GM LT-8 6.6 liter Truck Engine. New for 2020.

Originally Posted by A_Harman
The GM truck was so slow, it was causing traffic problems. Even big rigs were pulling out to pass it. The Ford romped up the hill so well, it was a thing of beauty. If you like hearing a V8 sing at 4000+ rpm for 8 minutes, I highly recommend the video that I linked. They actually had to back off early to slow down at the end of the run, otherwise it would have made a better time.
I watched both - the Ford sounded great, like a Mustang with tasteful exhaust. But the Ford also had a 10-speed gearbox and better gearing for towing, the Chevy is still using their older 6-speed. I thought the Chevy was struggling - it could have held it down if the drivetrain was closer to the Ford. And the narrator sounded like Ahnold, just sayin'...
 
Originally Posted by kstanf150
Originally Posted by sw99
I'll take that Ford 7.3L any day of the week.
✅✅✅
GM V8s > Ford V8s. It's been that way as long as most of us have been alive.
 
I'd still take the Ford 6.2 SOHC over either until the kinks have been worked out. Even then, the 6.2 will hold its own just fine, and it looooves to sing at 4,000+RPM.
 
I don't know what they were thinking with a 3.73 and 6 speed, plus the shift algorithm is funky. It wouldn't down shift. It needs more gearing, more gears, and better tuning. In the past when the old 6.0 was tested against the 6.2 or 6.4 with a 6 speed and 4.10's it was close to the 6.2 and always beat the 6.4. Same people tested all of those too. The 6.4 was actually over 2 minutes behind the 6.0 because of gear space in the auto. Ram has that figured out now. I am not sure why they would handicap the truck with a 3.73 and six speed, 16,000 lbs is double what my trailer weights loaded. The new truck is heavier than mine has 401 hp and 464 ft/lbs of torque, my 2017 is 360 and 380, but has 4.10s which makes a huge difference. I hope they put a 10 speed with some 4.10 or 4.30s. You are not buying this type of truck for gas mileage.
 
The Ford has a 4.3 rear end. That was apparent in the conversation at the end of the test. The Chev had a 3.73. Apples and oranges. Here are the gear ratios of the Ford transmission: 4.7 2.99 2.14 1.77 1.52 1.27 1.0 .85 .69 .64 The Chev has the 6 speed The ratios were: 4.06 2.37 1.55 1.16 0.85 0.67 From watching the video, the Ford operates in two gears. I believe the guy said the test was run with gears 2 through 5. The Chev equivalent would have been 2 and 3. So with the two trucks in second gear the Ford would have been at a multiplier 4.3 x 2.99 = 12.9 The Chev would have been 3.73 x 2.37 = 8.8 The gearing differed by (12.9-8.8)/12.9 = 32%. They were testing two sets of drivelines. The engines didn't have much to do with the result. Certainly Chevy could do better. Offering something like a 4.11 would be a start. Please go ahead and see if you can confirm which two gears were being used by the Ford. It was cruising at about 5800 rpm, shifted so it was at 4200 then shifted back down to be at 5800 rpm. Judging from the rpm ratio was the 2 to 3 shift and back to the two. If Chevy made available a 4:11 it would have been a lot more interesting. laugh Edit: It was 4200 and 4800 rpm.
 
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Originally Posted by Snagglefoot
The Ford has a 4.3 rear end. That was apparent in the conversation at the end of the test. The GM had a 3.73. Apples and oranges. Here are the gear ratios of the Ford transmission: 4.7 2.99 2.14 1.77 1.52 1.27 1.0 .85 .64 The Chev has the 6 speed The ratios were: 4.06 2.37 1.55 1.16 0.85 0.67 From watching the video, the Ford operates in two gears. I believe the guy said the test was run with gears 2 through 5. The Chev equivalent would have been 2 and 3. So with the two trucks in second gear the Ford would have been at a multiplier 4.3 x 2.99 = 12.9 The Chev would have been 3.73 x 2.37 = 8.8 The gearing differed by (12.9-8.8)/12.9 = 32%. They were testing two sets of drivelines. The engines didn't have much to do with the result. Certainly Chevy could do better. Offering something like a 4.11 would be a start. Please go ahead and see if you can confirm which two gears were being used by the Ford. It was cruising at about 5800 rpm, shifted so it was at 4200 then shifted back down to be at 5800 rpm.
You read my mind! I was about to look up the transmission ratios, but you beat me to it. The Ford mostly ran in 4th gear during the climb, as is visible on the gauge cluster. After they got the truck up to speed at the beginning, the driver backed off the throttle, and it upshifted for a little while but couldn't maintain speed in 5th, then went back to 4th. Further into the climb, he had it floored, and the 7.3 roared along at 4800 or so for a long time, then lugged down to 4200. At the very end of the run, the hill gets more steep, and the engine lugged down to 4000, then the trans downshifted to 3rd, bringing the engine speed up to 4600. Then they had to back off after a few seconds as they got into traffic at the tunnel entrance. The GM truck didn't have a gear indicator, so it's tough to know what was going on there. The good gear ratio for the Ford was 1.77 x 4.3 = 7.611 The GM didn't have that kind of overall gearing available. In 2nd, it is 8.84, and 3rd is 5.78. The 'tweener gears that Ford's 10-speed has are key. If the GM had dropped to 2nd, the engine would have had to run at 14% higher rpm than the Ford, and would have been buzzing 5400 rpm most of the time. But the driver would have had the option of backing off slightly to maintain a decent speed. If the GM held 3rd gear, the engine would have been running 24% lower rpm, or about 3600 rpm. This is below torque peak rpm of the L8T, and is probably why it fell flat on its face. Transmission programming for heavy vehicles shouldn't allow the engine to drop below torque peak rpm.
 
