Liking the 6.6 gas

Timu8 · July 3, 2020

Well folks, I gotta thank you all for the wise council on many sides of the debate. I took a plunge and traded my old Cummins for a GMC Sierra 6.6 gasser, I have not yet taken delivery but it is a crew cab 8 footer and the price was perfect. I will enjoy/suffer with my decision for a few years now and some of you will likely get to say ‘told you so’ . I live up north in Alberta and I guess I won’t need my Espar heater anymore. I got it in white, in Fort Mac that is the equivalent of camo for trucks as every second one is Contractor white, if I do something stupid, I’ll be harder to nail...

Limelight · July 24, 2020

Love how this tows! First chance to pull the camper to Western Md and over some hills. This new V8 eats it for lunch. The grade braking is also phenomenal- I feel it’s calibrated perfectly!

It seems the antigravity tires are working too. Lol

stupid iPhone

Timu8 · July 25, 2020

I’m looking forward to a couple of Alberta camping excursions with mine soon too! The dealership screwed up on my gooseneck install, and the kit is delayed or I would be posting my 6.6 gas experience too. Looking forward to early September when I can put it through the paces. It has an Andersen gooseneck hitch waiting in my garage for the under box rail kit to show up. I ditched the fifth wheel hitch so I can save some space and weight, my back is also looking forward to lifting 35 pounds instead of the crazy weight. Not sure mine will pull hills like your pic lol!

nick112288 · July 25, 2020

Has there been any more word on the supposed larger displacement gas engine?

I doubt that's the next update, I feel that will be 10 speed and rear end gearing

MORSNO · July 25, 2020

15 hours ago, nick112288 said:

Has there been any more word on the supposed larger displacement gas engine?

I doubt that's the next update, I feel that will be 10 speed and rear end gearing

The 6.6 is the new larger displacement engine. New transmission will surely follow.

nick112288 · July 25, 2020

23 minutes ago, MORSNO said:

The 6.6 is the new larger displacement engine. New transmission will surely follow.

Even after the 6.6 was announced, there was still a continuing rumor that a larger displacement engine was coming, 8+ liters of displacement.

Haven't seen much this year, and also some were speculating it was going to be a commercial only engine.

greatmizzou · July 25, 2020

8 litre gas with a 10 speed would be really awesome.

One thing about the 6.6 is the familiar platform and simplicity. If they make a big block and keep the same system id be sold. (And maybe a bigger fuel tank )

C/K Man · July 26, 2020

The 8L+ engine rumor started about a year ago, was widely reported but have not heard anything lately. My guess is that it's a commercial engine. The 6.6L is going into the LCF 3500/4500 Isuzu based trucks. Nothing about a gas engine for the Silverado medium duty yet.

nick112288 · July 26, 2020

2 hours ago, C/K Man said:

The 8L+ engine rumor started about a year ago, was widely reported but have not heard anything lately. My guess is that it's a commercial engine. The 6.6L is going into the LCF 3500/4500 Isuzu based trucks. Nothing about a gas engine for the Silverado medium duty yet.

I don't know if the gas towing spec war is as competitive as the diesel, but I can't help but feel like they'll need at least a 10 speed and rear gears to beat Fords max.

Sits at 16,940 vs 21,200

I'm not sure if rear end and 4 more gears will make up 4,260+ pounds

Carolina · July 31, 2020

On 6/24/2020 at 9:53 AM, redwngr said:

If fuel costs are a concern, be sure to understand the regular vs diesel pricing in the area the truck will live and work.

Today, Gas buddy shows that in your location (Ft McMurray) they are priced pretty much the same.

(Here, recently, many locations have been 5 or 6% cheaper for diesel. Typically, over the last few years, diesel has been 5 to 15% more than regular gas )

Much different than in some areas, where diesel cost is (in some cases significantly) more than regular.

I keep reading about 'significantly' higher diesel maintenance costs -- but that hasn't been my experience.

Compared to to fuel and finance costs on a new truck, maintenance costs aren't even on the radar.

Everyone I know suggests that a 1500 with a 5.3 or 6.2 will get significantly better mileage than a 6.0, when doing similar daily driver duties.

After running dmaxes for 10 years (LLY, LMM and LML) requirements changed and I tried running 1500's. Doing the same duties, I found that doing the same (mostly daily driver) work, the 1500's gave me about 10% better (20 usmpg, instead of 17.5 usmpg). I'm back in a 2500 diesel, not because of fuel but because I prefer the way they drive. I think the diesel gave better mileage towing, but don't have enough direct (same trailer, same load, same trip) comparisons to quote numbers.

Unless the 6.6 gas is significantly better on fuel than the 6.0, I'm not buying the arguments that the gas and diesel 6.6's will give the same mileage.

Is the 6.6 gas the right engine for lots of applications/lots of owners -- absolutely.

I currently own a 2020 6.6 , 2018 6.0 , 2009 Duramax and 2008 6.0 . The 2020 on factory 34”+ tires has the best fuel mileage non towing, the fastest, holds higher speeds on 7 % grades with the same trailer. The 09 is best towing mpg by 1 mpg , shifts the least in tow haul mode although the 2020 in man 5 ( same top gear as 09 in tow/haul) isn’t very far behind. 09 is the most comfortable to drive towing with cruise on in hills . 2018 moves loads from dead stop with the least amount of throttle, has much smaller tires 245’s is second with mpg non towing. The l5p 2020 will win them all over but the 6.6 gas is better than my 09 in my opinion

Edited July 31, 2020 by Carolina

Timu8 · August 27, 2020

Well having bought the 2020 GMC 2500 SLE gas 6.6, I have put 2300km on it empty, 3300 total incl. towing and the best fuel economy I could get so far was 12.1 l/100km, average so far 17.9l/100km that includes some 27.1 l/100km towing. The truck pulls my 9000# fiver with ease, revs higher than my diesels did, and I visit gas stations more often, but I really like it. It feels bigger than it is but I am getting used to it. I run a gooseneck with an Andersen adapter that is going to be eat better for my aging back, and toes much smoother than my previous fifth wheel hitch. Looking forward to a longer tow in Sept. Am I completely free of Duramax envy? -no! But I can honestly say that my rig tows excellently well even in the hills! Hope it gets even better once truly broke in. Anyone else got some towing experience with this gasser lately?

Edited August 28, 2020 by Timu8

Ray Pickle · August 27, 2020

On a trip as I speak from Cincinnati to Badlands, Grand Tetons, then Yellowstone. Have already done about 3000 miles towing in 2020 prior to this trip. Truck had 14500 miles on it as of today. Pulling a 37' 5th wheel.

6.6HD · August 27, 2020

Love this 6.6 gas. It tows like a boss. 6,000lb trailer and I cant even tell its back there.

The transmission shifts much better than the 6 speed from my '17. Clunk free shifting. Tight. Downshifting in trailer mode is perfect. Appears to not need a catch can as GM built a separator in.

It even sounds good.

Dunn · August 30, 2020

mine did break in and after 2k miles it feels more "lively" for sure

Timu8 · August 30, 2020

I’m hoping a couple of 9 hour tows in Sept and a couple thousand more kms and mine will be broke in too! I notice it passes very nicely at 3/4 throttle in a pinch, sounds good too!