Gear ratio

[j_dizzle68]

So far, yea, ok, not surprised at all, even if it's a 2WD. 33" tall tires made your truck (NOT your engine) weaker, and 3.73 ain't much to begin with.
4.10 would improve the tow rating for a very good reason. (GM did not offer 4.30 for this truck because they offer stronger trucks.)
Long story short here: 4.30 or 4.56, depending on your NORMAL, PREVALENT usage cases, not your occasional ones.
My guess'd be 4.30 because I don't know your usage case, just statistics. If you use your truck unusually, it could be 4.56 would be better for you.

Don't know anything of the Stage 2 BTR truck cam, but willing to bet more money than I should, that the horsepower peak has moved to a higher RpM than GM OE?
If I remember correctly, the GM OE horsepower peak occurs @ ~ 5200RpM. Where / when does your horsepower peak now?

If this Stage 2 BTR truck cam has moved the horsepower peak past 5200 RpM, then odds are you made your engine more powerful, but NOT any stronger.
In fact it's very likely you made the engine WEAKER under 2500RpM. This seems to go right over far too many people's heads:
Most engines live UNDER 2500RpM for most of their lives, even when driven by leadfoots, even when they play or work too hard, even if they're undersized.
Have not yet found a cam that SHOWS that it makes MORE POWER UNDER 2500RpM on a DYNO GRAPH, even if they can categorically prove it other ways.

For the record, I do NOT recommend a looser converter. It will make your truck less drivable, less sensitive to smaller throttle inputs.
You may find it acceptable, but you WILL notice, and it'll cost you MpG whenever the torque converter is not locked, especially in 1st & 2nd, but even in 3rd & 4th.
Plus you may need to upgrade your ATF cooler one way or another (although this is ALWAYS a good idea regardless).
If you're willing to find a converter that is NOT looser yet has a higher stall RpM than GM OE, it'll be worth the considerable cost, just maybe not to you.

There are only two mods I can almost always recommend to nearly everyone:
*better axle gears - 4.30 (or 4.56, depending on how you usually use it)
*pcm tuning - done thoroughly and properly, it improves longevity and durability, not just the fun stuff cowards are afraid to improve - glad you got this done
The 3rd recommendation, I don't make as often, but I'll make it to you:
*bigger engine, or artificial aspiration - or both, if you've money to burn?

Given what you have now, you'd be PLEASANTLY SURPRISED, if not VERY HAPPY with a 6.0L & 4.10 (or 4.30 or 4.56).
What would you say to someone with a 4.3L Caprice (regardless of what gear was GM OE)? You better say 5.7L & 3.73 ...

*PCM Tuning?? I have 4 all stock GMT800's (2 06' Vortec Max's one 2wd w/3.73 and other 4x4 w/4.10, 05' Yukon, and 06' LBZ 2500HD dually) and I have been wondering if tuning would get any meaningful gains in power or reliability or because they're stock it wouldn't do anything really??? Any help would be appreciated!

 

[Marky Dissod]

*PCM Tuning? I have 4 all stock GMT800's (2 06' Vortec Max's one 2wd w/3.73 and other 4x4 w/4.10, 05' Yukon, and 06' LBZ 2500HD dually)
I have been wondering if tuning would get any meaningful gains in power or reliability?

Don't take this personally, but I'm surprised this is still a question after over 25 years.
That more GM V8 vehicles have not been tuned - even if NOT for more power / torque / throttle response! - is a failure on several fronts;
clearly most people misunderstand how the GM OE 'tune' holds their vehicles back in terms of durability / longevity, nevermind power / torque / throttle response.

Even if you stick with 87 octane, you will gain some power - my guess based on experience, about 10-15 ft lbs from 1800RpM up.
Have a more detailed discussion with your tuner about the DuraMax; power / torque / MpG gains should be balanced against powertrain durability.
More importantly, engine and transmission throttle response will quicken noticeably, and they'll both tend to run cooler and last longer (unless you abuse it).

