Jump to content

6.6 Gasser

gearheadesw

By gearheadesw
in 6.6L Gas V8 (L8T)

Recommended Posts

gearheadesw Senior Enthusiast

gearheadesw

Posted
Posted

I’m really interested in hearing some reviews on this new engine. Read Newdudes review and it sounds like a great engine and trans even with the 6 speed. Would like to hear from new owners and get some opinions. 

 

And I wanted to be the first post in here, haHa. 

  • Replies 114
  • Created
  • Last Reply
Pastusak.t Enthusiast

Pastusak.t

Posted
Posted

I drove one the other day. It was a LT Silverado. I drive a 16 6.0 gmc sle now and I can say you can definitely feel the extra torque. How that will translate into towing I’m not sure but I could tell a difference. I also notice that the truck over all seemed much more fleshed out, or smoother. On the short drive I took, the transmission shifted extremely smooth and I couldn’t feel any driveline clunk like I get in mine sometimes. (That could be because it’s brand new.) I got on the highway and was doing 85 without realizing it (also no Chevy shake at all). I only drove about 25 miles so I didn’t really get a good sense of the mpg, plus the truck only had 5 miles on it when we left so mpg is probably not that great yet. Overall I was impressed by it. I really want to compare towing with my travel trailer, hoping the 6.6 will out perform my 6.0. I am optimistic and if they throw a 10 speed behind it I’ll trade the 6.0 in pretty quickly.

gearheadesw Senior Enthusiast

gearheadesw

Posted
  • Author
Posted

Also interested in the difference between the 6 speed transmission and the 10 speed. The extra gears may or may not help out the gas engine, the diesels have a lot less rpm to deal with, so I can see them needing it. 

Sunshine39 Enthusiast

Sunshine39

Posted
Posted

I’ve got one with about 600 miles on it.

Hard to compare it to our old 2001 extended cab 1500 minimum truck.

Thus thing is big and roomy compared to it.

taking a little getting used to all the fancy things it has but sure like the HUD and the trailering options.

Pulled our little 31’ trailer today and it didn’t feel it was back there.

Watching the mpg, it looks like it will be close to the 9.8mpg or a tad better than the 2001 did on level ground. This is an SLT 2500HD 2020 about a week old

ApertureX Enthusiast

ApertureX

Posted
Posted
3 hours ago, Sunshine39 said:

Pulled our little 31’ trailer today and it didn’t feel it was back there.

What type of trailer? How much does it weigh?

Sunshine39 Enthusiast

Sunshine39

Posted
Posted
2 hours ago, ApertureX said:

What type of trailer? How much does it weigh?

It’s a travel trailer and only weighs about 6500

pounds.

Pastusak.t Enthusiast

Pastusak.t

Posted
Posted
19 hours ago, Sunshine39 said:

I’ve got one with about 600 miles on it.

Hard to compare it to our old 2001 extended cab 1500 minimum truck.

Thus thing is big and roomy compared to it.

taking a little getting used to all the fancy things it has but sure like the HUD and the trailering options.

Pulled our little 31’ trailer today and it didn’t feel it was back there.

Watching the mpg, it looks like it will be close to the 9.8mpg or a tad better than the 2001 did on level ground. This is an SLT 2500HD 2020 about a week old

Was that 9.8mpg towing your travel trailer? And at what speed do you normally tow if it was. I can get about 8 mpg towing 9000lbs doing about 60-63 mph in a 2016 6.0.  If you can get 9.8 at 70 that’d be a pretty decent boost in fuel economy.

Sunshine39 Enthusiast

Sunshine39

Posted
Posted
9 hours ago, Pastusak.t said:

Was that 9.8mpg towing your travel trailer? And at what speed do you normally tow if it was. I can get about 8 mpg towing 9000lbs doing about 60-63 mph in a 2016 6.0.  If you can get 9.8 at 70 that’d be a pretty decent boost in fuel economy.

I usually tow around 60 or just a little above towing but about 2500 pounds lighter with my trailer. Haven’t tried any faster towing yet.

the old half ton didn’t too good going much faster 

Teach Enthusiast

Teach

Posted
Posted

Placed an order for one today at my local dealer. Gas engine, 2500 crew cab, 4X4, short  .   I was told 8-10 weeks until delivery.   We shall see.   I have owned diesels before, an 01 Dodge 2500 with a Cummins and a 16 Colorado with the 2.8 Duramax.   Just could not justify a $10 K Duramax option on the new Silverrado HD.   To be honest, I hear to many horror stories about the SCR and the particulate filter traps.    I teach Diesel Tech and Automotive so I have an understanding of what is happening.   Even doing the repairs myself the cost would be too high for me. 

bowtie2007 Enthusiast

bowtie2007

Posted
Posted

I also placed my order for a gas 2500 and was told 8 weeks for delivery. My 2019 half ton was not pulling my travel trailer as well as i hoped. The 6.2 never struggled but the suspension bounce and suction from 18 wheelers made me rethink my decision. The trailer is around 7000 lbs so i didn't feel the need to get a diesel for an extra 10k.

