this is retarded. lt1 edit i buy this theres no documentation on what does what, you have to pretty much guess because theres no way to research most of the stuff or its not discussed. Like how to setup your shift points , does this involve the kickdown rpm, when messing with the engine do you put in your cylinder size in cubic inches or leave it alone i have a 383 do i put in 47.875 vs. the 44? What does what, theres not even a damn good guide out there , basicly ive seen every availible site and its nothing but a simple over view and alot of times people still dont know whats what. Its just frustrating, i mean anything else i want to know i can find out about but yet we keep the pcm stuff a big secret it seems like.

 

The PCM is a very complex computer with a huge number of parameters that can be modified. I'd guess the tuning community only knows a portion of them, which is represented in tuning packages like LT1EDIT.

My personal experiences in learning how to tune PCMs involved a lot of reading, Googling, and experimentation. I've probably flashed my PCM a couple hundred times now trying different things, then driving the car to see how the car was impacted.

Now, for your questions... Bear with me here, I'm using TunerCat so the table names might be a little different. Shift points are determined by two different tables - Normal Up/Down shift points, and the Kickdown shift points. Kickdown mode is activated when the TPS % threshold is passed (I believe by default it is set to about 93%). Until your throttle position reaches this threshold the normal shift tables are in effect. Otherwise the PCM uses the kickdown tables to decide your shift point.

Regarding engine size, I've seen some PCM tuners change this, and others leave it alone. I think it makes sense to set it correctly for your engine size because the PCM uses this value to calculate how much fuel will be needed. Your 383 will require more fuel then a 350 would. But, you could technically account for this extra fuel in other places, too, like in the injector offset, or VE tables.

What other values are you interested in knowing about? Or maybe I should ask a more elemental question - what are you trying to accomplish?

 

basicly im just wanting to know how to tune/modify the little things first, then ill work on fuel timing ect. i was just going to change the idle speed, and i seen the cylinder displacement so i changed it. Then i wanted to get past my 30mph 1st gear drop so i wanted to extend it to about 36mph just change my shifts around alittle for my cam. Like I said pretty much right now im just wanting to figure or get an idea on whats what and then maybe make small changes to see what does what. Start out small ( Shift points, idle speed ) Then get to (timing, advance, fueling) thats all. Thanks for you help so far.

 

For the shift points, take a look at my article at http://www.trifectaperformance.com/t...rmanceMode.htm in the "How it Works" section. It talks about how upshift and downshift works.

The PCM determines what the idle speed is based on the coolant temperature. For example, if you want to raise your idle speed, say, 50RPM, just add 50 to all of the values in the idle speed table. For any given coolant temperature, your car will idle 50 RPM higher then it would have stock.

 

On Carputing's site there's this:

http://carputing.tripod.com/AKM_lt1netfiles/LT1Edit.htm

It's as close as you'll get for a how to manual for LT1 Edit.
Worth reading to get a start on things.
Make sure you save your original file before making changes.

 

There are some aspects for which there is little or no information out there, but the very basic things you mention are extremely well documented. I think that if you can't figure out how to find / understand the info out there, you're better off paying somebody to tune the car. If you just start changing things without understanding, you're likely to damage something.

 

So I checked your old threads and two days earlier you posted:

That's a great attitude. What happened to it?

Is 2 days your idea of a reasonable time investment ? You can't possibly have read much of the available information on LT1 tuning in 2 days. I've been searching and reading for 3.5 years, and I haven't remotely seen it all.

My suggestion is to start by googling "LT1 tuning." There are several good tutorials on the web that will get you started.

 

Vince- Thank you SOOO much for that link! Ive been looking for something like that for about 2 weeks.. I hope it will get me where I need to be..

Jeff