Good analysis. The likeable old boy had 3000 rpm on the tack. The 6L90 can be manually controlled. He should have dropped it down. I noticed during the early part of the test the rpm was at 5400 rpm. Actually the younger guy asked him to just let the truck decide.
 
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What a joke comparison! . We are going to sit here and compare a one truck with 4.30's to another with 3.73's? Ah ha ha. Where's the bs flag? Shame shame! shrug
 
Originally Posted by P10crew
What a joke comparison! . We are going to sit here and compare a one truck with 4.30's to another with 3.73's? Ah ha ha. Where's the bs flag? Shame shame! shrug
Not so fast there! Look at the gear ratios of the Ford 10-speed that snagglefoot posted. Overall gearing in 4th was 7.61. If the Ford had a 3.73 gear, the trans could have dropped down to 3rd, and the overall gearing would have been 7.98, or about 5% lower. So the truck could have maintained speed with the engine running 5000 rpm. Many closely spaced gears are good!
 
Originally Posted by Dinoburner
Engine capacity, transmission and rear gearing make this test irrelevant.
EXACTLY!
 
Point is Chevy got its south end KICKED as usual when Chevy try's to go head to head with Ford !!!!! Chevy nor GMC can compete !!! There's a reason Ford sells more trucks than any other brand Year after year after year after year after year !!!!!
 
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Couple of things and you know I am GM guy. 1. GM has no 10 speed for this truck...yet 2. GM has no 4.10s for this truck. It is simply not an option...yet (very similar to first years of the 6.0 and 6L90E in the 3/4 ton and up gasser. In 14 all you could get was a 4.10 like my truck. Not sure why they didn't learn from that) 3. So they tested what GM could provide with what Ford could provide. If you want a gasser 3/4 ton and up these are your options minus the new 8 speed 6.4 Hemi Ram 4.On these test they always let the truck decide what gear to be in to keep it sorta fair. They will not manually shift. The test is relevant if you want a gas 3/4 ton or better and don't care about brand. The Ford drug the GM offering. The GM 6.6 needs 4.10s or 4.30s with an 8 or 10 speed. Having said all that no one pulls the Ike daily and if they do at those weights they probably have a diesel. For someone lugging around a 10,000ish lbs or under for work or play. All of the gas 3/4 tons and up are just fine. 16,700 lbs is a lot of trailer. Not many travel trailers weigh that much loaded.
 
Originally Posted by kstanf150
Point is Chevy got its south end KICKED as usual when Chevy try's to go head to head with Ford !!!!! Chevy nor GMC can compete !!! There's a reason Ford sells more trucks than any other brand Year after year after year after year after year !!!!!
Well that wasn't always the case until the 6.2 was offered in the 3/4 ton and up. The 6.0 killed the 5.4 and the 8.1 killed the V-10 it wasn't even a comparison. It did so in both towing and reliability. Edit only time will tell how reliable the new offerings are. As you remember the 6.2 has some pain with rocker arms and valves springs. And just like any other gasser towing exhaust manifolds and bolts have had their problems.
 
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Kstan.. could you edit your post and ad one more year after year? That should guarantee the padlock.
 
I think with real info this would also roll into fuel economy and what folks are really doing with LT's - cost of ownership and all. That kind of load would be managed by a diesel in this part of the world. Our lots are 2 to 1 Super Duty vs 150 - and they are PSD. Most HD gassers I see use the bed and tool boxes - diesels pull goosenecks or fun stuff. It will take 5 years or so to see if the larger displacement gassers were a good idea or not. It's interesting for now - but too soon to tell.
 
Originally Posted by 4WD
I think with real info this would also roll into fuel economy and what folks are really doing with LT's - cost of ownership and all. That kind of load would be managed by a diesel in this part of the world. Our lots are 2 to 1 Super Duty vs 150 - and they are PSD. Most HD gassers I see use the bed and tool boxes - diesels pull goosenecks or fun stuff. It will take 5 years or so to see if the larger displacement gassers were a good idea or not. It's interesting for now - but too soon to tell.
It really just depends for someone like me who doesn't drive the truck daily and tows about 20 times a year anywhere from 6500 to 8000lbs a gasser 3/4 ton and up works fine. My truck is rated at 13,700. It will never see that. 1 ton running gear with a gas engine is fine for me even going over the Rockies. Tons of gassers and half tons at the campgrounds.
 
Originally Posted by P10crew
Kstan.. could you edit your post and ad one more year after year? That should guarantee the padlock.
Maybe like 40+ years of Ford top sales over Chevy ??? That's hard to type over and over and over and over again !!!👍 40 + years Man that's a lot of butt kicking I'd say !!!🤣🤣🤣🤣
 
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One of our local salvage yards used to have a nearly new 4 door single rear wheel truck that looked like it possibly hit an approach with a loaded gooseneck connected. The trailer hitch went 100% all the way through the cab and stopped at the fire wall. 16,700 lbs connected to those trucks is a death wish if you ever have to make an emergency stop. Lots-o- blood in the drivers area.
 
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What ? No King Ranch PSD farm truck with a huge Yellow Fin and 3 x 400 HP Merc Verado's … oh, and the Farm Truck plates to prove it, LoL ...
 
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