Sent from my SM-G892A using Tapatalk

Teach Enthusiast

Teach

Posted
Posted

We currently tow a Passort  153ml travel trailer which weighs in at about 3500 lbs so that swayed my decision on the 6.6 gasser.     Really don’t ever see myself towing anything heavier than 8,000 lbs

CRApex Enthusiast

CRApex

Posted
Posted
4 hours ago, Teach said:

Placed an order for one today at my local dealer. Gas engine, 2500 crew cab, 4X4, short  .   I was told 8-10 weeks until delivery.   We shall see.   I have owned diesels before, an 01 Dodge 2500 with a Cummins and a 16 Colorado with the 2.8 Duramax.   Just could not justify a $10 K Duramax option on the new Silverrado HD.   To be honest, I hear to many horror stories about the SCR and the particulate filter traps.    I teach Diesel Tech and Automotive so I have an understanding of what is happening.   Even doing the repairs myself the cost would be too high for me. 

What horror stories have you heard? I’ve had three, all flawless, maybe i’m Just a lucky one.  Nice part with the Dmax is the 100k warranty.  I should be getting my 20 with the Dmax next week.  I am intrigued by the new 6.6 gas tho, waiting for the 10spd  before i’d Be too interested...

Teach Enthusiast

Teach

Posted
Posted

DEF system failures mostly sensors, plugged up SCR and catalytic plugging.   Soot from EGR contamination wearing out bearings, seals and rings.   People not running them long enough, fast enough to keep the engine at operating temperature.    Have students working the industry who report these failures to me.       Bosch having issues with injector pumps and American diesel fuel on Duramax engines.     Don’t know if it is all true just reporting what I have heard.    Guess it is “buyer beware”.      All this emission equipment has to take some toll on the engine longevity.  I am a big believer in “By-pass” oil filtration and I do not run my trucks without one, more so with a diesel to filter out the carbon particulates from the engine oil.   The new truck will have one installed the first week I own it. ???

Cowpie Senior Enthusiast

Cowpie

Posted
Posted

Actually, even a diesel would benefit from more gears.  The purpose of having more gears is to reduce the engine RPM spread between shifts.  That is why I have an 18 speed in my semi truck.   The top gear ratio of the 8 speed is similar to the 6 speed, and the 10 speed will be no different.  Just like my 18 speed in my semi truck has virtually the same top gear ratio as a 10 speed.  

 

But, given the track record of the 8 speed in the GM 1/2 tons, I would be more inclined to have the 6.6L gasser with the 6 speed.  Even if they decide to go with a 10 speed, I would sit it out for a minimum of 2 years before considering just so they can get all the bugs worked out.   I will be sitting out the 6.6L for at least 2 years for the same reason.  So if while I am sitting out the .6.6 waiting for all the potential problems to get worked out, if they then come out with the 10 speed behind it, that will add an additional 2 years.  I would have preferred they would have come out with both the L8T and the 10 speed at the same time.  

Archived

This topic is now archived and is closed to further replies.

Go to topic listing

  • Latest Articles

  • Posts

    • AidenVorpagel
      cam upgrade in CA

      By AidenVorpagel · Posted

      hello I recently bought a 2012 gmc 1500 with a 5.3 and have a AFM disabler on it I'm interested in doing a cam but I'm worried if I remove the AFM system I will fail smog does anyone have info if they are able to detect that or a work around to it (not talking about hot smogging) please let me know thank you  
    • B14Sierra
      Noise after AFM delete

      By B14Sierra · Posted

      Did you figure it out?
    • B14Sierra
      Possible lifter tick after DOD delete

      By B14Sierra · Posted

      Update. I started chasing down my symptoms. Started first with pulling valve covers and looked at everything. Everything looked good and couldn't hear or feel anything different. Then a compression test. 240 psi or really close on each cylinder. I was worried I was a tooth off of timing. Not bad for an engine with 173,000. Granted I did put new heads on. I sprayed water around the injector area to see if I could hear a change. Nothing. I hooked up my new hp tuner which I should have done in the first place but I don't really know what I'm looking at just yet but am learning. I noticed the fuel trims were way off so that told me I have to have either a bad injector or exhaust leak. New injectors, so I did the shop vac on blower and in the tail pipe. Sprayed soapy water and found the exhaust flange on the drivers side was leaking. I didn't think it would be that considereding I pulled the heads and left the manifolds attached. I did have the transmission replaced not long ago. They must have not seated them properly but I guess I didn't notice. I put in new gaskets on both sides. Which by the way isn't a bad job but I had a hard time getting them to seal right. Took two attempts. Reset the fuel trims and the ticking is gone, engine runs smooth and acceleration has improved. Got to feel the real difference with that stage 1 cam. It's not that big of a difference but it does add a little more. It feels like how the truck should have been from the factory.
    • Grumpy Bear
      Some Assembly is Required

