Road Trip results in Worst and Best MPG's so far

I just got back on a 550 mile road trip with the Genesis. The 1st day I went from my home in Andover, MN to Tofte MN to go hiking at Carlton Peak that overlooks Lake Superior. This was 230 miles, and I averaged 28.1 mpg @ a cruise control set 71 mph according to the GPS, which is actually my worst highway MPG's since I bought the car 2.5 years ago. Usually I get between 29 - 30 mpg highway.

The fuel used was Premium 91 octane from Kwik Trip Top Tier fuel.

From Tofte, MN I drove to Grand Marias MN (total of 28 miles, Tofte to Grand Marias) ending about 30 miles south of the Canadian border. I had fun driving this one, since view is amazing and the roads are super fun. Had a few small curves in the road overlooking Superior and cliffs and the Genesis was blast to drive this road, handling like a Gem 100 mph plus.

Headed from Grand Marias to Duluth for some night life in Canal Park and stayed the night. Before leaving back home, I found a BP station and filled up a full tank of Premium 91 Octane, which IS WIERD since the BP by my house carries Premium with 93 Octane. Anyhow, The trip from Duluth to Andover I had the cruise set at 71 mph per the GPS and results were 31.1 average mpg, which is the best so far with the car. Temp was 60 degrees and sunny on the way back to the twin cities. Way up to Tofte weather was about 50 degrees and partly cloudy.

The only problem I had was a rock chip acquired on my windshield, but at least that's what glass coverage is for, so I will have the chip filled in tomorrow. It's right at the bottom of the windshield about 5 inches or so from the bottom, and in the center, so it's not going to bother me if there is a tiny spec left once it's filled it by the glass company.

Overall Genesis, performed excellent, and was very comfortable. Suspension handled the roads great, no matter smooth or a concrete section 50 miles plus with expansion joints every 10 feet or potholes. Love the seats. I find the most comfortable setting on the driver seat for me is to have everything deflated, with no lumbar support etc. My tires we filled up to 33 psi to the vehicle's specs. I usually run them at around 30 or 31, but for fuel economy purposes 33 psi.

Amazing mpg for such a powerful car.

Very good mpg. Our average is always 24 to 25. however its almost always has city driving in the mix. Next time on I75 from Atlanta to near the Florida line we will check it on just the highway section of the trip.

Can I ask why you run premium gas? Just curious.

yellow3.8track said:

Can I ask why you run premium gas? Just curious.

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A few reasons -

1. Premium fuel produces 7 more HP on this engine vs regular (not the V6).

2. It actually costs more money for me to run Regular because I get better MPG's with premium. I noticed this when I 1st bought the car, and now run Premium every fill.

scottdk said:

A few reasons -

1. Premium fuel produces 7 more HP on this engine vs regular (not the V6).

2. It actually costs more money for me to run Regular because I get better MPG's with premium. I noticed this when I 1st bought the car, and now run Premium every fill.

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I tried regular a few months ago for the first time and didn't see any significant difference in fuel economy. There's also a post in this thread that says that there's no advantage to using premium (other than boosting performance in the 4.6).

How much of a difference have you seen? Thanks.

scottdk said:

A few reasons -

1. Premium fuel produces 7 more HP on this engine vs regular (not the V6).

2. It actually costs more money for me to run Regular because I get better MPG's with premium. I noticed this when I 1st bought the car, and now run Premium every fill.

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just completed an 800 miles trip from florida to Virginia tonight. regular 87 octane at 81mph cruise set light to no traffic and hand calculated 26.5 (dic showed 27.3) also got 513 miles out of one tank and it took 19.2 gallons.

for comparison my '10 Yukon Denali with the 6.2 and "AFM" only got 15.6mpg at the same speed on same trip in November. what a difference (on 93).

unlike yourself i have noticed zero change in mpg from 93-87 octane.

i think that's amazing for this heavy car and a v8 without DI or DOD technology??

don't know if you saw my post where i set the cruise at 55mph car was getting 31.5mpg (dic, so probably 30.7 or so) and my car only had 1500 miles at the time (has 2400 now).

One of the challenges in measuring fuel economy is knowing how much was really consumed between fill-ups. From what I've read, the gas pump cuts off when a hole near the end of the nozzle becomes covered by fuel, stopping the flow of air through a sensing pipe. So the amount of gas you can get into the tank depends on the precise position of this hole relative to the filler pipe, which is why you can usually add a bit more by pulling the nozzle back a bit.

It'd be interesting to know how much the amount of fuel pumped varies because of this. Probably not much, but I don't know for sure.

You didn't mention the bathroom breaks? Were they successful? Did you use 2 or 4 ply?

flyboy2 said:

You didn't mention the bathroom breaks? Were they successful? Did you use 2 or 4 ply?

