Marky Dissod
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What's your axle gear?
Chevrolet Suburban 3500 Questions
- Thread starter Bigburb3500
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That is generally my towing experience as well, with the 6.2. I can usually accelerate uphill to pass, if needed, if I don’t mind winding it out. Where I was struggling was on a 9% grade trying to hold 55. I could do it but I didn’t want to wind it out that hard, so I held 45.
The duramax conversions are amazing, and I would buy one if I could justify the expense. A bigger camper might be just the justification I need
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strutaeng
Full Access Member
@Geotrash was it you that mentioned in another thread towing should be done near/at peak TQ RPM? (I may be confusing you.) I was going to reply to that comment someone posted, but really wasn't sure and I chatted with my buddy about it. Again, if that wasn't you, I apologize.
So after looking at TQ/HP curves for some of the common engines on these full sized vehicles, I believe it should be somewhere between peak TQ (3500 rpm-ish) and peak HP. Perhaps peak TQ to get going, but to get the most juice of the engine and during highway speeds to maintain speed, closer to peak HP. I know on the LS engines, that pushes you like in the 5,500 RPM range. But I think that's typical of most has engines. I think it boils down to the TQ vs. HP argument, that's were my buddy and I wound up, lol.
The reason with the diesels tow so nice is that peak TQ and peak HP RPMs are very close, and obviously more slower revving than a gas engine. I want to say something like 1800 RPM and 3,000 RPM? And of course, the huge TQ numbers.
So after looking at TQ/HP curves for some of the common engines on these full sized vehicles, I believe it should be somewhere between peak TQ (3500 rpm-ish) and peak HP. Perhaps peak TQ to get going, but to get the most juice of the engine and during highway speeds to maintain speed, closer to peak HP. I know on the LS engines, that pushes you like in the 5,500 RPM range. But I think that's typical of most has engines. I think it boils down to the TQ vs. HP argument, that's were my buddy and I wound up, lol.
The reason with the diesels tow so nice is that peak TQ and peak HP RPMs are very close, and obviously more slower revving than a gas engine. I want to say something like 1800 RPM and 3,000 RPM? And of course, the huge TQ numbers.
gtrslngrchris
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I don't really have anything useful to add but I'll chime in to say that even with cracked up pipes giving me a pretty solid exhaust side boost leak my LB7 Duramax just laughs off towing my drift car compared to the 6.2 in the Denali. It's not even close.
BacDoc
Full Access Member
As someone who’s been towing boats on trailers for years, I have learned by listening to some smart trailer people and found with experience they are usually right about
“Max towing”. Couple important points:
Trailer balance, tires and tire pressure, axle ratio, the hitch and how it’s mounted can all affect the performance.
The “Max” towing weight is only a limit number that includes the total weight of trailer, cargo and everything that goes on the hitch. This max is for level roads, normal driving and braking.
You never ever want to tow the “Max” as your regular routine. It’s more of a limit. If you’re maxed out then your tires brakes and suspension are at the limit and these components will fail at that limit.
If your route involves significant elevation, speed or distance you should take a percentage off max. Example is if you are going up/down steep grades that percentage should be proportional to the gradient. My 2024 Tahoe 6.2l RWD has something around 8k max, if I was towing in mountains I would never tow over 7k and I would be closer to 6k lbs for peace of mind.
If you’re driving high speed for long distances you should consider braking distance at speed. If max is 10k lbs and you want to go 70+mph you don’t want to tow 10k!
Safety, wear and tear on tow vehicle and ease of mind are the key factors. From my experience, 70% to 80% of max rating is a good recommendation for the “Max” weight you want to work with for safety and health of the tow vehicle. Conservative values are wise choices. Choose wisely!
“Max towing”. Couple important points:
Trailer balance, tires and tire pressure, axle ratio, the hitch and how it’s mounted can all affect the performance.
The “Max” towing weight is only a limit number that includes the total weight of trailer, cargo and everything that goes on the hitch. This max is for level roads, normal driving and braking.
