I have an 93 LT1 Y Body with 396LT1. I was reading the impala forums and saw that they get better gas mileage after retuning their DFCO section after modifying the engine. I have logs, but just dont get what needs to be changed to allow the engine to go into DFCO to allow better fuel economy while letting off the throttle etc.
I know what the setting do, but I am sure there is a way they need to compliment each other to accomplish better fuel economy.

 

I've played with $6E & $32B's DFCO settings quite a bit and I can say that you really can't activate it too often, it's up to your own tolerance. Basically you want it to activate as soon as possible for as long as possible. You can set it up to activate like crazy every time you slow down or lift the gas a little and save fuel but it'll drive you nuts because it can engage at some of the most inopportune moments, like stop and go traffic. You need to find the right balance where it only activates when you want it to. I don't know how it operates w/ LT1 stuff but I eliminated load based triggering and use rpm & delta throttle to activate it. Min time to activate is .35 sec. Also set your time limit high to keep it active as long as possible. You can play with the time between consecutive DFCO's setting to make it a little more driveable. I have mine set up in a way that if I tap the brake at the right moment coasting downhill it'll kill the motor for the whole decent.

 

Kill...??? elaborate please

 

Decel Fuel Cut Off

 

How does tapping the brake kill the motor with regards to how you set up your DFCO?

 

Ah, sorry. I'm not entirely certain if it's part of $6E's algorithim or not because it didn't do that with $32B, but DFCO will activate often when I press the brakes. I had to extend the time limit to keep it active throughout the decent and change the rpm window a bit (1200 on to 1000 off). Above a certain speed (about 40) the converter's pulling enough to keep the motor turning above 1000rpm.