AFM / DOD DELETE KIT
Parts & Installed
We offer the INSTALLATION of Texas Speed & Performance AFM / DOD Delete Kit and the required Non AFM / DOD camshaft.
- New GM MLS Head Gaskets
- New GM Head Bolts
- ALL New 16 Delphi LS7 Style Lifters
- New GM 12625437 Non AFM / DOD Camshaft
- New GM VVT Cam Phaser Valve / Bolt
- New LS7 Lifter Guides
- New LS7 Style Non AFM / DOD Valley Cover
- New Timing Chain Gasket, Water Pump Gasket, Etc.
This is a very labor intensive upgrade. IMO if considering this AFM / DOD delete option you might as well go with an upgraded camshaft like the Texas Speed Stage III VVT cam. When doing this modification / delete kit the factory AFM / DOD cam needs to be replaced with a Non AFM / DOD camshaft anyhow. If not, cylinders 1, 7, 4, & 6 will be low on compression and an idle misfire will occur. This modification is most economical and of course manditory when upgrading to an aftermarket camshaft like the Stage III VVT Cam. But doing this modification by itself is quite expensive with NO performance gains, only piece of mind for future and long term reliability.
AFM / DOD Info
Active Fuel Management / Displacement On Demad
The Active Fuel Management (AFM) or also known as Displacement On Demand (DOD) system first was introduced in the GenIV Vortec engines in 2007. Not all Vortec's had this system in what I refer to as the first generation of GenIV (2007-2009). By 2010 I believe ALL Vortec's had AFM / DOD and is what I refer to as the second generation GenIV (2010-2014). Under certain driving conditions, primarily light load cruise, the ECM will deactivate 4 cylinders (1,7,4,6 cylinders) and essentially run the V8 in V4 mode. This system is for increasing fuel economy. Although the concept has been around for awhile, it adds complexity to the mechanical components of the engine and some known issues / problems have been documented over the years.
For a detailed explanation of how the system works you can scroll down. We offer an AFM / DOD MECHANICAL delete option on any GenIV engine that came with it. The AFM / DOD system fails when the lifters don't return to their extended (normal) length. Our default is to electronically DEACTIVATE AFM / DOD in the ECM for any GenIV engine as the phylosophy is: If the engine is currently operating properly, if you don't allow the lifter to collapse in the first place you won't ever have a problem with it extending back to V8 mode. This default "deactivation" has proved to be a viable option, but for absolute assurance deleting the system mechanically and replacing the potential problem 8 AFM / DOD lifters is the best choice.
AFM / DOD Operation & Failure Details
(Information here is compiled from various online forums, Lt1swap.com, etc.)
For the lifter to go into V4 mode, oil is pumped into the lower groove (nearest the roller) When the lifter is sitting on base circle, the spring in the lifter is trying to push the two parts apart, when oil pressure is introduced, the pins in the inner lifter part do not immediately go inward. The opening ramp on the cam lobe has a what i'm going to call a ''lash ramp'' to say similar to how a solid lifter cam works. This small ''lash ramp'' takes the pressure off the pins long enough for hydraulic force to push them inward, than the lifter starts riding up the opening lobe ramp, and the inner part of lifter goes downward for V4 Mode. Cylinders 1,7 4,6 are designed to shut down, and therefore those lobes of the cam have this ramp for the AFM lifter to function correctly.
To my knowledge there are 3 lifter designs from GM. Lower is factory original out of a 2007. Upper is a replacement GM Lifter with about 5,000 miles on it before it locked down.
It appears what causes the lifter to lock down, is metal debris from the pins constantly catching in the groove they are meant to be in when in v8 mode. When lifter goes into V4 mode, the metal causes the inner/outer portion to bind up.