2015 GMC Yukon XL Denali MPG (6.2L, 8-speed)

[MPond]

We did our first road trip last weekend in our new 2015 GMC Yukon XL Denali with the 6.2L and the new 8-speed transmission. Towed my brother's boat to AZ, no trailer on the return trip. And I was really happy with the MPG both towing and not towing.

On the way out to AZ I averaged 11.4 MPG, while towing the 7,000 lb boat, including pulling the grades at 65-70 MPH - kept my foot in it to see what the new truck would do.

On the return trip (no trailer, but loaded with 5 people and the cargo area full of gear for the long weekend) I averaged 20.1 MPG over 300 miles. Because of traffic my average speed was down to 65 MPH, and I made it home from AZ on 15 gallons. In a truck making 420hp / 460 lb-ft of torque.

Thanks to the 8-speed and the next generation of Cylinder Deactivation, this truck is getting nearly twice the MPG I was getting in my 8.1L Suburban.

[Dadoffourgirls]

Just a note on premium and the DIC on my CTS. My hand calculated mileage is higher than the DIC when using 93 octane instead of 87. This is on the 2.0 Turbo. I believe that my butt-dyno does say that premium is better, and the Shell station sells 93 octane for $.20 more than 87. The mpg is about 1.5 better with 93 octane.

[Dave_H_M]

Holy mackrel, that just beats the stuffings out of the mileage I get with the 6.2 F250. :R

[MPond]

N-Trouble wrote:
Are these hand calculated values or off the dream-o-meter? What grade of fuel you have to run?

My first 2 tanks were 87 (before I read that 91 was recommended). Since then I've been running 91, and my butt-dyno says it runs a bit stronger on 91 - but who really knows. I think it's enough of a difference that I'm spending my own $$$ to buy 91 instead of 87. Putting my money where my mouth is there...

As far as hand-calculated vs. the DIC - my initial comments were from the DIC, but I have the gas station receipt and it's not hard to figure out...

I reset the DIC when I filled up on my way out of Arizona, and the DIC was showing 20.1 MPG for 301.0 miles when we got home Monday night.

The next morning on my way to work I got gas and it took 15.3 gallons. A quick Google Map search shows that gas station is 5.2 miles from my home, so 306.2 miles / 15.3 gallons = 20.03 MPG. Given that I was rushing on the way to work and driving pretty fast, I'm not surprise that my MPG dropped from 20.1 to 20.0 MPG.

So in this case the DIC was pretty accurate.

The DIC was always incorrect in my old Suburban, so I'll keep checking this one...

[N-Trouble]

Are these hand calculated values or off the dream-o-meter? What grade of fuel you have to run?

[nevadanick]

The mileage didnt change on ours. It was good from the get go and when i got rid of it, it was still getting the same. You can buy them well below msrp, ours was 72 and some change msrp and i paid 63.

[MPond]

I don't want to start a debate with the weight police, but I will say this:

While the new GMC isn't rated for as much weight as the old Suburban, I do think it could handle it if properly equipped (tire ratings, etc...).

In terms of stability, braking, on-road handling, etc..., it feels as stout as my 3/4 ton Suburban.

Not that you should, but I bet you could... :B

[MPond]

BurbMan wrote:
No doubt, it's a nice looking truck all around, and the fuel mileage with the 8-speed is truly impressive.

My issue is that our TT is 8500 lbs with 1200 on the tongue, so would definitely put us overweight. Have been thinking of the new Ram trucks, but we still use the 3rd row in the burb now and again, so not ready to pull the trigger yet,. I figure I've got a few more years to decide, and it might be 5er time them...

...

I agree with you there. If I had been using my old Suburban to tow our larger trailers, I'd have held off on the new GMC. But I use it mostly for trips to the river, and for towing boats or my flatbed trailer with the Jeep on it - both well within it's ratings.

[MPond]

Campfire Time wrote:
Thanks for posting this. I'm really intrigued by the 6 & 8 speed transmissions. My truck missed the 6 speed by a couple of years.

My dad has the Cadillac Escalade ESV with the 6.2 & 6-speed, and although it's not quite as good as my new truck (newer version of the 6.2 and 2 more gears), it's still night & day better than the old 4-speed in terms of MPG and usable power.

