Grumpy Bear's All-Encompassing 2019/2020 GM Truck Hatred Thread

[f8l vnm]

Not a big 4CYL in a truck guy myself but i would take the 2.7 over the 4.3 any day . More power and more torque and better milage. Sound wise , its probably about the same i would say  

[the wanderer]

6 minutes ago, flyingfool said:

more gears is all about emissions improvements not for making power.  

 

Completely incorrect. Your engine has a small range where it is making peak power (say for example, 5500 RPMs). If you have 4 gears in your truck, the second you upshift you drop out of your power band and "whomp", there goes your power.

 

If you have 10 gears, each shift drops you from 5600 to 5200, keeping you right in your peak range. The less gears you have, the more you drop between shifts.

 

Again, go watch this on YouTube, it's explained very easily using charts, math and whiteboards.

[TNTSierra]

9 minutes ago, the wanderer said:

 

Huh? More gears = more opportunity to have the lowest possible RPMs, while still delivering the requested power. If it needs to downshift because it can't maintain enough power in the current gear, then it will downshift to a lesser RPM (with 10 gears) than it would have if there were only 6 or 8 gears. Less gears = higher jumps in RPM.

 

Think in extremes, and it becomes very clear. What is better, a 2 speed gear box, or a CVT? The CVT, because it has infinite gears. Whatever speed you are driving at, whatever power you require at that speed, the CVT will optimize it for you.

 

The 10 speed is closer to "infinite gears" than a 6 or an 8.

 

I suggest you watch "Engineering Explained" on YouTube who has done multiple videos on this. 10 speed all the way brother.

I understand that more gears equals lower rpm. You’re not understanding me. When a smaller engine doesn’t have the HP and especially TQ the larger engine has. It will have to downshift more, causing it to burn more fuel.  If your talking about 2 of the same engines but one with 6 , 8, or 10.  Then of course the 10 will be best.  U obviously didn’t comprehend my previous posts.  

[the wanderer]

1 minute ago, TNTSilverado said:

I understand that more gears equals lower rpm. You’re not understanding me. When a smaller engine doesn’t have the HP and especially TQ the larger engine has. It will have to downshift more, causing it to burn more fuel.  If your talking about 2 of the same engines but one with 6 , 8, or 10.  Then of course the 10 will be best.  U obviously didn’t comprehend my previous posts.  

Read my first post; my claim is that the 4.3 v6 suffers from a poor transmission, and bumping that up to 10 speed would be a "game changer". I'm not comparing two engines, I'm comparing 4.3 with a 6 speed vs a 4.3 with a 10, and how much better that 4.3 would be with a 10 instead.

[TNTSierra]

45 minutes ago, the wanderer said:

 

Don't be so sure about that today; the v8 is running on reduced cylinders quite often, so probably 4 or 6 while on rural/freeway.

 

The biggest issue I have with the 4.3 is typical GM BS; they give you the crummiest transmission available, and leave the 10 speed for the more powerful engines, when in fact, those engines need the 10 gears less than the 4.3 does. Just like they do in the HD world; the gas gets a 6 speed when it really needs 10, and the diesel gets 10 when it can probably work just as well on 6 or 8. Ford and Ram are far better in this respect, and it's one of the reasons why I refused to buy a GMC this time around.

 

Drop the same 10 speed in a truck with the 4.3 and I bet the game changes, fast.

Your first statement was what I was going off of, because you stated that the V8 is running on reduced cylinders. Well my 6.2L just changed over from V4 to V8 or what ever other "V" it was in and its RPM's don't change thus getting better FE because it doesn't have to downshift.  In a smaller engine it would.  I've seen it first hand with both GM v8's and 2 Trailblazer motors.  The TQ just wasn't there to keep it in the cruise speed going up hills or a head wind. 

 

As for the 4.3 with the 10 speed, I agree with you that it would wake it up a bit. I still don't know why GM is lackadaisical when it comes to putting in the 10 spd with their lower trim truck and the new HD 6.6L gasser.  That truck would be a monster with the 10 spd. 

 

My whole argument was that even if the 4.3L got the 10 spd vs a 5.3L with a 10 spd. In the real world the 5.3L wouldn't shift as much going up hills/mountians and facing a head wind like the V6 would.

