In Reply to: Without exception..... posted by bmv on February 10, 2000 at 10:44:28:
"Did you measure, in real time!, the air-fuel mix inside the combustion chamber."
Nope, I just checked it through the exhaust using the O2 sensors... the same way the DME will.
"What were the results?"
Pre-blower with stock software my first 02 output was around 0.8v at WOT. This is around a 13.5/1 AFR. Good but not quite rich enough for maximum power.
Post-blower my first 02 sensors output is around 0.9v at WOT under full boost. This is around a 12.5/1 AFR. This is just about perfect for maximum power.
"has had to modify his fuel delivery system. "
We all had to modify it somewhat with the boost sensitive fuel pressure regulator. As boost rises the fuel rails pressure increases which makes the injectors squirt in more fuel for any given open time.
Karl decided he wanted to get rid of that extra regulator so he replaced it with larger injectors and a SplitSec controller box to trick the DME into giving him the correct amount of fuel.
"what are the precise post-SC octane requirements."
The Downing is 93 or higher with the factory DME software.