Liking the 6.6 gas

MTU Alum · March 6, 2020

5 hours ago, bshort said:

GM really missed the mark on this application with the displacement and transmission when ford has the 7.3 and a 10 speed. 4.30 rear also available on the

6.6 DI vs 7.3 port injection is not an apple to apple compare. DI makes considerable more power than a similar displaced port injection. Gm estimates DI equals about 0.75 liters of displacement over port injection.

I would argue that the value of the 4.30 decreases considerably once you have a 10 speed automatic. You are going to shift a little less but burn more fuel during normal cruising.

#iworkforGM

Carolina · March 7, 2020

10 hours ago, bshort said:

GM really missed the mark on this application with the displacement and transmission when ford has the 7.3 and a 10 speed. 4.30 rear also available on the Ford.

Not really

bshort · March 7, 2020

16 hours ago, MTU Alum said:

6.6 DI vs 7.3 port injection is not an apple to apple compare. DI makes considerable more power than a similar displaced port injection. Gm estimates DI equals about 0.75 liters of displacement over port injection.

I would argue that the value of the 4.30 decreases considerably once you have a 10 speed automatic. You are going to shift a little less but burn more fuel during normal cruising.

#iworkforGM

At least Ford offers the options of 331, 355, 373 or 430. You can make a grocery hauler for the best mileage or a towing beast. Gm really needs to step up with the ability to customize.

bshort · March 7, 2020

11 hours ago, Carolina said:

Not really

Not really, just somewhat?

Carolina · March 7, 2020

7 hours ago, bshort said:

Not really, just somewhat?

The 6.6 is the base model just as Ford has a base model . Ford has 3 engine options. Gm has 2 . The GM big block capability is yet to be seen. The 6.6 is completely capable of its rating

bshort · March 8, 2020

16 hours ago, Carolina said:

The 6.6 is the base model just as Ford has a base model . Ford has 3 engine options. Gm has 2 . The GM big block capability is yet to be seen. The 6.6 is completely capable of its rating

GM had the ability to do something great and what do they do? Add stroke, DI and call it a day. Couple that to the antiquated 6 speed with a 3.73. Sure, it's capable, but could've been (and still could be) much more.

SierraHD17 · March 8, 2020

31 minutes ago, bshort said:

GM had the ability to do something great and what do they do? Add stroke, DI and call it a day. Couple that to the antiquated 6 speed with a 3.73. Sure, it's capable, but could've been (and still could be) much more.

Its Gm... they are always so far behind they think they are ahead. Wait until they add the 10 speed.. best and only rear gear at that point will be 3.42 lol.

Carolina · March 9, 2020

14 hours ago, bshort said:

GM had the ability to do something great and what do they do? Add stroke, DI and call it a day. Couple that to the antiquated 6 speed with a 3.73. Sure, it's capable, but could've been (and still could be) much more.

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 vehicles for capability , reliability and cost of ownership. The 6.6 has a 15-20 percent efficiency increase over the 6.0 . It has as much torque at barely over idle as it which translates into better towing and drive ability performance. Behind the wheel of one it feels very powerful and is a pleasure to tow with. Of course it doesn’t have a turbo like a diesel and if it did it would be challenge to drive . The 7.3 with the 4:30 gear won’t match the efficiency of the 6.0 much less the 6.6 . Most fleet buyers buy the gas version and historically consumers buy the diesel but that’s changing and all it takes is getting in one . The stigma of you gotta have a diesel is dying because it’s BS. Ford gave it there best shot . Gm is just getting started with this . They can add gear selections, transmissions and bring out a big block . What you see now with Ford is all it will be for years to come with the 7.3 . Either way none of it matters to me . I have a truck that I feel more confident in than in my Diesel with the same efficiency with lower cost fuel. It pulls my stuff without a sweat and when I upgrade my fleet vehicles I won’t think twice about getting the 6.6. No missed marks here I’m delighted with it .

Edited March 9, 2020 by Carolina

SierraHD17 · March 9, 2020

And that's why Ford continues to offer the 6.2 as they have for years... fleet buyers. You just have the option to get a gas that's set up very well to pull with and isn't a headache like any emission laden diesel is...Will GM offer more options in the future? Maybe... they do like to take years to play catch up all the time.