 

And also, I totally agree with you on Furds. I can't stand them, had one in the family and was total junk, won't go back.  

 

 

[Grumpy Bear]

1 hour ago, the wanderer said:

 

Don't be so sure about that today; the v8 is running on reduced cylinders quite often, so probably 4 or 6 while on rural/freeway.

 

This is a really interesting idea.

 

The 5.3 on AFM or four cylinders is 162 cubic inches.

The 4.3 on AFM or four cylinders is  215 cubic inches.

 

Now you would think that the DFM would be of some help here.

Does it? I don't know. 

 

Here's what I do know. I've never seen nor read of an Ecotec3 5.3 knocking out an average 30.5 mpg for an entire summer but I know of a 4.3 that has. (Pepper 2019 April - September) It will be between 28.5 and 29.5 for this year. Since April 1 I've logged 14,756 miles using 507 gallons of fuel for an average 29.1 mpg at a cost of just under 7 cents a mile. 

 

You let me know whose T1 DMF 5.3 has pulled a single tank at 29 mpg. I'm all ears. In fact I'll take a 4.3 T1's results. 

 

Here's the thing. AFM and DFM are load based and load in this case means torque based. If you have a graph of operation, (look at the PDF I provided) whose bottom scale is rpm and whose vertical scale is torque and assign each a maximum and minimum value you have a BOX. The AFM system actually has three boxes. I expect DFM would be pretty close in operation. The smallest box which gives the highest efficiency and maximum duty cycle has a very VERY low maximum torque value. 

 

The reason Pepper gets such good mileage is that 1.) I am aware of this and work with it, not against it. 2.) I've taken pains to reduce frontal area (lowered) and minimize rolling resistance and internal friction. I can keep it often in the smallest box at 55 mph. Second smallest box at 62 mph and I have no interest in anything higher. 

 

My biggest knock on this T1 platform has to do with the very thing that neuters these strategies.

 

Frontal Area  

 

Could you imagine the fuel efficiency that would be possible with this current DFM motor in a truck whose envelope was no larger than a 68 C-10 but used all other modern tech?

 

                  Wait, they have a truck that size. It's called a Colorado / Canyon.   

                                                                                          

 

Edited August 28, 2020 by Grumpy Bear

[the wanderer]

22 minutes ago, TNTSilverado said:

Your first statement was what I was going off of, because you stated that the V8 is running on reduced cylinders. Well my 6.2L just changed over from V4 to V8 or what ever other "V" it was in and its RPM's don't change thus getting better FE because it doesn't have to downshift.  In a smaller engine it would.  I've seen it first hand with both GM v8's and 2 Trailblazer motors.  The TQ just wasn't there to keep it in the cruise speed going up hills or a head wind. 

 

As for the 4.3 with the 10 speed, I agree with you that it would wake it up a bit. I still don't know why GM is lackadaisical when it comes to putting in the 10 spd with their lower trim truck and the new HD 6.6L gasser.  That truck would be a monster with the 10 spd. 

 

My whole argument was that even if the 4.3L got the 10 spd vs a 5.3L with a 10 spd. In the real world the 5.3L wouldn't shift as much going up hills/mountians and facing a head wind like the V6 would.

 

And also, I totally agree with you on Furds. I can't stand them, had one in the family and was total junk, won't go back.  

 

 

 

Right, so now the 4.3 and the 5.3 are cruising on a rural road at 55 mph. 5.3 is doing it's thing, reduced cylinders. The 4.3 is on 6. Slight hill shows up, the 5.3 scoots back up to 8 cylinders, the 4.3 has to downshift. So yes at that point RPMs are higher than the 5.3, but it's still using only 6 cylinders instead of 8. Less gas there? Who really knows. You're thought is that the 4.3 will use more gas, and possibly so; but if that 4.3 had 10 gears, like the 5.3, the advantage would only swing more and more in favour of the 4.3, because the jump it needs to downshift too, can be as short as possible (which I see you do agree with, so that's great).

