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Gm's new 6.6l gas engine

yellowK20 said:
It’s not to small for the 6.0 you just need two of them :)
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So they are pretty good for duals but I have no idea what possessed my buddy to try it.. I thought for sure it was gonna melt the exhaust valves or something from all the heat the hot side generated.
 
sreidmx said:
So we actually tested a single he351cw on a 6.0ls and it managed 400hp and 500lbft to the tire but the back pressure had to be killer.. it died about 3800rpm.

That’s way small for a 6.0 but might be perfect for the 4.8?? Something to try for sure..
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Is the he351cw a factory turbo off of something?
 
tRustyK5 said:
Is the he351cw a factory turbo off of something?
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'04.5-06 Cummins in Dodge/Ram trucks, super small exhaust housing makes them spool fast and they move some good air for a stock turbo. Basically as good as it gets for stock diesel light truck stuff without messing with variable vane turbos (hard to swap).

I have one on the 12V in my CUCV and love it, super cheap (~$200 all over the place) and it's nearly a direct bolt on with a 12V. Just different intercooler plumbing, everything else bolts up. That engine is ~425hp, and more than double that in torque. That's all that little turbo can do, I have more fuel than air even with a 1st gen VE injection pump.

On a 6.0L LQ4/etc, 425 hp is easy with just a cam swap. The little HE351CW isn't up for much more power than that. I have a 69mm turbo on the 6.0L in my Blazer buggy, that project started with the idea of using a diesel turbo but I wisely went a lot larger.
 
vandelay industries said:
i somewhat understand the point about the transmissionses having 8,10,12 gears and have taken that into consideration. i still want to see the torque curves of both the 6.6 and 6.2.

Like a few others, i'm perplexed about the need for this new 6.6 engine, when the 6.2 produces similar peak numbers----at first glance. Again, let's see the torque curves.
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Here is the 14-18 6.2.

The transmission is where the magic really happens. It's always at an optimal RPM. I really like towing with my 2018 Sierra.

This motor fills that gap for those that need more payload than the 1500 offers, but regularly tow 10-12k. I know my half ton has no issues pulling my travel trailer, but I'll run out of payload before I hit my tow limit.

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I thought it was interesting that there was so much talk in this thread about low end torque, concerning an engine with variable valve timing, direct injection and a 10 speed transmission. Aside from general power output, that engine will always be near its peak torque any time it wants.
 
1977k5 said:
I thought it was interesting that there was so much talk in this thread about low end torque, concerning an engine with variable valve timing, direct injection and a 10 speed transmission. Aside from general power output, that engine will always be near its peak torque any time it wants.
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Great point..
 
1977k5 said:
I thought it was interesting that there was so much talk in this thread about low end torque, concerning an engine with variable valve timing, direct injection and a 10 speed transmission. Aside from general power output, that engine will always be near its peak torque any time it wants.
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I'm not familiar with the 10 speed at all, but if it's the lazy type that is always hunting and poking between gears, the engine may not feel responsive at all.
 
Low end torque isn't nearly as important as it used to be, mainly because of 6+ speed transmissions that keep the engine in the peak RPM range and the fact that these new engines can run at 4,000 RPM all day long. Back in the day with the SM465 and 3-speed autos an engine really need low end lugging ability because of the huge gaps between gears.
 
With a heavy load and long grade, with a perfect transmission that 6.2 will be screaming between 4100 and 5600RPM for several minutes at a time. You'll just be going 10 or 15MPH faster than with a 6.0. Some people are bothered by screaming small blocks and willing to pay for the diesel that does it all at modest RPM. It may be mostly perception, but there's a difference between towing performance and towing comfort.
 
All of the reasons why a diesel is better for people who tow heavy, and keep there trucks for long periods. If your 6.6 gas engine has to spin 4500 rpm to do what my diesel can do at 1800 , well it doesn’t take a rocket surgeon to figure out which engine will last longer and have better efficiency .

That fancy 10-spd would be just as good behind a low rpm tourqe monster , a good drive train keeps the engine in its “sweet spot”
 
Blue85 said:
With a heavy load and long grade, with a perfect transmission that 6.2 will be screaming between 4100 and 5600RPM for several minutes at a time. You'll just be going 10 or 15MPH faster than with a 6.0. Some people are bothered by screaming small blocks and willing to pay for the diesel that does it all at modest RPM. It may be mostly perception, but there's a difference between towing performance and towing comfort.
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This isn't true. I rarely hit 4k pulling 8-9k travel trailer over the Cascades and the Rockies. Plenty of 6-8 percent grades. It'll hold 60-65 without very much drama at all. Without traffic slowdowns I can pull Snoqualmie pass around 3100 RPMs. The transmission really does wonders. It's not like a 6.0 with a 6 speed at all.
 
yellowK20 said:
All of the reasons why a diesel is better for people who tow heavy, and keep there trucks for long periods. If your 6.6 gas engine has to spin 4500 rpm to do what my diesel can do at 1800 , well it doesn’t take a rocket surgeon to figure out which engine will last longer and have better efficiency .

