Hey,
So Ive been reading up on tuning a lt1 and ive been playing with my software...not actually hooked up to the car....but I would like to try and see if I can tune it. But I was wondering if anyone is familar with lt1 edit, cause i was wondering is there a ser value that you want to try and achieve in each cell block....long and short term fuel...how do ya know whats best without putting it on a dyno. Are their default number that are good for a high modded lt1? if you know by your data logs what the engine is doing and you just want to clean up a few thing how do ya know how much to change the values and how do you know that the value is good or bad. I have always built all my own cars myself and they were all carbed ...it kills my to be clueless...i just gotta learn this...lol

 

Well to begin with, everything is analogous to a carbed car, but you have more power to get it to do what you want without the restriction of mechanical actuators like timing weights and springs and fuel jets and accelerator pumps.

But basically, you have closed loop operation once it warms up and it is taking direction from the oxygen sensors, temp sensors, MAF sensor, MAP sensor, and timing tables based on throttle opening, rpm, etc. to get you where you want to go. So there are a lot of tables used for reference based on all the environmental factors and inputs from sensors trying interpret what the driver is trying to get his vehicle to do, and all the while trying to remain emissions compliant, get good mileage, and provide adequate performance.

But in answer to your questions, basically, when in closed loop, you need to make sure it stays near 128 for LT and ST trims because 128 is neutral - it is the middle of the adjustment for your fueling. You may need to adjust your injector turn on times if your idle is rich or lean and if your fuel across the board is rich or lean, you can adjust your injector constant and if it is up and down, you can adjust your MAF calibration to cram it in a little tighter. Before you do any of this, make damn sure you don't have any intake or exhaust leaks anywhere before or near the O2 sensors or any mechanical problems or misfiring cylinders or you will be chasing your BLMs all over the place and nothing will make sense. For WOT, you have extra fueling enrichment based on temp and rpm and you can adjust that to whatever mixture you want as long you have some way to measure it. It's a known fact the stock tune is rich in the fat part of the torque curve to protect the engine and you can find some power by leaning that part out a little bit, but don't go too far. You have logging tools which will help you see your changing rate of speed and you can use those to measure your performance if there's no other way (dyno or track) and you can also see what your ignition is doing regarding timing retard, etc. and use that as feedback for your adjustments. Narrow band sensor readings are marginally useful for WOT fueling, but a wide band is a far better tool for someone tuning his fuel mixture.

It ain't no big thing, any chimp can do it, LOL.