Quote:
Originally Posted by kokopellimotorsports
Cody,
You could get into "why" for me and I am sure allot of other people on this forum. I read your stuff on the sniper forum and found it very helpful. As I posted in another thread I want to get my tech section of my website built up, so anything you want to write about would be great for me. Hopefully you will let me use it on my website.
Ty
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Ty,
Sure thing, man. It comes out of my head and there's no copyright on it, so feel free to use it.
Why a fueling-box style module is a bad thing for a E4OD/4R100:
The factory programming is set up for a specific torque input into the transmission. The programmers spent a lot of money to get the accelerator pedal position (APP), EPC (electronic pressure control) system ("line pressure"), shift speed calibrations, etc. just right so that maximum life expectancy was achieved.
Aftermarket programming is one thing...it can take into account the increased power output of the engine for a given APP. This helps the shift duration feel stock or firm depending on torque input. Also, the road speed at which the shift occurs can be altered for a given APP.
When a fueling box is added to the 7.3L PSD, the sensor input to the PCM for injection pressure is corrupt. Essentially, the PCM "sees" a lower pressure than what is actually there. The Ford PCM programming allows it to command a higher injection pressure regulator (IPR) duty cycle to increase the pressure output of the high pressure oil pump to what is desired, even though the pressure is actually good. This raised injection pressure has an effect on a few tuning variables in the PCM, but the power increases caused by it are not applied to the transmission shifting parameters.
The higher injection pressures will cause a more responsive accelerator pedal. This means that for any given engine speed or load, the APP voltage input to the PCM will be lower. The PCM bases it's EPC, shift scheduling, and calculated torque on APP (indirectly through MFD or "mass fuel desired"). So, the PCM thinks the actual engine torque is lower than stock for any given accelerator pedal input even though the opposite is true.
More power with earlier/softer shifts and lower line pressure equals bad news. Some folks can run around with these devices and have no problems....it all depends on driving style. They are not something that should be used for heavy towing or racing. Yes, they operate as designed and usually add a couple MPG. They work well, but are better suited to manual transmission trucks.
I hope this helps a bit.
EDIT:
By fueling box, I am talking about the Edge Juice, Banks 6-gun, Dr. Performance/Workhorse, Dfuser 18K, etc.