Get the Yukon tuned first. You'll immediately regret waiting so long. Results will be even more obvious on the 6.0L trucks.
Although getting the LBZ tuned might cost a bit more, it MAY pay for itself over time, so long as your right foot behaves.

 

[CPB]

*PCM Tuning?? I have 4 all stock GMT800's (2 06' Vortec Max's one 2wd w/3.73 and other 4x4 w/4.10, 05' Yukon, and 06' LBZ 2500HD dually) and I have been wondering if tuning would get any meaningful gains in power or reliability or because they're stock it wouldn't do anything really??? Any help would be appreciated!

Most of what folks accomplish with the tuning is removing the "limits" GM provides. Everything is about tradeoffs. Even decreasing the PE delay will result in less fuel economy and more overall drivetrain wear. You have to decide if the priority is power or conservativism with the goal of maximum reliability.

 

[AuroraGirl]

The 4.3L V6 was also cheaper: 2 fewer pistons, con-rods, less iron, less steel, etc. and a little lighter. CAFE drove manufacturers to do stupid/crazy stuff to reduce weight and other items.
One thing I never understood was how many police Caprices, used by. Iti departments were made with the 4.3L V8. Maybe they wanted to slow them down.
I can't imagine a 4.3L V8 would cost less, nor weigh less than a 5.7

A detuned version which means longer fleet service and also shores up the CAFE mpg Ratings in bulk. The option also gives room to charge for the upgrade vs a standard power plant.

With regards to fleet sales, 1 mpg over half the sold cars meant you could have that many more trucks with a 5.7 instead of a 5.0 and not hurt the EPA credits

 

[j_dizzle68]

Don't take this personally, but I'm surprised this is still a question after over 25 years.
That more GM V8 vehicles have not been tuned - even if NOT for more power / torque / throttle response! - is a failure on several fronts;
clearly most people misunderstand how the GM OE 'tune' holds their vehicles back in terms of durability / longevity, nevermind power / torque / throttle response.

Even if you stick with 87 octane, you will gain some power - my guess based on experience, about 10-15 ft lbs from 1800RpM up.
Have a more detailed discussion with your tuner about the DuraMax; power / torque / MpG gains should be balanced against powertrain durability.
More importantly, engine and transmission throttle response will quicken noticeably, and they'll both tend to run cooler and last longer (unless you abuse it).

Get the Yukon tuned first. You'll immediately regret waiting so long. Results will be even more obvious on the 6.0L trucks.
Although getting the LBZ tuned might cost a bit more, it MAY pay for itself over time, so long as your right foot behaves.

No offense taken in fact I'm happy to have my years long hunch confirmed and it great detail! I appreciate the advice and I'll absolutely take it to heart! In my shade-tree mechanic common sense mind I always thought tuning stock would have to help but never looked into it because I'm new to tuning in general and to the Houston area and not sure where I could go to have someone take my "stock tuning" idea seriously and fear of getting scammed on someone not really doing much to it. As a kid I always dreamed of having the 800's so I drive them easy, but I would love to feel a little more performance sometimes when pulling trailers or just playing a little. Also really intrested in the gains in durability and longevity as I plan to keep these forever! Yukon first cause it'll wake the 5.3 up a lot? Also excited for the 6.0's as I really love them and I always wondered how they'd respond. Only had the LBZ a few months and I already love it and now want another Duramax in the fleet lol. I'll give them the a little foot from time to time but I'm much more conservative to keep all these in good shape for the long haul! Any ideas on tuners in the Houston area or is sending the PCM's off to someone a good option or would they benifit most from an "in shop" dyno tune to tweak each of them optimally? And any advice or any specifics to ask my tuner about or what to ask for to get the most out of what I'm looking to get out of it? Thanks so much for your time and the detail!

 

[j_dizzle68]

Most of what folks accomplish with the tuning is removing the "limits" GM provides. Everything is about tradeoffs. Even decreasing the PE delay will result in less fuel economy and more overall drivetrain wear. You have to decide if the priority is power or conservativism with the goal of maximum reliability.