Edited March 9, 2020 by SierraHD17

bshort · March 9, 2020

9 hours ago, Carolina said:

Gm is just getting started with this . They can add gear selections, transmissions and bring out a big block .

They probably should, as the lack of innovation, choices, etc are driving buyers away. Gm is like a soup kitchen.....get in line and get what we give you...and like it. Glad you're happy with what you have.

bshort · March 9, 2020

29 minutes ago, SierraHD17 said:

And that's why Ford continues to offer the 6.2 as they have for years... fleet buyers. You just have the option to get a gas that's set up very well to pull with and isn't a headache like any emission laden diesel is...Will GM offer more options in the future? Maybe... they do like to take years to play catch up all the time.

GM fleet operators would love to continue on with the 6.0 as an option.

mookdoc6 · March 9, 2020

26 minutes ago, bshort said:

GM fleet operators would love to continue on with the 6.0 as an option.

Honestly, they probably would as well for 20yrs "Fleet" owners had a platform that basically required....gas,oil,brakes etc. Sure the tailgate handle ripped off after 2yrs but they NEVER required anything other than gas,oil,brakes! Something FERD has not figured out yet because, Well they are building yet again another engine platform "KUDOS" FERD great another innovative platform for your customers!

SierraHD17 · March 9, 2020

30 minutes ago, bshort said:

GM fleet operators would love to continue on with the 6.0 as an option.

Maybe... the 6.6 if trouble free like it should be will do them just fine and I doubt they will really care.

Carolina · March 16, 2020

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 amazed in the mountains. One thing I noticed is that it tows better on grades at speeds 65-75 vs trying to run 60 due to gear ratios in the transmission . With my setup at least with the 34+ tires . The first grade I hit running 61. It took about 2 miles to drop to 56 at 3200 rpms and I finally floored it to find it wouldn’t downshift further at first ( noticed the same with my 6.0’s ) so I double pumped it and it downshift to 5k , it immediately picked up speed and once it got to 61 5500 I backed off to try and hold the gear but it up shifted to 3500 and it continued to pick up speed no problem with the grade not letting up . It got to 71 and I just backed off more because speed limit was 65. I was less than half way into it on the initial climb and must have let it drop too much to recover . The 2 7% I hit at 66 mph and it carried the speed the entire way running 3700 rpm. On the way back I played around a little and drove 70-75 as the trucks stability wasn’t changed and wasn’t concerned about fuel as much . I hit one and made it downshift to 4K and it didn’t give a crap about the hill at that rpm . It accelerated me effortlessly past a car in the fast lane quick enough to get over before I got stuck behind a 35 mph semi . I pull those same grades 75% of the time when I rv and can’t tell you how many times that’s been but it put a spanking on my 09 duramax on those grades . I can only maintain 58 on the 2 longer ones nearly floored and if I ever tried to floor it to hold low 60’s it has always got to hot for me , transmission and motor . Ive never been able to get into the 70’s with it there . My 6.0‘S stay in the 4000-6000 rpm on those grades and usually drop to 56 floored with nothing left . Once I hit it running 75 and was able to keep 70 staying over 5000 the whole way up with my 6.0 and have tried to do it again and haven’t . But the 6.0’s never got even close to overheating and have had no mechanical issues . Downhill performance was a definite improvement over my 6.0 ‘s also . Not much difference from my duramax without an exhaust brake. When I slowed to 49 on a brake application and it downshifted the second time it eventually dropped to 44 on the 7% and I had to give it the gas to pick speed up before getting in the way . Fuel mileage was 7.8 -8.2 -9.5 . The only place where I can definitely say that my duramax was more pleasant was on the way back in the rolling hills running cruise it would go from 6th -5th after 2 mph drop then from 5th-4th at 4 mph drop . Afterwards it would climb back up to the speed I had it set at (70) . With my foot it was in 5th mostly with some drops to 4th when anticipated the hills and gave it enough pedal to downshift on purpose . I eventually selected manual 5 and set the cruise back and it would just drop 2 mph then recover . The hills were 5- 6% . My duramax tow mode automatically locks out 6th and will downshift on the same hills but it’s less noticeable because the nature of the diesel limited rpm range so 500 vs 1000 rpm increase . Overall i can clearly say it’s the most pleasurable tow I have had with any of my trucks ever . 50 miles into it I would have never thought it would be but after getting the feel for how it tows over a broad range I’m certain. In the backroads it was a cakewalk running 40-50 climbing much steeper grades . I know a l5p would do better but it still amazes me how it compared to my tuned LMM