 

Already now with a 6 speed (4.3 uses 6, does it not? Maybe it's up to 8 now, I haven't been keeping up to date) there is some debate, which gets better mileage; that debate will only swing further and further in favour of the 4.3 if had another 4 gears to work with. So I do think the 5.3 has more of an advantage due to transmission gears, than it does due to cylinder deactivation.

 

I can add another data point and say that in the Ram with the MDS, it does next to nothing in terms of fuel savings. I've gotten 25 mpg with MDS disabled, and when I do allow it to operate it is barely active, so even the bigger hemi needs to use 8 cylinders the vast majority of the time. Apples to oranges of course, my big horn is probably heavier than the average LT/SLE as well, but still.

 

Anyway, the 4.3 would look far better up against the 5.3 than it does now, if they were both using the 10 speed.

Edited August 28, 2020 by the wanderer

[TNTSierra]

6 minutes ago, the wanderer said:

 

Right, so now the 4.3 and the 5.3 are cruising on a rural road at 55 mph. 5.3 is doing it's thing, reduced cylinders. The 4.3 is on 6. Slight hill shows up, the 5.3 scoots back up to 8 cylinders, the 4.3 has to downshift. So yes at that point RPMs are higher than the 5.3, but it's still using only 6 cylinders instead of 8. Less gas there? Who really knows. You're thought is that the 4.3 will use more gas, and possibly so; but if that 4.3 had 10 gears, like the 5.3, the advantage would only swing more and more in favour of the 4.3, because the jump it needs to downshift too, can be as short as possible (which I see you do agree with, so that's great).

 

Already now with a 6 speed (4.3 uses 6, does it not? Maybe it's up to 8 now, I haven't been keeping up to date) there is some debate, which gets better mileage; that debate will only swing further and further in favour of the 4.3 if had another 4 gears to work with. So I do think the 5.3 has more of an advantage due to transmission gears, than it does due to cylinder deactivation.

 

I can add another data point and say that in the Ram with the MDS, it does next to nothing in terms of fuel savings. I've gotten 25 mpg with MDS disabled, and when I do allow it to operate it is barely active, so even the bigger hemi needs to use 8 cylinders the vast majority of the time. Apples to oranges of course, my big horn is probably heavier than the average LT/SLE as well, but still.

 

Anyway, the 4.3 would look far better up against the 5.3, if they were both using the 10 speed.

Totally agree with you on this. 4.3l needs the 10 spd. And I would LOVE to test OUR theories on this. But sadly GM I heard is getting rid of the 4.3L. If they would nut up. They should drop it into the Colorado/Canyon. Perfect HP/TQ starting point for that platform. 
Thanks for having a great conversation without being a total douche-bag like another person on this forum. Take care! Have a great weekend. 

Edited August 28, 2020 by TNTSilverado

[Grumpy Bear]

My 4.3 6 speed truck rarely downshifts at 55-65 mph on anything less than a 7% grade.

If fact when it does on a 7% grade it will pull like a draft horse for a half mile before it kicks back. 

I'm mean so rare it's like pulling hens teeth.

 

And even if it did. So what. 

It is what a transmission is for.

You don't get brownie points for a lack of shift.

 

 

 

[the wanderer]

16 minutes ago, Grumpy Bear said:

This is a really interesting idea.

 

The 5.3 on AFM or four cylinders is 162 cubic inches.

The 4.3 on AFM or four cylinders is  215 cubic inches.

 

Now you would think that the DFM would be of some help here.

Does it? I don't know. 

 

Here's what I do know. I've never seen nor read of an Ecotec3 5.3 knocking out an average 30.5 mpg for an entire summer but I know of a 4.3 that has. (Pepper 2019 April - September) It will be between 28.5 and 29.5 for this year. Since April 1 I've logged 14,756 miles using 507 gallons of fuel for an average 29.1 mpg at a cost of just under 7 cents a mile. 

 

You let me know whose T1 DMF 5.3 has pulled a single tank at 29 mpg. I'm all ears. In fact I'll take a 4.3 T1's results. 

