7427 Rev limiter / 4L80E question

[dubwise]

Yes getting the '7427 to datalog WBO2, and run your 4L80E is relatively easy. To answer your questions:

1. You should have no problem using that '7427 to run the 4L80E. Just make sure it has a memcal with a chip with a $0E .bin burned onto it. I don't know if a V8 memcal is mandatory, as there are no fuel or timing outputs being used. But you should probably spend some time disabling any DTC's that you don't need. For datalogging and .bin editing be sure so use a $0E .xdf.

2. Doing the above should provide you with all the parameters you need to tweak the 4L80E to your liking. Most all of the trans stuff is near the bottom of the Constants, and Tables sections. Attached is the .xdf that 93V8S10 made long ago, and I added few features to, I use it for both of my TBI vehicles.

3. Anything out there that is "optimized", wont be optimized for your engine, gear ratio, or vehicle.

4. I don't believe that feature exists for the '7427.

Thanks!!

i seem to remember seeing both code references and maybe even a diagram or two of a "manual, normal, perfomance" shift pattern switch.... i'll have to look around to be sure.

That would be awesome if you could find this. Please let me know if you do.

I'll put in a couple.
In regards to the 4L80-E:
If you wish to have ONE PCM or controller, you can. Since you have a 92 with the older BOSCH force Motor controls, you can move to the Holley Force Motor Controls BUT YOU MUST replace the Valvebody assembly (with aux valvebody) and Force Motor.
The rule with the 4L80-E is to keep the Force Motor, Valvebody, space plate, and TCM/PCM as a UNIT. If you want to know why I can respond.
In order to move your 92 TRUCK to the 94-96PCM controls I would suggest you replace the valve body, spacer plate, VB gaskets, and I would replace the internal and splice in an external trans harness WITH the PCM. If this were mine with a 540 cu in, I would HIGHLY SUGGEST you seek out a BIG BLOCK Valvebody. These Vavlebodies had a higher GAIN in Line Pressure and is better selected to control the higher power. I would suggest you enlarge or remove the checkballs for the direct clutch circuit that is for 3rd gear. I would suggest you enlarge the 2nd gear FEED hole in the spacer plate. One CRITICAL ITEM is you BEGIN WITH A CALIBRATION or FILE or BIN that is set up for a 4L80-E and NOT try to make the calibration into one. In the definition file there are MISSING BITS AND CALIBRATIONS that are NOT defined in the XDF file. In plain there are things you cannot see or change in the cal you need to in most cases. How I know this is this was my job @ GM.

All good info. Thank you. Can you elaborate on why its a good idea to replace the force motor valvebody, space plate with this PCM swap? The 92 454ss came stock w/the 4L80E, so I would assume it already has the Big block valve body..?? The last thing I want to do is ruin the trans by doing this swap.

The XDF or Definitions has some trans calibrations. Wide OpenThrottle functions like this:
There are calibrations for WOT or it is called KICKDOWN HI and Lo. It works like this. Once the TPS crosses this Kickdown Hi, the shift pattern looks at the KICKDOWN for the given commanded gear to UP or Downshift the trans. It does NOT look at the Tables. Each calibrator, well most of us, always set the tables the same as the Kickdown so when we looked at our shift lines in Excel spreadsheets it was the same and the best for us to observe/correct/suggest changes. Now, as soon as the TPS crosses the Kickdown LO TPS cal, the shifting resorts back to the tables.

I think I understand this but I want to make sure. What you are saying is that when TPS >= "TPS to Enable Kickdown", it resorts to the "Kickdown" tables, otherwise it uses the "Normal Mode" shift tables, correct?

It looks like the 7427 bins do not use "Upshift RPM vs Shift" as they are all zero'd out. This is whats confusing me. Is there a way to enable/utilize this table or do I need to calculate the RPM limiter as a function of MPH..? ie: based off trans gears/ gear ratio/ tire size etc..and then output the results to "Upshift MPH vs Shift" .. ?

I found "RPM to Enter Fuel Cutoff" but since I'm no longer using TBI to control fueling this is useless.


Thanks again for the responses guys!!