Duramax Diesels Forum Truck of the Week
Old 03-24-2020, 02:41 PM
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The numbers calculated are basically what I used when I had an LB7. I just had to calculate and add them manually. Took forever. At the time I couldn't figure out a way to make it work in excel until recently when another member asked if I can take another look at it.

It ran good in my truck and took care of the shift issues but the other tables are unlikely to be what your tables are so I don't know if it would work across all trucks. If my method is correct then it should. But I have no way of testing it now
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Old 03-25-2020, 01:24 PM
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I need to revisit LB7 and LLY defuel. I started chasing it in my IDA projects on how it actually is calculated. With all this corona nonsense going on, I just might find some time here soon just before L5P kidnaps me..... again

But with the things Ive learned over the years, there are alot of new techniques learned that involve the relationship of MM3 to Torque that is sorta a taboo in the duramax world as we have lacked the access to the necessary stuff.

But I will say, scaling out your MM3 and torque to the proper numbers DOES make the world of difference in how the truck runs and shifts... some ECMs have limitations on how high you can go (most are much much higher than what EFILive imposes on its users) but getting as close as possible helps a ton!

One thing I will say, there is a torque table in the TCM that isnt mapped that also plays a huge role in how the truck defuels. There is more AL5 coming opensource coming soon too. Obviously as I find spare time.

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Old 03-25-2020, 02:32 PM
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Old 03-26-2020, 05:53 AM
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Yngdmax92 Yngdmax92 is offline
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Originally Posted by Chevy1925 View Post
unless you know what you are playing with and understand the tables in great detail, its best to not mess with it. you can start killing the trans in a hurry if you just go shoving numbers in and testing it out in the truck.

WOT defuel is the one to really be careful on, part throttle is usually overly aggressive the moment you start adding in more power so there is room to mess with it IF you know what you are doing in there. small changes can make a BIG difference and you need to run the truck for a little while and log to see how it learns in.

Must be most tuners don't really mess with it? More or a personal thing. The tcm tunes I have purchased did not feel any different other then the simple raise the shift points at wot. Maybe idk. I guess I should of logged it before and after.
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Last edited by Yngdmax92; 03-26-2020 at 06:20 AM.
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Old 03-26-2020, 07:10 AM
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Originally Posted by Yngdmax92 View Post
Must be most tuners don't really mess with it? More or a personal thing. The tcm tunes I have purchased did not feel any different other then the simple raise the shift points at wot. Maybe idk. I guess I should of logged it before and after.
it just depends on who it is and what you have done. in most cases, you dont need to change it much, if at all. years ago, steve learned the tables really well and wanted me to try his defuel in my truck. made a big difference on larger injectors, stock injectors didnt really need it due to the way the tables work and what was adjusted in my tune. I know blake has got this dialed down now as well. It may not be good right off the bat but some logging and some tweaks can get you there. sitting in the truck is best to really make defuel work because everyone describes it differently.
Originally Posted by JoshH View Post
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Old 03-28-2020, 09:55 AM
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Originally Posted by 2004LB7 View Post
Here is some other calculators I have created with another member on here but haven't had anything to test them on. use at your own risk

The one I would most like feedback on is the defuel calculator for LB7 & LLYs. if anyone wants to try it out and give us your opinion I would appreciate it
I will see if I can create a simple 100HP tune using the defuel calculator for my 02 daily... The daily is stock other than a lift pump. I will keep you updated, my biggest thing is does anyone already have a awesome logging file for the LB7 that they wouldn't mind sharing?
"Race Truck": 2001 Single Cab Short Bed LB7 w/4L80E swap

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