available at the lower-end of the RPM-range supports similar efficiency to the V6 SC because the V8 SC uses less fuel to get the significant mass of the SUV rolling.

I did a cursory search of the new 518hp 5.0 V8 SC, it did not yield any illuminating details such as: cylinder deactivation, continuous variable valve timing improvements, or addition of compression ignition. JLR may have just improved cooling, supercharger efficiency, timing, etc in order to squeeze-out more power and torque?

Coming from Jeep JKUs, many owners had dramatic MPG improvements or at least similar MPG (depending on mods) when swapping to GM Gen IV and Gen V V8 power trains when keeping all other modifications the same.

There is definitely a smarter way to articulate this, so apologies for my crude expression. The added low-end power probably uses fuel more efficiently than a higher-revving V6 or V6 SC (many JK and JKUs utilize aftermarket superchargers) when accelerating from a stop, slow speed, uphill etc.

The fuel economy numbers you posted are just EPA estimates, and do vary based on a myriad of factors. My idea is that JLR simply hit a "sweet spot" of torque, power, and weight with the 2019 518hp V8 SC since the aerodynamics of the V8 and V6 models are likely very similar.

 

[Mancerator]

2017 Sport Supercharged V8 rated at 510 hp, 461 torque and gas mileage of 14 city, 19 highway. 2018 and 2019 V8s both rated at 518 hp, 461 torque and gas mileage of 17 city 22 highway. All three years weigh about the same (just over 5000 lbs) which of course will vary with options and equipment and all with mfg stated 0-60 times of 5.0 seconds. Since the RR V8s have more than adequate power and torque one possibility could be a slight change in gearing from 2017 to 2018/19. I too think the lower torque of the V6's means they work harder to move 5000 lbs which can affect mpg.

 

[Hodog16]

Amazing if true. I don’t mind the gas mileage with the V8 but those numbers are much better.

It’s a shame the rumor is LR will not use this V8 in the next gen.

 

[gotzillar]

I don't know how they achieved that during EPA testing and I don't believe it because during my test drive on a 2018 V8, I got 15mpg with my gentle foot in a mix of highway and city.

 

[totya]

For '18 the terrain response on-road modes were seriously reprogrammed. The comfort mode the cars now default to is nowhere near as angry as the normal mode used to be in '17 and before. I can very well believe that there's a significant difference between the '17 and the '18/19 mpg with the default settings and with the same driver.

 

[engineerrs]

The theories that the greater low end torque and remapped throttle response have decreased fuel consumption make sense. I'm going to go into LR today and see if they know.

 

[leftlanetruckin]

It isn't rocket science. More available power, less your foot is in it.
I've done countless motor swaps where more HP/cylinders/torque equaled more MPG.
Same in my daily driver, that I always get the most hp/torque available.....and get better fuel mileage than the fleet spec junk with less.

Martin

 

[engineerrs]

Went to the dealership and asked them and they said it might have to do with weight reductions. I asked if that would apply to the V6 model thus increasing the fuel economy on that too and was told maybe.

I test drove both back-to-back on the freeway and pulled mpg data cruise controlling just under 65mph for about a mile or so (too much traffic to go faster):

V6: 26.5mpg
V8: 22.5mpg

 

[engineerrs]

I rented a 2016 V8 RRS ATB for the weekend and did some tests.

On a (mostly) flat road:

72mph: 25mpg
75mph: 24.2mpg
77mph: 23.8mpg

City fuel economy isn't great with light throttle netting 13-15mpg, but it seems even the pre-facelift L494's get much better fuel economy than what LR rate them for.

 

[amm]

Interesting. Are you all doing the math based on miles driven and fuel consumed (how much gas is pumped in at the gas station) or are you citing the numbers that are displayed in the onboard trip computer?

I would offer that the onboard numbers are typically 1-3 MPG optimistic in my experience FWIW.

 

[engineerrs]

Interesting. Are you all doing the math based on miles driven and fuel consumed (how much gas is pumped in at the gas station) or are you citing the numbers that are displayed in the onboard trip computer?

I would offer that the onboard numbers are typically 1-3 MPG optimistic in my experience FWIW.

Good point. I'm going based on the displayed fuel economy. I'd go back and retest, but I returned the vehicle yesterday.