"shop-teacher" (shop-teacher)
05/28/2014 at 07:29 • Filed to: Towing
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"shop-teacher" (shop-teacher)
05/28/2014 at 07:29 • Filed to: Towing | 0
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I drive an '06 GMC Sierra Crew Cab, and it's been a fantastic truck. It has the small 4.8L LS and a 3.20:1 rear end ratio, so its not exactly optimized for towing. This was never an issue, but I bought a camping trailer last month. It weighs about 4000lbs loaded, and I took it on its first trip last weekend (to the Indy 500).
Now, its not that I can't tow it, but that little 4.8 is working HARD to do it. Most of the trip I couldn't even get into 4th gear, so fuel economy dropped to 11.5 mpg. To get any decent acceleration, I was really having to wind it out too.
I'm thinking about putting a 3.73:1 rear gear in. I know that will help with acceleration, but will it also give me the torque multiplication I need to cruise in top gear? Or am I just trading one problem for another?
Of course a new truck could solve all, but I'd rather spend that money on something more fun than just another truck.
Mattbob
> shop-teacher
05/28/2014 at 07:32 |
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http://www.summitracing.com/search/departm…
The man in the iron mask
> shop-teacher
05/28/2014 at 07:33 |
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Practice in GTA V. Borrow a Pickup that is towing a boat, and then reverse into parking lots. Or unload the boat to the sea to get the basics of reversing with a trailer.
( i know probably you didnt ask for this, im too lazy to read right now, its 6 am and i havent slept yet)
Meatcoma
> shop-teacher
05/28/2014 at 08:01 |
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What kind of mpg do you normally get, if you are basing this on regular cruising with overdrive then you are gonna have a bad day. How often are you going to tow this trailer? How far are you towing the trailer? I assume you are towing with O/D off anyways so switching your o/d gear out won't help much.
You can work out a pretty good guess as to how much money you are losing but I don't think swapping in a rear end will net you any significant savings.
E92M3
> shop-teacher
05/28/2014 at 08:11 |
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I would think gears will only hurt your MPG even further. If you're going to tow you're going to use a lot of gas. No way around that. I don't know anything that will tow 4000 extra lbs and still get 15MPG. Anything that will tow 4000lbs with ease is going to be lucky to get 15MPG when its NOT towing. Except a few diesels. You may get better mileage with a diesel, but you'll be making up for it each time you fill up.
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shop-teacher
> Mattbob
05/28/2014 at 08:20 |
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I actually considered a blower. Too much $$$ though
BigBlock440
> shop-teacher
05/28/2014 at 09:26 |
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Depends on how much highway driving you usually do empty. The 3.73 rear will drop your highway mileage (not sure by how much because you've got overdrive, my car didn't), but in theory should allow a lower cruising rpm when towing. I'm assuming 4th is 1:1. Shorter tires would also help, but I haven't done the math to figure out how much. I don't know how difficult it is to swap gears on a GM, but on my car it was a few hours and $300 for the new gear set. Also, if it's 4wd, you'll need to do something with the front also.
AMGtech - now with more recalls!
> shop-teacher
05/28/2014 at 10:10 |
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just live with it, you will never get back the money you put into it. I used to have an 03 Sierra with the 6.0 and pulled a 6k trailer daily, averaged 12mpg and could still out accelerate most econoboxes and do 70mph comfortably (without OD of course).
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shop-teacher
> AMGtech - now with more recalls!
05/28/2014 at 11:11 |
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I'm less concerned about money as I am about keeping the motor from needing to be wound up tight all the time. I want it to live to 200k miles. The 6.0 has a lot more torque than my 4.8.
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shop-teacher
> BigBlock440
05/28/2014 at 11:15 |
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I don't do much unloaded highway driving anymore, and the truck is 2wd. 4th gear is overdrive for me, but the owners manual says towing in OD is fine.
wabbalosthiskey
> shop-teacher
05/28/2014 at 11:17 |
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If you are going to haul the camper around regularly, do a gear swap. The truck has plenty of overdrive gear I am sure, I'd go right for 4:10s and add a bigger transmission cooler. Get a tuner device of some sort that will adjust the tranny calibration and get it in lockup sooner. All of these things will make it significantly easier on the truck, likely get you slightly better gas mileage when towing with a minor difference when unloaded, and be much more tolerable to haul with. Just remember if you have a 4x4 you're doing it twice.
If you end up towing/hauling a lot, then you'll probably find yourself looking to change trucks. Just have to decide what works best for what you really do.
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shop-teacher
> Meatcoma
05/28/2014 at 11:20 |
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I'm looking less for savings than I am looking to keep from having to wind the motor up all the time. My truck gets 18-19 mpg highway unloaded. I'd be happy with a towing mpg in the 13 range. I want this truck to live to 200k mile, so if a lower rear end gear ratio will let me cruise in overdrive while towing, that would be spiffy.
You can tell a Finn but you can't tell him much
> shop-teacher
05/28/2014 at 13:45 |
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Putting a 3.73 rear end will help with acceleration and towing. It will also result in your truck turning slightly higher rpm's when cruising, especially when empty. If you tow a lot it may be worth it, but if you're towing your trailer 2-3 times a year it probably isn't worth it.
And getting 11.5 mpg while towing isn't that bad. If it is a hard side camper your big issue is the increased wind resistance, not the weight. Changing the rear end won't help that much.
For reference I've got a 2011 F-150 with the 3.5EB and 3.55 rear end. Towing our ~7,000lb camper on a 180 mile round trip the computer is telling me I got around 10.5. When I fill up next I will get better numbers from my mileage tracking app, but those should be fairly close.
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You can tell a Finn but you can't tell him much
> shop-teacher
05/28/2014 at 13:46 |
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Sorry if this is a repost, Kinja is being a dick.
Putting a 3.73 rear end will help with acceleration and towing. It will also result in your truck turning slightly higher rpm's when cruising, especially when empty. If you tow a lot it may be worth it, but if you're towing your trailer 2-3 times a year it probably isn't worth it.
And getting 11.5 mpg while towing isn't that bad. If it is a hard side camper your big issue is the increased wind resistance, not the weight. Changing the rear end won't help that much.
For reference I've got a 2011 F-150 with the 3.5EB and 3.55 rear end. Towing our ~7,000lb camper on a 180 mile round trip the computer is telling me I got around 10.5. When I fill up next I will get better numbers from my mileage tracking app, but those should be fairly close.
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AMGtech - now with more recalls!
> shop-teacher
05/28/2014 at 13:59 |
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that's kind of my point I guess. The 4.8 was never really meant for serious towing on a semi-regular basis. Not terribly helpful though, I know.