5.3 with 3;42 has higher tow rating than 6.2 with 3:42???

[Badass69]

Unless I am mistaken the 9.5" and 9.76" share the same physical housing.... so actual weight difference of the diff is negligible.

 

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[fondupot]

While it is strange that the 6.2 has less max towing. 100 lbs difference isnt really a big deal.

[2014big3]

This is strange to me the 5.3 has a 100 lb higher tow rating with 3:42 than the 6.2 with 3:42.

I realize the 6.2 truck is a little heavier because of the different rear axle but still

with the big difference in power I would think there would be a bigger difference

in favor of the 6.2.

What do you guys think?

Hi Seamonster

 

I've read the responses to your question and some of them are just nonsense ie exhaust tubing weight or motor weight ( the same BTW) . Just as much nonsense as the GM ratings. A 6.2 will out tow a 5.3 with either a 3.42 or 3.73. The Max Tow pkg ( 3.73 ) does have a slightly bigger axle but you asked about 3.42 vs 3.42. For the record a Z 71 is not available with Max Tow and or 3.73. Here's the what you need to know. GM wants to discourage you from ordering a 6.2 for CAFE ( corporate average fuel economy) reasons so they low ball the 6.2 ratings vs 5.3 for both gear ratio's. There is a small other adjustment to consider in the fine print and that is the ratings are based on the lowest trim level available or no options for that motor and a T.T package. Thus a bare bones 5.3 weights less than any 6.2. All 6.2 are LTZ or SLT and above whereas a 5.3 can come as an LS.

 

Here's the real life and mathematical answer. Assume 3.42 ratio , 55 mph, in 4 th gear (1.53:1) which is 3000 rpm ( a typical towing scenario) In this scenario a 6.2 is making 240hp ( 3000 rpm X 420lbs/ft / 5250 ) the 5.3 makes only 200hp ( 3000 rpm X 350lbs/ft /5250 ) As you can see GM has low balled the 6.2 rating. Same frame, axle , transmission but significantly stronger motor.

 

FYI the numbers for a 3.73 ratio at 55 mph at now 3300 rpm are 6.2 = 270 hp 5.3 = 225 hp thus a 6.2 with 3.42 actually makes more power than 5.3 with a 3.73 . Remember however Max Tow Pkg has the slightly bigger axle and heavier springs and perhaps larger brakes. So perhaps a 5.3 Max Tow and 3.73 would be a little more stable and safer than a 6.2 with 3.42 but the ability to pull would be less than the 6.2.

[Johnnyee]

Hi Seamonster

 

I've read the responses to your question and some of them are just nonsense ie exhaust tubing weight or motor weight ( the same BTW) . Just as much nonsense as the GM ratings. A 6.2 will out tow a 5.3 with either a 3.42 or 3.73. The Max Tow pkg ( 3.73 ) does have a slightly bigger axle but you asked about 3.42 vs 3.42. For the record a Z 71 is not available with Max Tow and or 3.73. Here's the what you need to know. GM wants to discourage you from ordering a 6.2 for CAFE ( corporate average fuel economy) reasons so they low ball the 6.2 ratings vs 5.3 for both gear ratio's. There is a small other adjustment to consider in the fine print and that is the ratings are based on the lowest trim level available or no options for that motor and a T.T package. Thus a bare bones 5.3 weights less than any 6.2. All 6.2 are LTZ or SLT and above whereas a 5.3 can come as an LS.

 

Here's the real life and mathematical answer. Assume 3.42 ratio , 55 mph, in 4 th gear (1.53:1) which is 3000 rpm ( a typical towing scenario) In this scenario a 6.2 is making 240hp ( 3000 rpm X 420lbs/ft / 5250 ) the 5.3 makes only 200hp ( 3000 rpm X 350lbs/ft /5250 ) As you can see GM has low balled the 6.2 rating. Same frame, axle , transmission but significantly stronger motor.

 

FYI the numbers for a 3.73 ratio at 55 mph at now 3300 rpm are 6.2 = 270 hp 5.3 = 225 hp thus a 6.2 with 3.42 actually makes more power than 5.3 with a 3.73 . Remember however Max Tow Pkg has the slightly bigger axle and heavier springs and perhaps larger brakes. So perhaps a 5.3 Max Tow and 3.73 would be a little more stable and safer than a 6.2 with 3.42 but the ability to pull would be less than the 6.2.

