LBZ: Raising Rev Limiter

Cougar281

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Sep 11, 2006
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St Louis, MO
I've done some reading and found a post on another forum by JoshH saying that modifying the following tables will increase the rev limiter on the LBZ's

B1125, Torque Limiting in 4WD Lo Mode
B1126, Torque Limiting in 4WD Hi Mode
B1130, TCM RPM Limiting
B1115, Pedal Position to Desired Torque
B1116, Pedal Position to Desired Torque (4WDLo)
B1102, Torque Based Fuel
B1117, Maximum Fuel Quantity vs RPM
B1118, Maximum Torque 1 vs RPM
B1119, Maximum Torque 2 vs RPM
B1128, Barometric Pressure Torque Limit
B1122, Torque Fuel Limit RPM Conversion
B1014, Pressure Maintain Fuel Limit

Going through the tune and comparing it to stock, B1125, B1126 & B1130 are the same as stock. The rest appear to have fueling all the way up.

If I have the transmission limited to 3rd gear (for pulling), will the TCM limit RPMs to 3250 or 3500 if I don't change these? Should I just change 1125, 1126 & 1130 can dall it a daty? I'd just like to make sure I won't be bouncing off the rev limiter in 4Lo & 3rd gear tomorrow night.
 

JoshH

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I have no idea whether or not those tables will limit RPM or cause a defuel, but I would change them just to make sure. If you don't want to change them, take the truck out and lock it in 3rd and run it up through the RPM while you datalog. See what that says.
 

Cougar281

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Sep 11, 2006
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Actually, that's more or less what I did... It'll run all the way up to 4000, but there was a slight hiccup passing through 3500 or so.... Looking at the logs, that was actually the Torque Converter locking.
 

JoshH

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I've also seen a "hiccup" at the same RPM where pilot injection shuts off (if you do that in your tune that is).
 

x MadMAX DIESEL

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Dec 30, 2008
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How do I make a rev limiter that wont let me hit 5000rpm? It doesnt sound very safe.. I can rev as high as I want right now it seems if I keep it in m.
 

JoshH

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I use B1118 to limit RPM. It has worked well for me.
 

x MadMAX DIESEL

<<<< No Horsepower
Dec 30, 2008
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Lexington, Ky
Will it bounce up and down and sound like its about to break, or stay there smooth? Just set 4800 rpm and up to 0, or should I set it just lower than max torque like 1250?
 

JoshH

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It has always been a smooth limit for me. Setting it to 0 should do the trick.