EGR Delete OBD1 1994 Corvette

[lesman]

If I start out fresh. What settings do I need to tweak to bring my octane rating up to 93 or 91 minimum?
The default settings from factory has been usually 89 octane. Are the bins set at factory or do they have the higher octane rating applied?

[NomakeWan]

First, an 8051 will work fine in a Vette as long as it has a Vette BIN. kur4o found that address 3AC7 controls whether the PCM tries to be a bus master (such as on F-Body cars) or let a CCM/BCM be a bus master (such as in a Corvette). The latter sets all values to 0.

As for octane, "octane" is not a setting. It's not some magic thing you can just one-click to change. The minimum required octane for your engine depends on several factors that boil down to cylinder temperature and cylinder pressure. Here's some info: http://www.gearhead-efi.com/Fuel-Inj...ll=1#post97660

In short, GM gave the owner's manual its recommendation based on internal testing and lowest-common-denominator philosophy. The PCM also has a Low Octane Compensation mode that retards timing if too much knock is encountered (at least, that's how I assume it works, based on similar compensation techniques from other manufacturers of the era I am familiar with). So if you follow GM's owner's manual recommendation, you'll get what's advertised. If you use 87, you won't get all the performance advertised, but GM will stop you from destroying your engine.

Once you start tuning things for your specific engine, you are now in no-man's land. No one knows your parameters but you. So whether you need to put higher octane fuel in or not depends entirely on your engine configuration as well as your tune.

As a side note, in case you were curious, Hypertech didn't know what octane would be required either--they just gave a blanket recommendation so as to avoid potential lawsuits. Considering how dumb their changes to the tune are, that was probably prudent.

[steveo]

If I start out fresh. What settings do I need to tweak to bring my octane rating up to 93 or 91 minimum?
The default settings from factory has been usually 89 octane. Are the bins set at factory or do they have the higher octane rating applied?

higher octane needs more timing advance to burn completely. so the setting you need to tweak is your timing tables