Edited March 16, 2020 by Carolina

ShotgunZ71 · March 16, 2020

7 hours ago, Carolina said:

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 amazed in the mountains. One thing I noticed is that it tows better on grades at speeds 65-75 vs trying to run 60 due to gear ratios in the transmission . With my setup at least with the 34+ tires . The first grade I hit running 61. It took about 2 miles to drop to 56 at 3200 rpms and I finally floored it to find it wouldn’t downshift further at first ( noticed the same with my 6.0’s ) so I double pumped it and it downshift to 5k , it immediately picked up speed and once it got to 61 5500 I backed off to try and hold the gear but it up shifted to 3500 and it continued to pick up speed no problem with the grade not letting up . It got to 71 and I just backed off more because speed limit was 65. I was less than half way into it on the initial climb and must have let it drop too much to recover . The 2 7% I hit at 66 mph and it carried the speed the entire way running 3700 rpm. On the way back I played around a little and drove 70-75 as the trucks stability wasn’t changed and wasn’t concerned about fuel as much . I hit one and made it downshift to 4K and it didn’t give a crap about the hill at that rpm . It accelerated me effortlessly past a car in the fast lane quick enough to get over before I got stuck behind a 35 mph semi . I pull those same grades 75% of the time when I rv and can’t tell you how many times that’s been but it put a spanking on my 09 duramax on those grades . I can only maintain 58 on the 2 longer ones nearly floored and if I ever tried to floor it to hold low 60’s it has always got to hot for me , transmission and motor . Ive never been able to get into the 70’s with it there . My 6.0‘S stay in the 4000-6000 rpm on those grades and usually drop to 56 floored with nothing left . Once I hit it running 75 and was able to keep 70 staying over 5000 the whole way up with my 6.0 and have tried to do it again and haven’t . But the 6.0’s never got even close to overheating and have had no mechanical issues . Downhill performance was a definite improvement over my 6.0 ‘s also . Not much difference from my duramax without an exhaust brake. When I slowed to 49 on a brake application and it downshifted the second time it eventually dropped to 44 on the 7% and I had to give it the gas to pick speed up before getting in the way . Fuel mileage was 7.8 -8.2 -9.5 . The only place where I can definitely say that my duramax was more pleasant was on the way back in the rolling hills running cruise it would go from 6th -5th after 2 mph drop then from 5th-4th at 4 mph drop . Afterwards it would climb back up to the speed I had it set at (70) . With my foot it was in 5th mostly with some drops to 4th when anticipated the hills and gave it enough pedal to downshift on purpose . I eventually selected manual 5 and set the cruise back and it would just drop 2 mph then recover . The hills were 5- 6% . My duramax tow mode automatically locks out 6th and will downshift on the same hills but it’s less noticeable because the nature of the diesel limited rpm range so 500 vs 1000 rpm increase . Overall i can clearly say it’s the most pleasurable tow I have had with any of my trucks ever . 50 miles into it I would have never thought it would be but after getting the feel for how it tows over a broad range I’m certain. In the backroads it was a cakewalk running 40-50 climbing much steeper grades . I know a l5p would do better but it still amazes me how it compared to my tuned LMM

Thanks for the review on towing in the mountains. I've had my 5th wheel in some rolling hills so far, but not the mountains with my 6.6 gasser. I, too, noticed if you stay above 3000-3500 it will keep speed without slowing down and then having to play catch up. Sometimes I'd lock out 5th and 6th so that the RPM would be elevated. At 70 mph in 4th I am at 3000 and in 3rd it is around 4000. Your fuel mileage was pretty decent, too.