2014Big3,

 

I have a question. Based upon the information above, do you have a feeling on how the two vehicles (6.2L/3.73 vs 5.3L/3.73) would compare on fuel consumption if both were pulling a 6,000 lb trailer, at say 60 mph.? The 6.2l uses more fuel unloaded, but if both were loaded equally, the 6.2l would not have to work as hard. Would that have any impact, and what kind of numbers could one expect? Thanks in advance for any insight.

 

Johnny

[Cap'n Pete]

Agreed - the 6.2L will physically out-pull the 5.3L - it's a no brainer.

 

The engine blocks are basically identical, and I'd be willing to bet they run the same exhaust (unless someone can say for certain that the 6.2L runs bigger pipes? ... but I doubt it).

 

Big3 probably hit the nail on the head, that the tow rating probably factors in the truck weight, which is likely higher in the 6.2L trim levels.

[EX-F150 owner]

Same block I think. Power has little to do with it I'd bet. It's all weight. Between the beefier axle and related stuff, a 6.2 truck is probably ~100lbs heavier so that has to come out of the capacity.

But if it is beefier and has more power this just doesn't make sense. If it is all that it should be rated for more, not less

[MikeNH]

You miss the point- GVWR is the max weight allowed for the entire truck. The axle may be swapped for the power but that's probably about it. If nothing else has changed, the GVWR won't increase so if heavier driveline components are used, it comes out of payload and tow ratings. Worrying about 100 lbs is silly anyhow.

[EX-F150 owner]

Agreed - the 6.2L will physically out-pull the 5.3L - it's a no brainer.

 

The engine blocks are basically identical, and I'd be willing to bet they run the same exhaust (unless someone can say for certain that the 6.2L runs bigger pipes? ... but I doubt it).

 

Big3 probably hit the nail on the head, that the tow rating probably factors in the truck weight, which is likely higher in the 6.2L trim levels.

The 6.2L does have a bigger exhaust. Not that I feel it adds weight into this equation.

[2014big3]

2014Big3,

 

I have a question. Based upon the information above, do you have a feeling on how the two vehicles (6.2L/3.73 vs 5.3L/3.73) would compare on fuel consumption if both were pulling a 6,000 lb trailer, at say 60 mph.? The 6.2l uses more fuel unloaded, but if both were loaded equally, the 6.2l would not have to work as hard. Would that have any impact, and what kind of numbers could one expect? Thanks in advance for any insight.

 

Johnny

Hi Johnny

 

Hi Johnnyye

 

This answer is more of a guess whereas I'm very confident of the previous one. At present the EPA rated difference between the 5.3 and 6.2 is roughly 10 or 12% . I did'nt look up the exact difference but that's easy to find on the web and I did know exactly a couple of weeks ago. I'll call it 2 mpg on the highway unloaded at 60 mph. So it's somewhat close to begin with. Once towing 6000 lbs trailer as you suggest I would expect the difference to close entirely.

 

Further I read where GM engineers discussing the new 6.2 Vette motor said the reason they stayed with such a big displacement is that they found the motor was very comfortable in 4 cylinder mode and as such it gets fine mpg. My guess is that answer can be extended to the 6.2 truck now that it unlike the last 6.2 it can run on 4 cylinders. EPA ratings are done in a indoor laboratory on a dyno with no wind ! In real life pickups fight wind and a 6.2 might very well run on 4 cylinders more often than 5.3 that might be switching in and out more often. I'm guessing even unloaded the new 6.2 is going to be closer in real mpg to the 5.3 than most would guess. If you live at any altitude or in a windy region I think my best guess looks better still.

[Johnnyee]

Hi Johnny

 

Hi Johnnyye

 

This answer is more of a guess whereas I'm very confident of the previous one. At present the EPA rated difference between the 5.3 and 6.2 is roughly 10 or 12% . I did'nt look up the exact difference but that's easy to find on the web and I did know exactly a couple of weeks ago. I'll call it 2 mpg on the highway unloaded at 60 mph. So it's somewhat close to begin with. Once towing 6000 lbs trailer as you suggest I would expect the difference to close entirely.

 

Further I read where GM engineers discussing the new 6.2 Vette motor said the reason they stayed with such a big displacement is that they found the motor was very comfortable in 4 cylinder mode and as such it gets fine mpg. My guess is that answer can be extended to the 6.2 truck now that it unlike the last 6.2 it can run on 4 cylinders. EPA ratings are done in a indoor laboratory on a dyno with no wind ! In real life pickups fight wind and a 6.2 might very well run on 4 cylinders more often than 5.3 that might be switching in and out more often. I'm guessing even unloaded the new 6.2 is going to be closer in real mpg to the 5.3 than most would guess. If you live at any altitude or in a windy region I think my best guess looks better still.