 

Here's the thing. AFM and DFM are load based and load in this case means torque based. If you have a graph of operation, (look at the PDF I provided) whose bottom scale is rpm and whose vertical scale is torque and assign each a maximum and minimum value you have a BOX. The AFM system actually has three boxes. I expect DFM would be pretty close in operation. The smallest box which gives the highest efficiency and maximum duty cycle has a very VERY low maximum torque value. 

 

The reason Pepper gets such good mileage is that 1.) I am aware of this and work with it, not against it. 2.) I've taken pains to reduce frontal area (lowered) and minimize rolling resistance and internal friction. I can keep it often in the smallest box at 55 mph. Second smallest box at 62 mph and I have no interest in anything higher. 

 

My biggest knock on this T1 platform has to do with the very thing that neuters these strategies.

 

Frontal Area  

 

Could you imagine the fuel efficiency that would be possible with this current DFM motor in a truck whose envelope was no larger than a 68 C-10 but used all other modern tech?

 

                  Wait, they have a truck that size. It's called a Colorado / Canyon.   

                                                                                          

 

 

But to be fair, you admit to doing various hypermiling techniques, so a fair test would be you with your same techniques/driving style/truck weight in a 5.3. (because you also have a really basic truck, average 2019 is going to be probably couple hundred pounds heavier than yours). Can't really compare your mpg vs other users. There was one user on this forum a year ago ("wiggle-something-or-other" was his id) when I was about to buy one, who claimed he got 27 mpg in the new 2019's with a 5.3/8 speed. I doubt it, but who knows.

Edited August 28, 2020 by the wanderer

[Grumpy Bear]

57 minutes ago, f8l vnm said:

Not a big 4CYL in a truck guy myself but i would take the 2.7 over the 4.3 any day . More power and more torque and better milage. Sound wise , its probably about the same i would say  

I might even consider the 2.7 if it were not for the fact that the cooling and oiling systems are NASA complicated which means trouble. Someone laughed at my roll up windows. Ya know I never replaced a manual window regulator/motor!  

 

Only thing in the T1 that interest me is the 3.Oh, 

[the wanderer]

The 2.7 is a fascinating motor. I don't know whether to love it or run from it, just not been around long enough. But yeah, if the longevity holds out, that might be my next truck. Apparently it's supposed to be just as strong as modern "light diesels", and they designed/tuned it for truck duty right from the start. It is very close 0-60 to the 5.3, but passing power is not as good there due to turbo needing to spool up.

[OnTheReel]

Add two holes to the 2.7, make 450+hp and I’d be in for it as a 6.2 substitute. Butter smooth turbo straight 6, it would be the BMW of the truck world. You know there’s room under the hood since they put the D-Max 6 in.
 

Don’t care about complication, owning any modern vehicle out of warranty is of no interest to me.

[Grumpy Bear]

4 minutes ago, the wanderer said:

 

But to be fair, you admit to doing various hypermiling techniques, so a fair test would be you with your same techniques/driving style/truck weight in a 5.3. (because you also have a really basic truck, average 2019 is going to be probably couple hundred pounds heavier than yours). Can't really compare your mpg vs other users. There was one user on this forum a year ago ("wiggle-something-or-other" was his id) when I was about to buy one, who claimed he got 27 mpg in the new 2019's with a 5.3/8 speed. I doubt it, but who knows.

I admit to no such thing. I live in cruise control. I run a bit under the speed limit most of the time but I employ no hypermilling techniques. I just drive it. No punch and glide. NO dead sticking. Just drive. 

 

Yea, I can and I do BECAUSE it is that very difference that is killing the T1 line up. That IS the argument. 

The T1 can not compete because of it's difference.  It's why I won't buy one. 

 

And actually one of the selling points of the T1 is reduced weight. About 500 pounds if I remember correctly. That would put a factory fresh T1 CC about on even footing with Peppers bloated overweight. Shes carrying 500 lbs of accessories around. Scales 5060 instead of the factory 4521. 

 

 

 

[Grumpy Bear]

I haven't done anything to Pepper anyone else couldn't do with equal means. But there are things I've done to Pepper than just won't work on a T1 because:

 

1.) Frontal area

2.) Locked out PCM/TCM

3.) Vastly more complicated.

4.) Lack of current supplies and parts. 

 

Give it a few years and maybe I'll look at a 3.Oh.