We've done a bunch of side-by-side comparisons between his Caddy and my Suburban before I sold it; we'll do a comparison of the Caddy to my GMC on our next trip to AZ, as neither of us will be towing.

[BurbMan]

MPond wrote:
Yeah, you're right. I'd been sitting on my old 8.1L Suburban 2500 for exactly that reason - GM hadn't offered anything comparable for a while. Although the new one isn't rated as high as the old 2500, you wouldn't know it by driving it or towing with it. Everything about it feels as good or better, from the brakes, to the driveline and chassis - I'm very happy with it.

Fortunately, I use this truck primarily for towing boats. For the larger trailers I usually use my 3500 dually. So that lower limits don't affect me much.

I thought people might find the MPG interesting, as you'll likely see the drivetrain in more GM vehicles over the coming year or two.

No doubt, it's a nice looking truck all around, and the fuel mileage with the 8-speed is truly impressive.

My issue is that our TT is 8500 lbs with 1200 on the tongue, so would definitely put us overweight. Have been thinking of the new Ram trucks, but we still use the 3rd row in the burb now and again, so not ready to pull the trigger yet,. I figure I've got a few more years to decide, and it might be 5er time them...

My burb is fully optioned and the sticker was about $46k back in 2001....maybe it's been too long since I've bought a vehicle, but that $79k made my eyes burn....

[Campfire_Time]

Thanks for posting this. I'm really intrigued by the 6 & 8 speed transmissions. My truck missed the 6 speed by a couple of years.

[MPond]

And FYI for anyone who is looking for one...

The 2015's still had the 6-speed. The 2015.5's have the new 8-speed.

[MPond]

Tystevens wrote:
Thanks for the post, OP. Sounds like a great vehicle. Our best tank ever in our 2010 5.3 was 21.5 (avg speed about 63 mph) on a back roads trip. Incredible that GM is getting the same mpg with 100 more hp! The Yukon XL 6.2 is definitely in contention to replace our Suburban in a year or two.

😄 I haven't had many "best tanks" yet - only have 2000 miles on the new truck. But I have done a couple short 75 mile trips completely unloaded (no gear, no trailer, and only myself and 1 passenger) and got 22 MPG on those trips. But not really long enough to be indicative.

I wonder if the MPG will change as the engine breaks in further?

[MPond]

BurbMan wrote:


According to the GMC website, the starting MSRP for 4WD is $71,415. With a few options tossed in, I had no trouble getting the MSRP to just shy of 80 large...

IMHO it's worth it. This truck is night and day better than the last one I had, whether talking about interior features, comfortable seats, or overall performance.

BurbMan wrote:


...With this new drivetrain, it's almost as capable as the old 2500 was in terms of towing, although still light on payload. I'll bet the OP was close to GVWR with passengers, cargo, and tongue weight of the boat in tow. If that had been a 7000 lb travel trailer, he would have been over weight for sure.

Curb Weight (lbs.) 5981 lbs
Max Payload (lbs.) 1519 lbs
GVWR (lbs.) 7500 lbs
Max Trailering (lbs.) 7900 lbs

All in all, a very nice truck!! Congrats to the OP and good luck with it!!

Yeah, you're right. I'd been sitting on my old 8.1L Suburban 2500 for exactly that reason - GM hadn't offered anything comparable for a while. Although the new one isn't rated as high as the old 2500, you wouldn't know it by driving it or towing with it. Everything about it feels as good or better, from the brakes, to the driveline and chassis - I'm very happy with it.

Fortunately, I use this truck primarily for towing boats. For the larger trailers I usually use my 3500 dually. So that lower limits don't affect me much.

I thought people might find the MPG interesting, as you'll likely see the drivetrain in more GM vehicles over the coming year or two.

[Tystevens]

Thanks for the post, OP. Sounds like a great vehicle. Our best tank ever in our 2010 5.3 was 21.5 (avg speed about 63 mph) on a back roads trip. Incredible that GM is getting the same mpg with 100 more hp! The Yukon XL 6.2 is definitely in contention to replace our Suburban in a year or two.