Tow/Haul mode = Sports mode!!!!

Willshire · January 11, 2016

I'd like to know the details on this. So they modified your tow haul mode how? Is it still optimized for towing?

How is your tune for regular drive then?

My tune is in progress with Blackbear so id like to consider this.

So, i asked for my shifts to be firmer than when not in T/H mode, jacked my rev limiter to 6000rpm, WOT shifts at 6000, This was in my 08. 1-2 shift was pretty hard at light throttle but if i was racing a dodge or ford it was WOT anyway. I raced my BB tuned 08 (Z71)against my BB tuned 02 (2wd) and they were pretty close. more was done to the 02 than the 08.

Justin provided a Stock, sport, and tow tune files so if i was towing i would put the tow tune in. Just ask him about the sport mode and he will explain what he does. I assume higher shift pressures to the clutches is one of them. My 08 ran flawlessly up to the sale date and had 240,000 miles on it and i only replaced the starter and the radiator in 4 years

Edited January 11, 2016 by Willshire

newdude · January 11, 2016

It makes absolutely no sense that you would get BETTER mpg with Tow/Haul - it keeps your RPMs higher and delays up-shifts. By definition, you're burning more gas. Unless something has changed, there is no change to the engine tuning, it only changes shifting.

I experimented with my 2012 and this tow/haul driving all the time. Yes, it runs AFM much more, but it never sees 6th gear so it dropped into AFM in 3rd, 4th and 5th. MPG did drop for sure. Anyone experimenting with this whole deal has to run a tank or two each way to see what the differences really would be.

Interesting note, E85 and leaving it in D, AFM would run longer as well.

gmckenzie · January 12, 2016

Set it and forget it. Shift to M, click up to 5 and it will shift like an automatic until you shift out of M.

Just know that if you shift to M6, the AFM is turned on again. But in M5 it stays off. So all you lose is the second OD.

I just wish there was a way for it to go into M5 by default.

redwngr · January 12, 2016

wait so you are saying I can put it in M5 and drive around and it will shift up through the gears normally but stay out of V4? It won't just stay in 5th? or do you need to shift your way up to 5th with the buttons?

Correct.

In M5, it will use any gear it thinks it needs, up to 5th.

In M4, it will use any gear it thinks it needs, up to 4th.

etc.

Edited January 12, 2016 by redwngr

Travis Whitmore · January 12, 2016

I may have to try the M5 out. What I like about tow mode is the shifts feel much cleaner and quicker.

Edited January 12, 2016 by TeeDub21

gmckenzie · January 12, 2016

I may have to try the M5 out. What I like about tow mode is the shifts feel much cleaner and quicker.

They do 2 different things. If you like the way it shifts in TH, use it but try the M5 as well to stop the V4 mode.

shockedimpy · January 12, 2016

M5 mode elimates 6th gear though? For highway use? I've tried it in TH mode and the truck feels better, it may be a mental thing. I'm not a fan of it shifting at 2,600 RPM from 1st to 2nd though. A tad bit too high

redwngr · January 12, 2016

M5 mode elimates 6th gear though? For highway use? I've tried it in TH mode and the truck feels better, it may be a mental thing. I'm not a fan of it shifting at 2,600 RPM from 1st to 2nd though. A tad bit too high

M mode limits the transmission to whatever 'M' number you select.

You can also select M6 -- but this is the same as being in D. However, it does give you the ability to switch from D mode to M mode without moving the column lever.

wayles · January 13, 2016

Ok ladies and gentleman,

I decided to run 3 tests to get some actual numbers. Take them for what you will and know that I drive like a grandma and worked with what I have.

Specs:

- 2015 Chevy Silverado LTZ 4x4

- 3" leveling lift

- Airdam still on

- RetraxOne Tonneau cover

- Stock 20" rims and tires

- DeeZee step bars

- Running in 2WD mode

Distance:

- 10 miles exact

Terrain:

- City stop and go with occasional long stretch all flat land

Weather:

- Cloudy and 64 degrees F

Location:

Camarillo, CA

Assessment with Tow/Haul ON:

- While driving with this on for the 10 mile distance I was able to achieve 15.2mpg during which time I noticed that the RPMs consistently stayed high. Shift points seem to be smoother but at the same time the truck was staying in the same gear for longer before shifting. The hard shifting that normally ensues with my truck went away. The truck DEFINITELY has more sport to it. From a dead stop there is no delay and the throttle is more responsive and more aggressive.

Assessment with Tow/Haul OFF:

- While driving with this on for the 10 mile distance I was able to achieve 19.7mpg during which time I noted normal shift points. The shifting is definitely more rough but the rpms constantly stayed down keeping the truck in a higher gear. There is definite difference between having Tow/Haul engaged and not having it engaged when it comes to throttle responsiveness.

Selective Tow/Haul Engagement:

- As I was reading through the comments I noted some people saying that the truck remains in gears longer and stays in V4 mode longer. I got to thinking about that and decided to try one more experiment with selectively engaging the Tow/Haul button when in v4 mode to keep the truck there longer. This actually yielded some surprising results. Driving the 10 mile stretch while engaging the button each time my truck entered v4 mode yielded 21.7mpg! Granted, engaging it each time and disengaging it when v8 came on was kind of a pain, but an argument can be made for long distance driving where v4 engages more often and for longer periods. On the freeway my truck stays in v4 most of the time at 70mph but kicks into v8 when a slight hill comes up. If the truck could be forced to stay into v4 during these transitions to small hills, there might be quite a significant increase in mpg.

This is just a rough test and I actually plan on doing a freeway test today if I end up going back out. The test will be a 20 mile approx test but I will have more exact numbers when I do it. Let me know if anyone else attempts this or tries this out on the freeway.

The truck:

Interesting results. Thanks for taking the time to do this. I'm anxious to see the results from your freeway test.

Jerry Burdey · October 21, 2021

On 1/10/2016 at 12:06 PM, Justin Nachazel said:

This is awesome I'm going to ha e to try it today. So question... If this is so much better then why doesn't GM just factory have their trucks tuned to something similar if its increasing torque, decreasing wear, and increasing mpg?

Does anyone have any solid numbers on mpg?

Because they design cars these days where u can't work on them because of all the computers so u have to spend money alot of it at shops preferably their shops of course, they design things to wear out quicker and build things cheap so u have to come back and spend money, if cars were built like they were in the old days, easy to work on and reliable you wouldn't have to buy as many cars cause it would last you forever this they get less money..