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Olliethegoalie

Suggestions for settings while towing?

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I've got my 08 running on SW3, timing on #4, and everything else on default and my truck runs great unloaded. Lots of power, mileage is up from when the truck was stock, life is good. However, I finally got to pull my trailer with it for the first time since doing my deletes and tunes etc last fall, and I'm not as impressed now. The power was still good, in fact the transmission didn't shift on any of the hills that it used to, but it sucked the fuel down like it was going out of style. So my question is, is there anything I can do to my settings to help get that mileage back up a bit while towing? I've still got the stock transmission and haven't done head studs or anything like that, so I don't what to do anything too drastic obviously. I've read a lot of older posts in here where guys run SW5 on the stock transmission and haven't reported any problems, but they also don't mention towing while running it. My trailer is only about 6000lbs fully loaded, and sometimes I throw a quad in the box so there's another 800lbs or so. Nothing crazy weight wise, but enough it's noticeable. I know I'm not going to be getting big mpg numbers while towing, but I think I should be doing better than 600Km on a tank when I'm getting close to 1000km / tank unloaded!

 

Anyway, just curious what some of you guys are running while towing? Any help would be great! Thanks!

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While towing around 7k lbs, my truck would deliver between 12/15 mpg depending on terrain and climate conditions. You may increase your mileage with software SW5/7, however you have to be very disciplined with the throttle, you cannot let it pull down and lug in top gear or you surely will destroy your transmission. I would not recommend anything higher than SW3 with an oem trans, just too many variables to watch out for.

 

Without doing the conversion, what does 600km on a 34 gallon tank = mpg ?

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Thanks for your thoughts! I'm pretty hesitant to switch from SW3 to a higher setting as I don't have the gauges to monitor any EGT's, boost, or tranny temps right now. Guess I better get on that!

 

As for the mileage, I think that works out to roughly 10 mpg or so. My main concern here is that I'm getting quite a bit better mileage when I'm just driving unloaded after all my mods/tunes, but it's no better than before when I'm towing. I guess I assumed if one went up the other would follow? Not sure if that's just how it's going to be, or if I should be adjusting my programmer differently for towing? This is my first time doing this and I'm trying to learn all the tricks still! I had a guy on another forum tell me I'm running too much timing by having it on #4 while towing. I hate to say it, but I really have little clue about a lot of this stuff.

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As to timing, I also run the "greatest" setting. Like Jess stated if one would change to a higher setting one would expect the mpg to rise. Also as Jess mentioned you would need to be disciplined with the pedal. Also one needs to shift down at the correct time.

 

If driven the same way one would get better mpg towing compared to stock. If one has more power, one doesn't need to use ALL the extra power ALL the time. On one of my 5.9 trucks on a towing mpg test I noted an improvement of 4 mpg over stock, same load. My goal was to measure mpg going the same speed (65 mph) over the same hills. Hills that would pull me down to 62 mph stock with the stock tuning I was able to do 65 mph by feathering the pedal and also maintaining 65 mph throughout the run gave me an increase of nearly 4 mpg.

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So as far as the timing setting I'm running, in your opinion, is #4 (greatest) too much for towing? I was told by someone else that running it on #4 while towing I could potentially build too much drive pressure and blow my head gasket. He suggested running it on the SW3 default which if I remember is #2 and that's slightly less than #4 as far as timing goes. Any thoughts on that?

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Timing default for your truck is one step higher than stock and two steps lower than max #4. Timing #4 on sw3 should be fine IF you watch your egt's and your right foot. Otherwise go back to #3 or default.

Sw4 has stock timing as default. You have to think about how it will make power without added timing. Only a couple of ways and adding fuel is one of them. If mpg's are your goal then add timing to increase engine efficiency and mpg's.

 

"I finally got to pull my trailer with it for the first time since doing my deletes and tunes etc last fall, and I'm not as impressed now. The power was still good, in fact the transmission didn't shift on any of the hills that it used to, but it sucked the fuel down like it was going out of style. So my question is, is there anything I can do to my settings to help get that mileage back up a bit while towing?"

In your own words you're using the extra power you've added by tuning. Fuel = Power, if you use more power you use more fuel. You shouldn't be towing 6k and pulling hills at 1600 rpm. Downshift and you'll need less pedal (read less power, less fuel) to pull the hill and see your mpg's increase.

Its all about the correct power applied at the correct rpm that will reap you the best rewards.

 

Believe me, I know its tempting. I can pull my 8k trailer up into the sierra's at 70mph in locked 6th. I can pass all the cars, trucks, trailers, motorhomes and even a few Harleys with ease but I can also watch the fuel gauge drop while doing it.

Downshift, take it easy on the hills and get your mpg's up a bit.

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Well I set the timing back to the default setting for SW3 just to see if there's any difference, and I've been shifting the tranny back manually on the big hills when it starts to lug down and doesn't shift in it's own, and nothing changed. I get what you're saying about downshifting to use less pedal, but the other side of that is now running the engine at 2000+ RPM, so isn't that being a bit counter productive with the mpg's?

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By nothing changed do you mean you're getting the same mileage?

In theory even though you're at 2000 rpm you're running more efficiently, with less throttle, not sraining the lugging the engine and saving fuel. This holds true for the majority of trucks. Hopefully yours isn't one of the exceptions.

 

One question no one has asked, what speed are you trying to maintain?

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Sorry I should have clarified, but yes same mileage. I didn't calculate it on my last trip, but visually my distance/tank was unchanged. As for speed, all of our highways here are 100-110km/hour so 60-70mph. I think I'm just going to have to suck it up and deal with the fact that it is what it is while towing. It's just a bit frustrating knowing that I spent all that money on the upgrades etc for towing, but I'm only seeing the benefits of it when I'm not towing!

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The reason I ask is I've read a lot of mileage threads and it is common for the guys who tow the slowest (55-60mph) to have the best mileage and the guys who tow the fastest (70-75mph) the worst.

I'm on the border of the upper end speed with a 7000 ft altitude gain so I don't get the best mileae either.

 

I'm cautious on the timing and keep it on default. Once I get the pyro installed (too many honey-do's) I'll bump it up to the next higher one and hopefully see some better mileage.

Edited by xcc_rider

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Yeah I typically don't go above 110km/hr, especially when pulling. I need to get some gauges installed in my truck too so I can see what I'm doing to the poor thing! I'm more worried about the transmission than anything else at this point. I'm taking the trailer out this weekend, fully loaded, so I'll do the actual mileage calculation and see what happens.

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I find it hard to maintain 110 while towing (10k 5-th) especially up hills. On the flats I can do 110 since my RPMs rev at 2000rpm which is enough to keep from luging. As soon as it lungs and I see the EGTs go up and I manually shift out of o/d (rev 2500 rpm at 100kmh) and my EGTs drop by 100deg. I'm getting 14-16 mpg and typically drive 90-110. I am still experimenting with smarty jr between sw2 and 3.

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