Jump to content

Liking the 6.6 gas

Carolina

By Carolina
in 6.6L Gas V8 (L8T)

 Share

Recommended Posts

Timu8 Enthusiast

Timu8

Posted
Posted

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... 

  • Like 3
  • 3 weeks later...
  • Replies 140
  • Created
  • Last Reply

Top Posters In This Topic

Popular Days

Top Posters In This Topic

Popular Days

Popular Posts

Ray Pickle
Ray Pickle

I am halfway thru my trip from cincinnati to big pine key florida, first tank in driving rain 8 mpg, 2nd tank 8.9 3rd tank 9.1 4th tank 9.3. I will be returning home in a week and will update. I am to

Carolina
Carolina

I just finished a 600 mile round trip from Sc thru NC and TN mountains towing 9130 pounds . Interstate grades were a 3 mile 6% , 1 mile 7 % ,  6 mile 7% and a few 10% backroad grades . I can say I was

Carolina
Carolina

So have you towed with one or you just watched the IKE pull and know everything about it now? You ever thought about the fleet perceptive ? The 6.0 is one of the most respected engines for HD service

Posted Images

Limelight Enthusiast

Limelight

Posted
Posted

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

 

DD251FC1-2DD7-4339-8F2B-EA81145F6DE1.jpeg

  • Thanks 1
Timu8 Enthusiast

Timu8

Posted
Posted

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 Enthusiast

nick112288

Posted
Posted

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

  • Thanks 1
MORSNO Enthusiast

MORSNO

Posted
Posted
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 Enthusiast

nick112288

Posted
Posted
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 Enthusiast

greatmizzou

Posted
Posted

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 Enthusiast

C/K Man

Posted
Posted

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 Enthusiast

nick112288

Posted
Posted
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 Enthusiast

Carolina

Posted
  • Author
Posted (edited)
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 by Carolina
  • Like 2
  • Thanks 2
  • 4 weeks later...
Timu8 Enthusiast

Timu8

Posted
Posted (edited)

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 by Timu8
Ray Pickle Enthusiast

Ray Pickle

Posted
Posted

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.

  • Thanks 1
6.6HD Enthusiast

6.6HD

Posted
Posted

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.

 

 

  • Thanks 1
Dunn Senior Enthusiast

Dunn

Posted
Posted

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

  • Thanks 1
Timu8 Enthusiast

Timu8

Posted
Posted

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!

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing

  • Latest Articles

  • Posts

    • Another JR
      Gasser Subforum Has Been Quiet - - So, Regenerative Braking and Using L10

      By Another JR · Posted

      Have considered installing a DC to DC charger in your camper to replace your isolator?  
    • newdude
      Gas fill door

      By newdude · Posted

      Common failure.  You need to replace the fuel door housing.   The painted cover transfers over to the new housing.  To remove the old one there is 4 spots where you poke the plastic to release it.  
    • newdude
      Gasser Subforum Has Been Quiet - - So, Regenerative Braking and Using L10

      By newdude · Posted

      No such thing as regenerative braking on a pure ICE vehicle.     Regenerative braking is the re-capture of energy from electric motors and stores it in the battery pack.  So hybrids, PHEV and EVs have regenerative braking.     What you are seeing is the charging system changing modes is all.  Its likely entering charge mode for some sort of reason is all.  All of the charging modes will be listed below.   As for L10 vs D.  L10 turns off automatic grade braking.  L10 puts you in control of grade downshifts where in D it will automatically do it based on brake pedal position and other factors.  Otherwise L10 and D drive exactly the same aside from that one aspect.    Battery Sulfation Mode The BCM will enter this mode when the interpreted Generator output voltage is less than 13.2 V for 45 minutes. When this condition exists the BCM will enter Charge Mode for 2–3 minutes. The BCM will then determine which mode to enter depending on voltage requirements.   Charge Mode The BCM will enter Charge Mode when ever one of the following conditions are met:   Windshield wipers are ON for more than 3 s. Climate Control Voltage Boost Mode Request is true, as sensed by the HVAC control module via serial data. High speed cooling fan, rear defogger, and HVAC high speed blower operation can cause the BCM to enter the Charge Mode. The estimated battery temperature is less than 0°C (32°F). Battery State of Charge is less than 80%. Vehicle speed is greater than 145 km/h (90 mph) A current sensor malfunction exists. System voltage is determined to be below 12.56 V When any one of these conditions is met, the system will set targeted generator output voltage to a charging voltage between 13.9–15.5 V, depending on the battery state of charge and estimated battery temperature.   Fuel Economy Mode The BCM will enter Fuel Economy Mode when the estimated battery temperature is at least 0°C (32°F) but less than or equal to 80°C (176°F), the calculated battery current is less than 15 A and greater than −8 A, and the battery state-of-charge is greater than or equal to 80%. Its targeted generator output voltage is the open circuit voltage of the battery and can be between 12.5–13.1 V. When fuel economy mode is active, the generator is not charging, only maintaining open circuit battery voltage. The BCM will exit this mode and enter Charge Mode when any of the conditions described above are present.   Headlamp Mode The BCM will enter Headlamp Mode when ever the head lamps are ON (high or low beams). Voltage will be regulated between 13.9–14.5 V.   Start Up Mode When the engine is started the BCM sets a targeted generator output voltage of 14.5 V for 30 s.   Tow/Haul Mode (if applicable) Pressing the Tow/Haul Mode button located on the center stack, the vehicle system voltage is raised and the remote (non-vehicle) battery will be charged. Having the headlamps on will raise the system voltage and if the Tow/Haul button is applied it will not serve any purpose. The voltage is regulated between 13.9-14.5 V.      
    • jaszr2
      Active Grille Delete

      By jaszr2 · Posted

      Hello from Australia Just sharing that there is now a way to delete the active shutters entirely with just a plug in module. Opens up tons of room to light bars etc.
    • jake111
      Gasser Subforum Has Been Quiet - - So, Regenerative Braking and Using L10

      By jake111 · Posted

      I have an observation and a question... 1) I watch the voltage closely because I have had to dial in the cut-in/cut-out voltages of the battery separator to my camper.  The "smart" charging drives me nuts.  Anyway, I noticed that when coasting for a while, and especially if lightly using the brakes (though not necessary), the voltage goes up from mid/high-13 volts to mid/high-14 volts.  Then it drops back down after stopping or going again.  Consistently!   The only explanation I can come up with is REGENERATIVE BRAKING!  Well, maybe that's a little bit of an exaggeration, but it's certainly free extra battery charging.   2) Driving on mountain roads I will use L and vary the max gear.  Things straighten out and I end up in L10.  Sometimes I leave it there for a while.  Is there any difference between L10 and D?   

  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...