That fancy 10-spd would be just as good behind a low rpm tourqe monster , a good drive train keeps the engine in its “sweet spot”
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Blue85 said:
With a heavy load and long grade, with a perfect transmission that 6.2 will be screaming between 4100 and 5600RPM for several minutes at a time. You'll just be going 10 or 15MPH faster than with a 6.0. Some people are bothered by screaming small blocks and willing to pay for the diesel that does it all at modest RPM. It may be mostly perception, but there's a difference between towing performance and towing comfort.
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These are both legitimate comments. A lot of people are scared to death to rev up their engines because they think it will grenade. My 6.0L has spent quite a bit of time running 4,000 rpm up a grade and now has 150k on the odometer with no issues. Now I'm not talking about running 4,000 rpm for 30 miles at a time but usually only for a minute or less while pulling a big grade and not wanting to drop speed any. Will your fuel mileage go down some doing this, sure. However I'm not that worried about engine longevity in the grand scheme of things. Keep in mind that the added "wear" of running higher RPM can be partially offset by not putting as much strain on the engine trying to lug it up a hill. Regarding the comment about the diesel being able to chug along at 1,800 RPM while the gasser has to hit 4,500 RPM.....not real sure about that. My interpretation of the comment is that a gasser is doing multiple downshifts and screaming to pull the hill while a diesel doesn't downshift at all. Yes, the diesel will pull the hill better and with less additional RPM, but I bet it would still kickdown a gear and raise RPM's some in this situation.

I still chuckle at some of the people that drive manual transmissions. Wife had a friend that drove a semi-sporty car with a manual trans for years. It probably redlined at 6,000+RPM but I doubt it ever saw anything above 3,000 RPM. Still remember riding in the car with her as we were getting ready to merge onto a busy freeway. She said "I'm going to have to rev it up pretty high to get up to speed while merging, so don't be startled"......chuckled to myself as she shifted through the gears at 3K. I was driving a 5-speed Toyota Tacoma at the time and don't think I ever shifted BELOW 3,000 RPM.

With that comment out of the way, I have always said there is a legitimate market and need for diesel trucks so don't get me wrong. If somebody told me to pick out any truck I want for free there is a good chance it would be a diesel.....but when I have to pay for that truck there is more thought involved. Yes, diesels have more power and are "better" at towing. If you do a lot of heavy towing I would recommend a diesel at some point, but as mentioned above there is a difference between what can get the job done (gas truck) versus what might tow more "comfortably" in regards to not appearing to stress as much.
 
I'm happy with the LBZ Dmax and Allison 6 speed. Doesn't hunt and pulls what is needed.
I don't understand these light duty trucks receiving higher and higher towing capacities when they are still the same weight.
The numbers war these manufacturers feed us is crazy. Buy a topkick or semi for crying out loud. Maybe the brakes are bigger and drivetrains are badass, but it's still a 10k# truck towing a 30k# trailer.
Just doesn't make sense to me. I'm in shock when I see these trucks with gooseneck trailers fully loaded with cars.
 
x2 on @K85 Octane said for towing specs . how can under 10klbs empty weight be expected to stop 20-30k lbs in major panic stops ? ? ? heck even semi trucks in the high 15-18k lb range have trouble some times .

and all these crazy high hp/tq #'s they keep selling the 98% of the stupid driving world is just going to lead to problems i think . most drivers cant handle the basic sedan car or average suv yet they can go out and buy the 800+hp car/truck/suv and think it will handle the same .

and all these big towing combo's should require you to have a valid cdl lic . but lots of dot and police dont even check to see if there legal drivers for these combo's . although they have started to crack down a bit more these days .

and what about grandpa or computer desk jockey guy with a class A diesel pusher motor home with full air brakes ? ? the most i have heard of is a air brake r/v endorsement on the license . . . yet no full on cdl with the huge trailers they pull behind them and no heath cards per year to pass a dot requirement .

its nice we are getting new stuff and more bad a$$ stuff but at what cost to the average person .
 
sweetk30 said:
and all these big towing combo's should require you to have a valid cdl lic .
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When I first jumped behind the wheel of a class A motorhome it amazed me that it was all legal on standard DL. As for license required for towing, that's a mixed bag since increased regulations and fees aren't welcome. It is ridiculous to see people towing who can't/won't back their trailer. I've seen them drive off from campgrounds all mad because there are no pull-through sites available.

I do overhear people throwing around numbers as though factory tow rating and trailer dry weight are the only 2 things to know. You can have 1,000,000 torques, but exceed your vehicle payload or CVWR way before you hit the tow rating - partly because people carry way more stuff than they think.
 
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