Why does 6.2L have less towing capability than 5.3L?

[Yukon Owner]

I want to change my 2015 GMC Yukon for a 2021 Yukon or Sierra to get better towing capability.  Would someone please explain to me why the 5.3L engine (rated at 355 hp & 383 lb ft of torque) is rated for a higher towing capability (8,400 lbs towing for the Yukon, 9,200 lbs for the Sierra SLT) than the 6.2L engine (rated at 420 hp & 460 lb ft of torque) (8,200 lbs towing for the Yukon, 8,800 lbs for the Sierra SLT) if both have the same 10-speed transmission, 3.23 gear ratio, and 4WD?  I know there's probably a few hundred pounds difference in weight between the 5.3L and 6.2L engines, but you would think 65 hp and 73 lb ft of torque would provide some increase in towing capability.

 

Thanks in advance for the info!  I want to tow an enclosed car trailer, don't want to go diesel (because I'll use the truck as a daily driver), but want better towing capability than my 2015 Yukon with the 5.3L.  I was going to buy a 6.2L, but I'm trying to understand why I won't get better towing capability (at least not on paper) than the 5.3L.

[CamGTP]

The 5.3 to 6.2 weight difference is more like less than 50lbs. It's just a bigger bore with larger pistons and few other minor things. The overall size of the engine is exactly the same, it's all internal changes and a different intake plenum and throttle body.

 

Towing capacity is goofy with GM.

 

 

The crew cab short bed is 8,600lbs and the crew cab standard bed is 9,000lbs with the 3.23 gears. If you get the max towing package it jumps up a lot to 11,700/11,800lbs. That's for the 6.2 engine.

 

[JR09country]

The 5.3 to 6.2 weight difference is more like less than 50lbs. It's just a bigger bore with larger pistons and few other minor things. The overall size of the engine is exactly the same, it's all internal changes and a different intake plenum and throttle body.
 
Towing capacity is goofy with GM.
 
 
The crew cab short bed is 8,600lbs and the crew cab standard bed is 9,000lbs with the 3.23 gears. If you get the max towing package it jumps up a lot to 11,700/11,800lbs. That's for the 6.2 engine.
 

This right here ^^

Plus, I assume cooling has something to do with the ratings. I wouldn't think the 5.3 requires significantly less cooling than the 6.2 but it could have something to do with it outside of the max tow package.

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[Yukon Owner]

Thanks, I appreciate the info, but still don't understand why all other factors being the same (same truck, same cab & bed, same trim level, same gears, both 4WD), why the 5.3L has a higher tow rating than the 6.2L.

[MTU Alum]

The differences are likely due to the SAE j2807 procedure.  For vehicles under 8600 lbs GVW, the vehicle must use EPA mass for its trailer calculations.   For EPA  mass, you must include any option that has over 33% take rate into your base vehicle mass.  The 6.2 trucks are higher option content so higher base vehicle mass than 5.3.  If both 5.3 and 6.2 have same GVW, the 6.2 will run out of payload before 5.3.  

 

This is the same reason why GMC usually have lower fuel economy and trailer weight ratings than Chevrolet.  

 

The only way to get around this is too have higher GVW, RGAWR, or GCW depending on which one is the limiting factor.  

 

There could be other reasons as well.  Google SAE J2807 if you want a trailer certification lesson.

 

#iworkforGM 

[C/K Man]

At least GM follows J2807, I hear some other manufacturers don't.........

[Yukon Owner]

22 hours ago, MTU Alum said:

The differences are likely due to the SAE j2807 procedure.  For vehicles under 8600 lbs GVW, the vehicle must use EPA mass for its trailer calculations.   For EPA  mass, you must include any option that has over 33% take rate into your base vehicle mass.  The 6.2 trucks are higher option content so higher base vehicle mass than 5.3.  If both 5.3 and 6.2 have same GVW, the 6.2 will run out of payload before 5.3.  

 

This is the same reason why GMC usually have lower fuel economy and trailer weight ratings than Chevrolet.  

 

The only way to get around this is too have higher GVW, RGAWR, or GCW depending on which one is the limiting factor.  

 

There could be other reasons as well.  Google SAE J2807 if you want a trailer certification lesson.

 

#iworkforGM 

Thanks a lot--I appreciate it!