      By Grumpy Bear · Posted

      Can it still be Assembled I?    Stribeck says that we need a certain amount of viscosity under conditions of load and velocity to prevent two surfaces of a know roughness from tearing each other asunder. And we have marketing trying to tell the masses that those two surfaced require less of that commodity due to more exact limits being placed on the same old clearances. We also know that there are limits to how hard something can before it becomes to brittle to be viable and to smooth to 'wet' the surface and that both of those conditions have been known and met since about the Second World War.    That viscosity value shook out at 10 centistokes at 212 F just under a hundred years ago.  Give this a look: [Anton Parr]     What is advertised is the Kinematic viscosity (mm2/s) or that which has been density adjusted but the value we are after is the dynamic viscosity (mPa.s) or true viscosity. You can see that this number is dependent on density thus base stock and temperature. You can also see that an SAE 30 doesn't reach that value in this example. However an SAE 30 that is at the upper end of the SAE 30 range; 12.5 cSt (mm2/s), might. 12.5 * .83 = 10.375 (mm2/s). If you could find an SAE 30 at the upper end these days.   Then there is the complication of viscosity modifiers or VII or VM, whatever you wish to call them. Polymers added to very thin base oils, perhaps 3 to 6 cP oils, that will meet the SAE *W30 spec at 'tested' shear rates and 100 C/212F  target temperature. So a polymer fortified base that is a fraction of the 10 cP requirement Stribeck insist upon.   This could be all well and good if those polymers didn't have two very problematic 'features'. They shear or loose viscosity both 1.) permanently and 2.) temporality. And they do both omitted in the advertised data with the distinct  purpose of deceiving the consumer of the actual operating state of the fluid. I've shown the example of Warren Oils COSTCO 10.91 cSt 5W30 formuation several times where the 100 C HTHS value is 6.9 cP!! That's the temporary shear down and with and SSI or shear stability index of 9.4 cSt. Note the intentional deception in using mixed units?    After a short while that 9.4 cSt oil has a viscosity corrected dynamic value of 7.8 cP. But as the SSI is still within the range of an SAE *W30 whose lower value is 9.3 cSt.    This allows them to continue to call this SAE 16 weight oil a 30 weight, the cake, and still meet the API requirements for fuel efficiency IMPROVEMENT mandated by the EPA. The eating of the cake. By the time you've worn out your motor doing the responsible thing by adhering to the warranty requirements, (the stick), you get deprived of the carrot, wear control. So sad, to bad.   So what can be done? Do I need actually say? [Anton Parr]       Even this must be monitored if the oil is on the low side and the VII an organic or you opt for a 0W40 with an even lighter base oil and more / higher MW VII. (Note the lower density of the 40 weight versus the SAE 30 mono-weight?)    There is another workaround. Temperature. An SAE *W30 run at a bulk temperature of between 180 and 195 F.    Being the belt and suspenders sort I am I do both. Run it cook and run it heavy.    In Part II I'll work the AW package. 
    • Atlas
      Wow I'm in a pickle. (Broke down truck) and a story.

      By Atlas · Posted

      So, do I go elbow-deep on this thing or list it for sale and play dumb? Seems to "runs good."   I'm about $1200 away from having: -a rebuilt injector ($300) -a new cat ($250) -a new cat back exhaust (OE style) ($300) -a new AC compressor ($200) -AC refrigerant charge ($150)   In theory, this should rectify the obvious detracting issues from its value and operability. Cold AC with a non-squeaking AC pulley both sounds and feels good. An exhaust that isn't cut/hacked in 17 different places and doesn't vibrate on a crossmember would make it sound and feel less janky. A working cat would help the stink, and will save the earth, but *if and only if* the fuel system is working properly, which would also address the intermittent "rich" CEL.   Heard a good one... CEL for "Rich condition" means you haven't spent enough money on the truck lately, and it's letting you know.   Rebuilding the injector would seem to be the most important part. Replacing the cat would be secondary. I don't think mine is plugged or overly restricted, but it might be a little restricted? I have no good way to tell other than seat of the pants feel. I hate the smell.   The current theory is I have a rich idle problem: A bad fuel pressure regulator, or a leaking injector(s) being the highest probabilities. I already replaced the FPR but that doesn't mean its replacement isn't also bad. It was a new part from Dorman, but the packaging looked like it had been sitting on a shelf for 20 years.   This is the (single) upstream O2 sensor shown at idle. I'm getting a lot of "rich" it seems. Sometimes it stays high like that and doesn't drop down. That makes me think it's processing injector leaks or a partially stuck open injector.     Other times it looks like this. Nice oscillations between rich and lean, which is what I think it should be. Under load and at speed, the oscillations are nice and tight and uniform looking, high and low.     Fuel trims suggest the PCM is compensating pretty hard at idle to pull fuel out. But it's not enough to trip a CEL. Something about slowing to a stop: brake vaccum booster, EGR, or the EVAP purge is delayed, or there's pooled fuel in the intake again that's draining into a cylinder is enough to set the CEL. Of course, in two days of driving, it hasn't set. I was hoping to actually look at the freeze-frame data when it sets. IAT is high because it's idling on an 83 degree day here.  

  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...