That's a great point man I appreciate that! I drive mine pretty easy but like to mash the gas every now and again. Mostly though I'd like to just make them run better but also make them last longer too kind of a balance of everything. I'm not looking for most power possible to the point of putting longevity at risk unless it like... Hey here's all the power you can get just don't beat on hard every day and you'll be fine they I'll be fine cause I grandpa them around more than anything lol.

 

[Marky Dissod]

Most of what folks accomplish with the tuning is removing the "limits" GM provides. Everything is about tradeoffs.
Even decreasing the PE delay will result in less fuel economy and more overall drivetrain wear.
You have to decide if the priority is power or conservatism with the goal of maximum reliability.

Decreasing Power Enrichment delay only results in less fuel economy if the driver 'takes advantage'.
However, the prime purpose of Power Enrichment is cylinder cooling at sustained high loads, not more power -
GM's PE AFR is a bit too rich to make much more power - 'more drivetrain wear' doesn't apply to the engine.
Making the PE AFR slightly less rich than GM OE spec actually improves fuel economy while making more power, when the driver so chooses.
As for the 4L60E, carefully revised line pressure and shift time adjustments minimize drivetrain wear better than GM OE in certain cases -
especially in the case of the LQ9 (again, unless the driver abuses it).

You decide if the priority is power or conservatism with your foot, and by talking to your tuner about what you want out of the tune.
Although I'd avoid it, there's such things as hypermiler tunes, for example. Do your due diligence and find a tuner who will listen to what you want out of it.
If you settle for a canned tune, yea, tradeoffs, because those don't bother with anything that isn't instantly obvious all the time and cater to stereotypes.

Hey, if you want the LQ9 to last a bit longer, feel free to ask the tuner for WOT upshifts 100-250RpM SOONER than GM OE.
Let's say you always tow / haul near the spec limit. You can have the Tow / Haul shift table improved.

In my case I had my Normal shift table programmed to slightly discourage me from driving like an @$$ (WOT upshifts happen 250RPM under OE spec),
while tuning my Tow / Haul shift table more like a Performance mode, since I'll never tow anything with it - helps when I drive Mom to hospital.
Although it took a bit of doing, I even got my tuner to tune 'Hot Mode' to come on far sooner than GM OE.
When my Tahoe was about to overheat (230F), the engine and transmission started running very differently, keeping a bit cooler (2 electric fans help too),
which gave me another precious minute to avoid making a traffic jam worse before pulling over @ 239F.

 

[99Sierra2500]

Someone the other day said theirs sounded like the engine was going to explode when they were towing a trailer. It's like huh.

 

[AuroraGirl]

No offense taken in fact I'm happy to have my years long hunch confirmed and it great detail! I appreciate the advice and I'll absolutely take it to heart! In my shade-tree mechanic common sense mind I always thought tuning stock would have to help but never looked into it because I'm new to tuning in general and to the Houston area and not sure where I could go to have someone take my "stock tuning" idea seriously and fear of getting scammed on someone not really doing much to it. As a kid I always dreamed of having the 800's so I drive them easy, but I would love to feel a little more performance sometimes when pulling trailers or just playing a little. Also really intrested in the gains in durability and longevity as I plan to keep these forever! Yukon first cause it'll wake the 5.3 up a lot? Also excited for the 6.0's as I really love them and I always wondered how they'd respond. Only had the LBZ a few months and I already love it and now want another Duramax in the fleet lol. I'll give them the a little foot from time to time but I'm much more conservative to keep all these in good shape for the long haul! Any ideas on tuners in the Houston area or is sending the PCM's off to someone a good option or would they benifit most from an "in shop" dyno tune to tweak each of them optimally? And any advice or any specifics to ask my tuner about or what to ask for to get the most out of what I'm looking to get out of it? Thanks so much for your time and the detail!

You have 2 vortec max? Engines ?