2014Big3,

 

Thanks for the response. One more question. Do you know how much the 3.73 gearing will effect mileage over the 3.42 gearing. I drive like a little old man (Oh wait.... I am a little old man (well maybe not little)), so I'm not concerned with me having a heavy foot. I live outside of Houston, so driving around here is mainly flat. I'm trying to get a feel how much of a hit I will take under the EPA ratings with the 3.42 gear test truck. As for my highway speed, 65 to 70, max (like I said, .....old man driver). Thanks

 

Johnny

[Prokopchuk_9]

Either truck would be sacked right out if you went to the Max rating anyways.

 

 

[AgDoctor]

Probably a 1-2 mpg difference on 3.73.

 

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[2014big3]

2014Big3,

 

Thanks for the response. One more question. Do you know how much the 3.73 gearing will effect mileage over the 3.42 gearing. I drive like a little old man (Oh wait.... I am a little old man (well maybe not little)), so I'm not concerned with me having a heavy foot. I live outside of Houston, so driving around here is mainly flat. I'm trying to get a feel how much of a hit I will take under the EPA ratings with the 3.42 gear test truck. As for my highway speed, 65 to 70, max (like I said, .....old man driver). Thanks

 

Johnny

Hi Johnnyee

 

Your welcome.

 

Again my answer is a good best guess. First remember the EPA ratings never get specific to gear ratio. Your literal question asks how much of a hit you'll take under the EPA ratings. That I can't answer. The question I think you meant to ask ( correct me if I'm wrong ) is the real life mpg difference between driving at 65 mph with a 3.42 vs 3.73.

 

I agree with "pineland" about 1-2 mpg , with 2 mpg being the max difference.

 

Unloaded in overdrive a 2014 4X4 with 18" rims will turn at close to 1615 rpm ( 336 X 342 X 65 / 31 X .67 ) 336 is a formula constant, 342 is the gear ratio ,65 is your mph, 31 is the tire diameter, and .67 is the overdrive ratio. Using the same formula a 373 will turn at 1750 rpm. In real life this is small difference 1615 (342) vs 1750 (373). My good best guess is 1 mpg unloaded at 65 mph. Add trailer or wind and the difference will be very small indeed. Remember wind is your enemy in three of four directions with respect to mpg.

 

I made a small error in a previous post. the 1.53 transmission gear is 3rd not 4th. This does not change the equation or my answer for the likely rpm towing a 6000 lbs tralier at 55 mph.

 

In your case I think a 6.2 with a 342 will be almost as efficient as a 5.3 with a 373 and for sure more fun! The city non freeway commuting mpg is the only place I think a 5.3 is definitely better.

[2014big3]

Anyone still interested in 5.3 vs 6.2 MPG can search 2014 Canadian Truck King Challenge. They tested many 2014's including two 5.3 and two 6.2 on various criteria including MPG under three different scenarios Tow ( approx 6000lbs ) Payload ( approx 1000lbs ) Empty They found the 6.2 did very well indeed, 6.2 within 1 mpg or less under all scenarios. They did not specify rear end in the tests. I do know they used a Denali and High Country for the 6.2's which cannot be ordered with Max Tow ( 3.73 ) on the Canadian GM site, therefore 3.42 for the 6.2's BTW all trucks in test were 4x4.

 

I'll be buying a 6.2 if I get one. I don't tow heavy but given a number of complaints about the lazy throttle response on the new 5.3 and the apparent very close MPG of the two why not! Also a tow test on youtube ( the fast lane truck or something similar ) of a 5.3 vs 6.2 with the same trailer, no contest , 6.2 burns rubber with a pretty good sized trailer!

[Johnnyee]

Anyone still interested in 5.3 vs 6.2 MPG can search 2014 Canadian Truck King Challenge. They tested many 2014's including two 5.3 and two 6.2 on various criteria including MPG under three different scenarios Tow ( approx 6000lbs ) Payload ( approx 1000lbs ) Empty They found the 6.2 did very well indeed, 6.2 within 1 mpg or less under all scenarios. They did not specify rear end in the tests. I do know they used a Denali and High Country for the 6.2's which cannot be ordered with Max Tow ( 3.73 ) on the Canadian GM site, therefore 3.42 for the 6.2's BTW all trucks in test were 4x4.

 

I'll be buying a 6.2 if I get one. I don't tow heavy but given a number of complaints about the lazy throttle response on the new 5.3 and the apparent very close MPG of the two why not! Also a tow test on youtube ( the fast lane truck or something similar ) of a 5.3 vs 6.2 with the same trailer, no contest , 6.2 burns rubber with a pretty good sized trailer!