Uphill Shifting Question

[Habbi98]

Jcperform, I am just curiosity what your fuel economy is when pulling your trailer? I am running a similar setup and am getting what I think is horrible fuel economy, I am getting <7 mpg.

[Longshot270]

To help readjust your ears you could set one of your PIDs as COMM GEAR. This is Commanded Gear and says not only which gear you are in but also the status of the torque converter.

[Jackpine]

Originally Posted by Longshot270

To help readjust your ears you could set one of your PIDs as COMM GEAR. This is Commanded Gear and says not only which gear you are in but also the status of the torque converter.

Readjust what? I'll have to remember this, now that I'm entering my "twilight years", when hearing, and so on, starts to decline.

- Jack

[88Racing]

Originally Posted by Longshot270

To help readjust your ears you could set one of your PIDs as COMM GEAR. This is Commanded Gear and says not only which gear you are in but also the status of the torque converter.

I didn't know hearing aids had the display output for gears...hmm I better pay attention....

[Longshot270]

Originally Posted by 88Racing

I didn't know hearing aids had the display output for gears...hmm I better pay attention....

No, but there's and App for that.

[stl454]

Habbi98

I have a2010 supercab max tow with 5.4 and 3.73 gears. Gryphon with 87 towing tune. On average I get 10mpg running 65mph. If lots of hills it gets 8.5 to 9 mpg.

[Jackpine]

stl454, that mileage looks pretty good to me. I get about 12.5 mpg pulling our 3600# HiLo telescoping trailer at 65 mph. The "telescoping" feature means it has a smaller frontal area and much less wind resistance than you would have (towing height is only 72").

Habbi98, you didn't say what speed you tow at. If it's anything over 65 mph, your mileage is going to be KILLED due to the increased wind resistance and, you are really unsafe, since trailer tires are supposed to be kept to 65 mph max. I've learned a lot about trailer tires since getting our trailer, and I've got to say, I "baby" them now (also use the highest load range rated tires I can fit). The OEM Goodyear tires I had on the trailer both failed at 5000 miles within 2 years due to cord separation.

- Jack

[Habbi98]

Jack - the speed I tow at doesn't appear to be a factor in my MPG. I've towed it at 65-70max and at 55-60 and it appears to be the same either way. My dad has a 1500 GMC with a 5.3L and is getting 2-3mpg better when hauling this trailer in the same conditions. I have made minor performance mods (Headers, exhaust & Programmer) in an effort to increase the performance of my truck and it seems that it has hurt more than helped which is why it is frustrating to me. The truck has all kinds of Power on the Low End it's just at the Top End where is seems to be lacking the Power. I called Bill a couple of weeks ago and he said that it's possible that the tune may have had an issue with the programming so he is going to rewrite it and see if is any better. I hope it was just a programming issue because i can't afford <7mpg on a 1000mile round-trip haul.

[Jackpine]

Habbi - Thanks for clarifying. Things really get complicated when you try to compare the performance of one brand of truck to another, even doing identical tasks. I know I got better gas mileage pulling my trailer with my old, 6-cyl Nissan Frontier than I do with my F150, but I sure find pulling it a whole lot easier with the bigger vehicle. The combination of engine size, vehicle weight and gearing in the GMC may be making the difference.

If you have 3.55 gears, your truck doesn't have the factory tow package I think. So that, in combination with your tire size may make it hard for you to beat the GMC. Think of it this way: your truck might be "factory optimized" for "non-towing" driving. Yes, a programmer can help, but you may not be able to expect miracles.

Out of curiosity, what kind of highway mileage do you get when NOT towing? I currently get between 15.0-15.5 mpg. (This is on long Interstate trips.)

- Jack

[Habbi98]

Jack, What you said makes perfect sense. With that being the case i may look into a Gear Upgrade, to something that is a little more aggressive for towing. As I am not as concerned with my "Non-Towing" mileage because the main purpose of my truck is going to be hauling my camper. I have another vehicle for my daily driving. Any suggestions on Gear size? Would like to be able to run 33's and still have the towing power.

On the "non-towing" mileage i just went on a 600mile trip and was only able to get between 12-13mpg. Mileage was great with the Stock Program and factory manifolds (16-17mpg) but as soon as i replaced the cracked manifolds with the set of LT Headers it went south.

-Habbi-