 

[AuroraGirl]

Decreasing Power Enrichment delay only results in less fuel economy if the driver 'takes advantage'.
However, the prime purpose of Power Enrichment is cylinder cooling at sustained high loads, not more power -
GM's PE AFR is a bit too rich to make much more power - 'more drivetrain wear' doesn't apply to the engine.
Making the PE AFR slightly less rich than GM OE spec actually improves fuel economy while making more power, when the driver so chooses.
As for the 4L60E, carefully revised line pressure and shift time adjustments minimize drivetrain wear better than GM OE in certain cases -
especially in the case of the LQ9 (again, unless the driver abuses it).

You decide if the priority is power or conservatism with your foot, and by talking to your tuner about what you want out of the tune.
Although I'd avoid it, there's such things as hypermiler tunes, for example. Do your due diligence and find a tuner who will listen to what you want out of it.
If you settle for a canned tune, yea, tradeoffs, because those don't bother with anything that isn't instantly obvious all the time and cater to stereotypes.

Hey, if you want the LQ9 to last a bit longer, feel free to ask the tuner for WOT upshifts 100-250RpM SOONER than GM OE.
Let's say you always tow / haul near the spec limit. You can have the Tow / Haul shift table improved.

In my case I had my Normal shift table programmed to slightly discourage me from driving like an @$$ (WOT upshifts happen 250RPM under OE spec),
while tuning my Tow / Haul shift table more like a Performance mode, since I'll never tow anything with it - helps when I drive Mom to hospital.
Although it took a bit of doing, I even got my tuner to tune 'Hot Mode' to come on far sooner than GM OE.
When my Tahoe was about to overheat (230F), the engine and transmission started running very differently, keeping a bit cooler (2 electric fans help too),
which gave me another precious minute to avoid making a traffic jam worse before pulling over @ 239F.

The transmission and engine both behave differently when approaching overheat and once you’re at “overheat”

And two bits on factory limits.
Torque management is to keep you from money shifting the transmission, esp in 4l60e or fwd 4t65e

Then things like delay in throttle input for throttle sensor/vs cable throttles, other limits to increase fuel economy or make the thing more driver friendly for average person

 

[Marky Dissod]

I'm new to tuning in general and to the Houston area and not sure where I could go to have someone take my "stock tuning" idea seriously
and fear of getting scammed on someone not really doing much to it. As a kid I always dreamed of having the 800's so I drive them easy,
but I would love to feel a little more performance sometimes when pulling trailers or just playing a little.

So, that'd be when your foot is past 33% TPS? 50% TPS? GM definitely made things very conservative unresponsive and discouraging under 50% TPS.

Also really interested in durability and longevity gains as I plan to keep these forever! Yukon first cause it'll wake the 5.3L up a lot?

Depending on how you normally drive the 5.3L, yes, even the Normal shift table can be made to better suit your specific tastes.
If you've the sense to avoid treating your 5.3L like you wish it were a 6.0L, yes, durability and longevity can be improved.

Also excited for the 6.0L's as I really love them and I always wondered how they'd respond.

If you so choose, it'll be painfully obvious that GM was holding back. Or, you can have them tuned for preservation.
How do you want it? Yes, this assumes you find a tuner with the patience to listen and tailor your tune to suit you.

Only had the LBZ a few months and I already love it, and now want another Duramax in the fleet lol. I'll give them the a little foot from time to time,
but I'm much more conservative to keep all these in good shape for the long haul!
Any ideas on tuners in the Houston area or is sending the PCM's off to someone a good option?
or would they benefit most from an "in shop" dyno tune to tweak each of them optimally?
And any advice or any specifics to ask my tuner about or what to ask for to get the most out of what I'm looking to get out of it? Thanks so much for your time and the detail!

I personally recommend sending off pcms to PCMperformance.com (see my sig). TYF tends to recommend BlackBear.
There are other reputable tuners out there who will show you how GM held out on you.