You never ever want to tow the “Max” as your regular routine. It’s more of a limit. If you’re maxed out then your tires brakes and suspension are at the limit and these components will fail at that limit.
If your route involves significant elevation, speed or distance you should take a percentage off max. Example is if you are going up/down steep grades that percentage should be proportional to the gradient. My 2024 Tahoe 6.2l RWD has something around 8k max, if I was towing in mountains I would never tow over 7k and I would be closer to 6k lbs for peace of mind.
If you’re driving high speed for long distances you should consider braking distance at speed. If max is 10k lbs and you want to go 70+mph you don’t want to tow 10k!
Safety, wear and tear on tow vehicle and ease of mind are the key factors. From my experience, 70% to 80% of max rating is a good recommendation for the “Max” weight you want to work with for safety and health of the tow vehicle. Conservative values are wise choices. Choose wisely!
Bigburb3500
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Geez man, this was a Suburban 3500 GASSER thread and now we wound up talking about diesels and how great they are… you’re gonna cost me more money now because I have to diesel swap and join the Duramax forum!
Will anyone contribute to a Go-Fund me?
strutaeng
Full Access Member
Yeah. No kidding. It's like comparing apples to oranges...
There's plenty of 6.0/4L80e or 6.0/6L90e in the motorhome RV world in the GCWR of like 20,000 lbs range. Those guys aren't winning races, but they are getting to their destinations safe and sound... nothing wrong with the gas drivetrains.
Bigburb3500
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You are very correct. I told my dad the same thing - that’s how he ended up with a 3/4 ton to tow a 6-7k lbs boat. He’s in that 70-80% capacity range and gives him safe margins while traveling with it.
My use is planning to be a bit different. I will not be traveling with my planned boat purchase. I just don’t want to pay wetslip fees and be able to haul it out for the winter of low use times. Keep it in dry dock and be able to do maintenance. Furtherest it MIGHT go is 2hr but that might be 1 time ever other yr.
Glad you brought up the safety and vehicle component issue.
No need to apologize. But yes, I have had conversations about that topic and I know others here have spoken about it too. I don't think I would have said "should" about towing near/at peak TQ/RPM, because there are many factors that play into it. I think it's safe to do so, such as when pulling up a long grade trying to keep up with traffic, but equally important to me are considerations for which path through the transmission is strongest (e.g. the 4th gear path is stronger than the 5th gear path, according to nick transmissions). And, while the LS engines seem quite happy winding out to higher RPMs all day long, I spend most of my time when towing well below the peak power band because I don't need the extra power unless I'm climbing a hill.
Today, we pulled our camper 7 hours home from West Virginia through the mountains of southern PA, Maryland and Virginia, with many 8-9% hill climbs. I spent most of my time in 4th at 2800 rpm, with occasional downshifts to 3rd and 3800-4000 RPMs when needed to keep up with traffic at 65 or so up the steeper grades. It seems perfectly happy there, staying nice and cool. On the outbound trip, we encountered one super steep hill on a 2-lane road where I had to downshift to 2nd to hold 35-40, but that's all.
Edit: I should add that by "nice and cool", what I mean is that my temp gauge stays in the center 99% of the time, except for 2 or 3 times climbing steep, very long (many miles long) grades when the gauge would briefly climb to the 3/4 mark before coming back down, even if I was still climbing. Yes, I know how this gauge is calibrated and that it's only a relative reference. Also, the transmission temp held 187-190 for most of the drive, but would hit 205 by the time I crested a long hill, then quickly cool down on the descent. The only exception was on that one climb where I had to hold 2nd for a couple of miles of steep climbing where the transmission hit 217º, briefly at the top. This, with an aftermarket Derale cooler mounted below the front bumper and behind the lower grille.
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swathdiver
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I remember Eric at Duraburb saying that those were not made to tow but to carry a lot of weight (armor). Give him a call and check out his youtube channel.
