I got a pocket programmer for a xmas present.
I have created my first copy bins and am using tunerpro to compare them. Anyone else with a 1228746 ecu $61 can find them here.

1228746 ECU File

Stock 91 5.0 TBI LO3 F Body Auto 2.73Rear

Aftermarket Performance chip

I notice a huge difference in ignition timing (initial is bumped up to 4.5 degrees and the main table is quite different) so should i start tuning my car using the original or the modded ?

ALSO

During datalogging I noticed that the IAT with stock air cleaner and thermac etc averaged high30s-low40s Degrees with a high of 64Degrees after a prolonged idle !
I removed the filter lid and filter and ran same stretch of road, IAT temps lowered to mid 20s with a low of 18 and an at idle high of 39.
As cooler air=denser air=more Oxygen=ability to burn more fuel how can i maximize the advantages from this change ?

 

Start with the stock stuff, go slow, and keep meticulous notes.
You need to look and see what the IAT temps are used for, before assuming you can capitialize on it.
GM is not to be underestimated for how clever they are. If you disable the Thermac setup you'll lower the temp range below what the code assumes it would be.

Cooler air, also means cooler fuel, and less vaporization. Less vaporization, means the harder the fuel is to light. There is a downside to ever clever up side, so thing need to be considered from all sides.

Not trying to be negative, just mentioning the other side.

Also, by using a stocker, your not basing your work on possible errors of others. There are alot of folks that think tuning to the max timing possible under all conditions is the best answer, when in fact that's not universally true.

 

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You need to look and see what the IAT temps are used for, before assuming you can capitialize on it.
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Where do i look for this ?
I normally trawl through tunercat and tunerpro trying to make sense of the constants / tables and graphs and how they relate to the various ecu input/outputs. is this the wrong place ?


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Cooler air, also means cooler fuel, and less vaporization. Less vaporization, means the harder the fuel is to light. There is a downside to ever clever up side, so thing need to be considered from all sides.
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Do you have an intercooler on that little V6 ?
The point i am trying to make is that sometimes the upside is greater than the downside.
I will G Tech and let you know if the Terminal speed goes up.
I will be trying to get the intake air temp to a constant and ideal temp, when i had a turbo car the general rule was that the intake charge should be no more than 30 degrees and if possible maintain that even during the initial turbo spike and under prolonged load.
When i saw a max as 64 i kinda thought that was a bit much, I am maybe paying to much attention to intake temps cos of my turbo days.

 

Yes, you have to look thru the variable in the tuning section, of what ever editor you have. And finding a comented hac is also a worthwhile thing to do so you can see if there is some less used stuff that you want to use.

Nope, the I/C fell off my car some time ago. For what I do, and the mods I've had it's faster without it. The universal truths are correct for as far as they go, but there are other things to consider, like with an I/C, when not in boost conditions what does it do?, how long does it take to recover from the thermal loading from having been in boost, weight, pressure lost, there are a bunch of other items that need to be considered when making changes. There are always up and down sides, doing something without thinking of the whole package, can lead to erratic if not actually poor results, for a given application.