The transmission and engine both behave differently when approaching overheat and once you’re at “overheat”

My tune has 'approaching overheat' and 'overheating' set much lower than GM OE, and I'm so glad I did.

To be corny, I even adjusted the fuel level displayed so that it says I've slightly LESS gas in the tank than actual. (I also set my clock fast for similar reasons.)

 

[AuroraGirl]

So, that'd be when your foot is past 33% TPS? 50% TPS? GM definitely made things very conservative unresponsive and discouraging under 50% TPS.

Depending on how you normally drive the 5.3L, yes, even the Normal shift table can be made to better suit your specific tastes.
If you've the sense to avoid treating your 5.3L like you wish it were a 6.0L, yes, durability and longevity can be improved.

If you so choose, it'll be painfully obvious that GM was holding back. Or, you can have them tuned for preservation.
How do you want it? Yes, this assumes you find a tuner with the patience to listen and tailor your tune to suit you.

I personally recommend sending off pcms to PCMperformance.com (see my sig). TYF tends to recommend BlackBear.
There are other reputable tuners out there who will show you how GM held out on you.

My tune has 'approaching overheat' and 'overheating' set much lower than GM OE, and I'm so glad I did.

To be corny, I even adjusted the fuel level displayed so that it says I've slightly LESS gas in the tank than actual. (I also set my clock fast for similar reasons.)

Would you say the stock lq4 with throttle by wire not cable slight hesitation from a stop on the brake is built into the tune(so having the delay removed will help it) or is a condition of something else?

 

[99Sierra2500]

Would you say the stock lq4 with throttle by wire not cable slight hesitation from a stop on the brake is built into the tune(so having the delay removed will help it) or is a condition of something else?

Sure its not the serial communication protocol?

 

[AuroraGirl]

Sure its not the serial communication protocol?

Wdym?

 

[Marky Dissod]

Would you say the stock lq4 with throttle by wire (not cable) slight hesitation from a stop on the brake is built into the tune (so having the delay removed will help it)?
or is a condition of something else?

I don't tune GMT800s yet, so I can't say for sure yet, but I'd not be surprised to learn that GM slowed & dampened electronic throttle response;
if that's the case, the delay does not have to be 'removed' entirely - it's another parameter that can be considerably tailored.

 

[99Sierra2500]

Prior to bosch canbus as the standard, GM used a 10kB signal that I have heard was subject to log jamming, so it had a delay to help prevent that.

On-board diagnostics - Wikipedia

en.wikipedia.org

 

[CPB]

That's a great point man I appreciate that! I drive mine pretty easy but like to mash the gas every now and again. Mostly though I'd like to just make them run better but also make them last longer too kind of a balance of everything. I'm not looking for most power possible to the point of putting longevity at risk unless it like... Hey here's all the power you can get just don't beat on hard every day and you'll be fine they I'll be fine cause I grandpa them around more than anything lol.

You'll enjoy what most tuners are doing. Increasing shift pressures, shift timing and allowing PE to kick in sooner.

Without PE the vehicle runs in closed loop, 14.7 as the target AFR and the according amount of timing. So it's pretty restricted, meets emissions and limits torque output to the transmission. It's why you'll hear people talking about how night and day removing those limitations from GM transforms the vehicle.

There's no free lunch and we all have different goals. On a truck I'm using stock PE delay. On my car, it's setup very differently

 

[AuroraGirl]

Prior to bosch canbus as the standard, GM used a 10kB signal that I have heard was subject to log jamming, so it had a delay to help prevent that.

On-board diagnostics - Wikipedia

en.wikipedia.org

Interesting. Wonder how to read more abouT this

 

[Gavin]

Why do you want to do a burnout?

Why wouldn’t I want to is the real question

 

[Gavin]

i feel like youre going to break an axle shaft in a 8.6 10bolt rear with a 4.30 or larger ratio and doing burn outs, maybe im wrong but im suspecting the twisting is gonna strain it

Definitely wouldn’t doubt it