5.3L Sustained RPM Towing Up Steep Grade

[jamoody]

I see from the literature that the 5.3L engine produces max torque at 4100 RPM. Does that mean I can safely (in terms of engine durability) tow up long grades (Rockies) at 4100 RPM? Can I run 4100 RPM for 30 mins at a time in whatever gear is needed to keep my transmission temp around 200? Or are published max torque RPM numbers a marketing tool rather than a real world use number? I want to be sure I don't damage the engine/transmission doing something stupid while towing in the Rockies next month. Thanks.

 

[SnowDrifter]

Max torque at rpm is just that. It's the RPM where a given engine has the greatest rotational strength

Just put your truck in tow mode and let it figure the rest out. It's a value at a number, not what it has to be for a given operational circumstance (towing up a mountain)

 

[jamoody]

Will it hurt the engine to run at such high RPM for sustained periods? I don't want to over rev the engine and tear it apart trying to get up a hill.

 

[SnowDrifter]

If you're this on the edge of the tow limit that you're worried you can't drive up a hill, perhaps it would be worth investing in a proper tow rig? 4100rpm is fine

 

[Doubeleive]

your going to be at all kinds of rpm's and gears, your not going to be sitting there at 4100 rpm solid, like chris said just put it in tow/haul and drive, your going to be on the road with trucks much bigger and much slower and your going to get stuck behind them or blended in the crowd.

 

[swathdiver]

Will it hurt the engine to run at such high RPM for sustained periods? I don't want to over rev the engine and tear it apart trying to get up a hill.

These LS motors were bred to spin all day long. Not going to hurt it in the least. Your motor makes a lot of torque and will handily maintain the higher gears while towing in most situations. If your total weight is within 75% of GCWR, stick it in Tow/Haul mode and use M4 or M5 if needs be in the mountains. 4100 is where the torque peaks at, though it's a pretty flat curve. From about 2000-5500 rpms the motor is making over 330 ft lbs of torque.

Click the download on this page to see the power graph:

http://www.gmpowertrain.com/engines/5-3l-l83.html

She'll do just fine hauling within specs.

 

[the blur]

You can take the motor, and beat on it until the oil temps are 320 degree's, then do it again & again... no matter what any one says.

 

[Bobby Hill]

I have an 01 Tahoe LT, 200k mi, 3.73 gears, 5.3l engine and 265 tires. I live in the small mountains of Maryland, 3360ft max. Not the Rockies!

I needed to bring my 1966 Mustang from Southern MD, flat lands to my new home. My truck was down so I used the Tahoe and a Uhaul trailer to bring the Mustang up. It did not like the journey once I started up the mountains. It worked hard and the check engine light flashing on an off the entire time when running up the mountains. It made it, Yes, I'm not used to running a V8 engine that hard for that long. The only exception for me was when I was racing back in my younger days and I built the engine to handle high rpm's..... for a 1/4 mile.

So yes, it will do it. I like my Tahoe and it is my comfortable traveling car. I will keep my towing duties to my 3/4 ton pickup from now on.

Just my $ .02 for what its worth.

 

[Big Mama]

The engine is going to sound like it’s ready to let go. You’re used to driving it around 2k rpm so 4100 or so will worry you but it’ll keep going. As Chris mentioned the key is the weight. Tow mode will seem odd at first due to shifting at higher rpm up hill but that’s what it’s for. I figure the folks that designed it are much smarter than me. Which doesn’t take much.

 

[jamoody]

Thanks, guys. You've put my mind at ease, at least as I sit in my living room. The Yukon only has 5K miles on it, and only 1K of that towing, so I don't have much experience with it yet. The proof will come when we set out for a 2 month trip through the Rockies next week from the east coast Westward **!