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Torque Management and Tow/Haul mode


ZOOMY

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I've noticed on my 4.8, off the line it usually won't do a whole lot, but if you punch just right and it downshifts into first, then it goes pretty good. I did notice that the trans felt firmer and much more responsive when in tow haul mode at all speeds. I was just wondering if that removes it completely or how exactly if affects things.

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It firms up the shifts. (good for tranny)

It raises the shift points when driving normal. (bad for mpg)

 

BUT

 

When at WOT it lowers the shift points, than it would of been with Tow/Haul off. (bad for racing)

Also it does nothing to the TQ management.

 

I believe that's all there is to it. Hope It's all right.

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The tow/haul mode often has more torque management programmed into it. This is a very big difference in facto for the Vortec Max trucks.

 

 

 

 

 

THis "torque management " is overstated. It is s drive by wire engine which means the ECM controls throttle position and rate of opening. You are not "directly" in control of it. Tow/Haul is for tranny shift points and little more. When you change the shift point you do change how the engine interact with it.

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Here's a screen shot of HPTuners showing the difference between normal and performance (tow/haul in trucks) in an 05 CC 1500 4X4. This shows how much torque is removed during a shift. The numbers are the percentage of torque removed.

 

2048760_12_full.jpg

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It's not the throttle being closed, it's timing being removed by the PCM that's limiting the torque output. There are calculations in the program that determine that "X" amount timing removed = "X" amount of torque removed as a percentage.

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The torque convertor stays locked in tow/haul.  This is probably what Zoomy is feeling.

 

Vernon

 

 

 

Tow/Haul made me frikkin lose to my wife in her '05 grand am gt. I thought it couldn't hurt off the line...OOPS it nerfed my launch! I only started to catch up at 3rd gear but by then she had walked me. That pisses me off to this day she brags about how she beat the mighty v8... :cheers:

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The torque convertor stays locked in tow/haul.  This is probably what Zoomy is feeling.

 

Vernon

 

 

 

Tow/Haul made me frikkin lose to my wife in her '05 grand am gt. I thought it couldn't hurt off the line...OOPS it nerfed my launch! I only started to catch up at 3rd gear but by then she had walked me. That pisses me off to this day she brags about how she beat the mighty v8... :crazy:

 

 

 

 

 

Why would you want to race a car anyway? There lighter and smaller. You lost no matter what just because of HP to weight. Not to mention the wind restance. :-0

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The torque convertor stays locked in tow/haul.  This is probably what Zoomy is feeling.

 

Vernon

 

 

 

Tow/Haul made me frikkin lose to my wife in her '05 grand am gt. I thought it couldn't hurt off the line...OOPS it nerfed my launch! I only started to catch up at 3rd gear but by then she had walked me. That pisses me off to this day she brags about how she beat the mighty v8... :crazy:

 

 

 

 

 

Why would you want to race a car anyway? There lighter and smaller. You lost no matter what just because of HP to weight. Not to mention the wind restance. :-0

 

 

 

 

I just like being 4700lbs. and still able to have a shot at anything on the road that doesn't pull a sub 15 on the 1/4 mile.

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  • 2 weeks later...
It's not the throttle being closed, it's timing being removed by the PCM that's limiting the torque output.  There are calculations in the program that determine that "X" amount timing removed = "X" amount of torque removed as a percentage.

 

 

 

 

:seeya:

Rammer---

An amazing post, thank you. The graph you provided, that was the OEM tuning?

What's GMs answer as to why we need torque control? Is it because, with it,

nothing mechanical gets torn up?

 

The chart sure shows the ECU/PCMs ability to yank timing out.

 

For those of us that do not have torque control,

Chevy made a Knock Module that is not quite as sensitive and does

not respond to "ghost" knocking/pinging, it was/is OEM in the LT4.

It is not so quick to pull the timing out. Do you know if the LT4 Module

will fit a PCM/ECU in a Big Block??

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Torque Management is to prevent driveline damage. And YES, that's the stock settings in my 05. All other years that I have seen has torque reduction in the "normal" table and "performance"(tow/haul). My 05 only has it in the performance table.

 

I don't know anything about the Knock module, Sorry. Seems to me that the LT4 sensor would just be a less senstive sensor, if no programming is needed. The LS1 based engines, the knock sensors are adjustable in the program.

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"I don't know anything about the Knock module, Sorry. Seems to me that the LT4 sensor would just be a less senstive sensor, if no programming is needed. The LS1 based engines, the knock sensors are adjustable in the program..."

 

Rammer--

Good Morning...the Knock Module is located under a cover on the bottom of the

ECU, the Knock Sensor(s) are screwed into the block. You are right about the

LT4 Module being less sensitive, as the LT4 was/is a roller (rocker-arm?) engine that created some "ghost" knock noise. The Module's job is to retard the spark based on freq. of sounds heard from the sensors. As used on the LT1 small-block,

the LT4 Knock Module is a plug-and-play thing, no re-programming...I simply

was wondering if it would fit our Motorcoach...

 

A$$uming everything is OEM stock, how long does it take the PCM/ECU to notice

Premium fuel and start advancing the timing? 100 miles? 500 miles? 3 re-starts?

:seeya:

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