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Actually, I did stop at a Subway for a bite to eat and to unleash the fury before driving off again. It went well.

As for #2, I use the 4 ply of course! I want performance, not a cheap product

My point to this thread was to highlight the comfort of my trip and how much fun this car is, but also to show decent MPG's for such a powerful car. This was not another regular vs premium post, as it was never mentioned. I only mentioned that I ran premium because I figured someone would ask.....

I'm the kind of guy who would run regular, and has in the past with other cars, but this is the only vehicle I've owned that sips less fuel on premium in my own experiences.

I asked about the gas because I've heard from others that they get better mpg from premium.

My dad's 2004 GMC 4WD full size pick up (5.3 liter with automatic transmission) is run with premium when they take it on a trip. He told me they go 23 mpg on a trip to Indiana a few years back. They don't travel much these days but he said his S10 4WD PU also got better gas mileage on premium.

I'll try it on my coupe after I get a few trips documented on regular.

scottdk said:

My point to this thread was to highlight the comfort of my trip and how much fun this car is, but also to show decent MPG's for such a powerful car. This was not another regular vs premium post, as it was never mentioned. I only mentioned that I ran premium because I figured someone would ask.....

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I know that was your original point - it was your comment about specifically getting better MPG with premium than regular and the question of how to accurately measure mileage that got me wondering.

Anyway, I think that it's great that you're getting such good fuel economy. Although a good part of my driving is at freeway or near-freeway speeds, I only get around 20-21 MPG. But my first road trips of any length are coming up, and I'm going to see if I can do better.

BTW, in your experience, how noticeable are windshield chips after they're filled in? I had a couple in my last car and left them alone, though they still bothered me at times.

waveman said:

I know that was your original point - it was your comment about specifically getting better MPG with premium than regular and the question of how to accurately measure mileage that got me wondering.

Anyway, I think that it's great that you're getting such good fuel economy. Although a good part of my driving is at freeway or near-freeway speeds, I only get around 20-21 MPG. But my first road trips of any length are coming up, and I'm going to see if I can do better.

BTW, in your experience, how noticeable are windshield chips after they're filled in? I had a couple in my last car and left them alone, though they still bothered me at times.

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Thanks for your input Wave -

I've had windshield chips filled in before and I think it just depends on the location of the chip. The wife had one right in her point of view, so we would always notice the clearish dot in the line of site, and it bothered the hell out of both my wife and myself.

I think as long as the repair isn't in the line of sight, then everything should be just fine.

V6 - Tech Package: I set the cruise on 61 mph with windows cracked (no AC) on I10 and I75 through Florida and managed a calculated 31.2 MPG (DIS 32 something).
Driving normal apx. 75mph with A/C I usually get 28/29 on the same stretch.

A little off topic, but I average 25MPG most all the time 50/50 city/highway and if I feel the need to drive aggressively I have dropped it to 18/19 mpg.

NOTE: Regular gas only but it seems BP get better mpg than off brands...

I drove from San Diego to Phoenix and back this week and here are my results. Mind you I am in a 2009 3.8 with Tech and Premium packages. On the way there we had a strong tailwind OR crosswind the entire way. I filled up near the house and drove 469 miles before the gas light came on. (I had some city driving to do in PHX while I was there.) I used the standard 87 octane. It took 17.3 gallons. I had cruise ocntrol at between 80-85mph with a couple of short restroom stops. I had myself and my girlfriend and a trunk full of stuff with us. That gives me something near 27mpg. On the way home we had a strong headwind/crosswind and I cruised between 78-82mph and only got 410miles out of the tank. It took 17.7 gallons. I am sure that I could have gotten better mileage if we would have driven slower and had less stuff with us, but that is the way it is when travelling with your lady.... You have to haul all her sh1t around and then can't get to your destination fast enough so that you can get out of the car!

I sell a special injection kit for whoever would like to increase their mileage. Let me know-- Only $1,250 installed.

Flyboy

Group buy discount.........?

Reading the mileage claims here leaves me a bit depressed. My 2011 3.8 fully loaded gets no more tha 19-20 mpg at 50/50 city/hwy driving. And I'm a cautious driver. Took it back to the dealer and they found nothing wrong to account for lower mileage.

treat2 said:

Reading the mileage claims here leaves me a bit depressed. My 2011 3.8 fully loaded gets no more tha 19-20 mpg at 50/50 city/hwy driving. And I'm a cautious driver. Took it back to the dealer and they found nothing wrong to account for lower mileage.

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My 2010 3.8 gets ~22-23 mpg on my daily commute (half highway, half surface streets) and ~28-29 mpg on trips.