6.6 Gasser Towing

wowens79 · December 4, 2019

Does anyone have any feedback on how the new gasser is towing? In the MPG thread I saw some comments on MPG towing, but I'd like to know how well it tows.

I'm wondering how it will compare to what I'm towing with now, as I feel I need a little more power.

Currently I'm pulling a 33ft, 8000lb travel trailer with a 2002 Chevy 1500HD with the 6.0, and 3.73 gears with a 4spd trans. It struggles in the mountains of North Georgia and Tennesee. Also even when we go to Florida it is basically flat, and it will not hold 65-70mph in 4th, and so I have to tow in 3rd at 3000 rpms.

Curious what gear and rpms it pulls towing on the interstate.

Thanks

dieselfan1 · December 4, 2019

I don't own one but have been paying attention to the chatter on these new motors.

Well for starters it has 100 more h.p. and 100 more ft.lbs. tq. than your 6.0

That alone should say a lot.

I had the same truck you have when it was new and I can tell you this my 2018 5.3 will out do anything that 6.0 did. Especially at the

If I had to tow heavy and didn't want to drop the extra 10g for the dmax I would be all over one of those new 6.6 gassers in a heartbeat. It's a solid motor.

Edited December 4, 2019 by dieselfan1

greatmizzou · December 5, 2019

The transmission will be light years ahead of yours.

that 1500HD is a durable platform tho

wowens79 · December 5, 2019

The ol 1500HD, has been great, I bought it new in 2002, and it's got 238,000 miles on it. No internal engine or tranny work the whole time, just fuel pump, water pump type stuff.

I figure its its about time for a new one, so trying to make sure I get what I want since I keep them for awhile.

SilveradoX2 · December 5, 2019

I use The Fast Lane Truck guys all the time for reviews:

Watch "How Efficient Is the New Chevy Silverado HD Gasser? Hint: There’s a HUGE Difference Towing & Not!" on YouTube

https://youtu.be/vgniroEQ-Us

dieselfan1 · December 5, 2019

2 hours ago, SilveradoX2 said:

I use The Fast Lane Truck guys all the time for reviews:

Watch "How Efficient Is the New Chevy Silverado HD Gasser? Hint: There’s a HUGE Difference Towing & Not!" on YouTube

https://youtu.be/vgniroEQ-Us

That's a 16,000 lb trailer.

The OP has a 8000 lb trailer. He never said he was concerned with MPG.

The 6.6 gas will handle that no problem. Sure it's going to get 8- 9 MPG but the power is there for a 4 ton trailer. Not 8.

BTW I take FLT with a grain of salt like a lot of guys on here.

The Ike test with the same truck and trailer was a joke. Downshift the damn thing.

Edited December 5, 2019 by dieselfan1

Ray Pickle · December 23, 2019

I am going from Cincinnati to Gatlinburg and back pulling my 11600 lb 5th wheel on the 27th. I will report my m.p.g. and impressions when I return. My last truck was 2016 2500 h.d. for comparison.

Ray Pickle · January 1, 2020

Returned today from Gatlinburg, a little over 300 miles each way. Cruised at 62 mph with occasional downhills to 70 mph never ower on hills than 58 mph. The DIC showed 9.1 mpg on trip down. I used tow/ haul most of the way down but not entirely. Same with cruise control. In bigger hills, southern Ky. and Jellico Tn. no cruise. On return trip average 63 mph very little cruise usage. Averaged 9.3 according to DIC. A couple of observations: in tow haul mode in stays in 5th gear longer even on level or slight downhill under 68 mph as a result I drove a lot with tow haul off during flat and downhill on return trip. This truck will maintain speed on level and slight uphill, 1 percent grade in 6th gear. It does so better than previous 16' sbcc gasser. Personally I think a rear gearset around 3.90 would be a perfect compromise between towing performance and mpg. Towing mpg is approx. .5 mpg better than the average of my old trucks trips to same location. Unloaded mpg is about 1.5 mpg better combined.

i82much · January 2, 2020

1 hour ago, Ray Pickle said:

Returned today from Gatlinburg, a little over 300 miles each way. Cruised at 62 mph with occasional downhills to 70 mph never ower on hills than 58 mph. The DIC showed 9.1 mpg on trip down. I used tow/ haul most of the way down but not entirely. Same with cruise control. In bigger hills, southern Ky. and Jellico Tn. no cruise. On return trip average 63 mph very little cruise usage. Averaged 9.3 according to DIC. A couple of observations: in tow haul mode in stays in 5th gear longer even on level or slight downhill under 68 mph as a result I drove a lot with tow haul off during flat and downhill on return trip. This truck will maintain speed on level and slight uphill, 1 percent grade in 6th gear. It does so better than previous 16' sbcc gasser. Personally I think a rear gearset around 3.90 would be a perfect compromise between towing performance and mpg. Towing mpg is approx. .5 mpg better than the average of my old trucks trips to same location. Unloaded mpg is about 1.5 mpg better combined.

thanks for the report! great info.

ShotgunZ71 · January 2, 2020

That's good fuel mileage for that tow. I just returned from a 250 miles trip and averaged 7.6 mpg pulling the 14,300 lb 5er. Most of that was rolling hills and interstate where I kept cruise at 70 when I could. When it go too hilly, I locked out 5 and 6 and let the engine turn a bit more ,so it wouldn't be downshifting, then playing catch up too bad. That may have actually helped the fuel mileage some, in reality. At 70 mph, in 4th gear is 3000 RPM and 3rd gear is 4000 RPM. In 5th at 70, it's around 2300 RPM. Maintained speed very well up and down the hills like that.

Ray Pickle · January 3, 2020

Sound like biggest difference between our numbers are due to weight differences and towed speed differences. More speed than weight. Your mpg sounds just about right.

SkidooSteve12 · January 3, 2020

What size tires are on your 2020 HD compared to your 2016 HD? I have the 20" wheels on my 6.6L gasser and think the 275/65R20 tires have dropped my MPG lower than others with 17" or 18" wheels and tire combo. I've pretty much been babying the truck, sticking to the speed limit at 70 mph, and I'm just below 13 mpg overall average. I know my short commutes don't help and I would see around 14-15 mpg hand calculated if I ran longer highway trips at 70 mph empty. I should be pulling my snowmobile trailer pretty soon, if we ever get some consistent snow in lower Michigan.

On 12/22/2019 at 9:30 PM, Ray Pickle said:

I am going from Cincinnati to Gatlinburg and back pulling my 11600 lb 5th wheel on the 27th. I will report my m.p.g. and impressions when I return. My last truck was 2016 2500 h.d. for comparison.

On 1/1/2020 at 6:57 PM, Ray Pickle said:

Returned today from Gatlinburg, a little over 300 miles each way. Cruised at 62 mph with occasional downhills to 70 mph never ower on hills than 58 mph. The DIC showed 9.1 mpg on trip down. I used tow/ haul most of the way down but not entirely. Same with cruise control. In bigger hills, southern Ky. and Jellico Tn. no cruise. On return trip average 63 mph very little cruise usage. Averaged 9.3 according to DIC. A couple of observations: in tow haul mode in stays in 5th gear longer even on level or slight downhill under 68 mph as a result I drove a lot with tow haul off during flat and downhill on return trip. This truck will maintain speed on level and slight uphill, 1 percent grade in 6th gear. It does so better than previous 16' sbcc gasser. Personally I think a rear gearset around 3.90 would be a perfect compromise between towing performance and mpg. Towing mpg is approx. .5 mpg better than the average of my old trucks trips to same location. Unloaded mpg is about 1.5 mpg better combined.

MTU Alum · January 3, 2020

12 to 13 mpg for typical city/combined driving is pretty typical especially in the winter.

6 to 9 mpg towing depending on weight and drag.

11 to 12 mpg in city

16 mpg highway

These are the numbers I feel are pretty typical from my experience.

#iworkforGM

Ray Pickle · January 3, 2020

Agree with MTU alum on gas mileage estimates. My old truck had 17" the new truck has 20". I believe it has a negative effect on loaded effeciency due to taller tire slightly reducing final gear ratio. But I dont believe it hurts unloaded fuel economy. I achieved around 16.5 mpg unloaded in the rain on a trip to Nashville and back. I think I could have attained slightly over 17 if it was dry.

SkidooSteve12 · January 3, 2020

Yeah I agree too those are realistic MPG numbers that I have seen and expect with a 3/4 ton gasser truck. I'm going to have to see if my MPG changes with my foot a little heavier on the Go pedal. haha