|
factory O2 sensor can only tell it if it's rich or lean, not HOW rich or HOW lean. meaning it would have to add in small increments to get the mixture right. that's fine for cruising, but you don't want it doing that when the ECU is in open loop under boost. granted, E85 can run pretty freekin lean under boost (i've seen 13:1 gas equiv and no signs of det on my car), but something that works the way you're describing would be too slow in real-time.
there are other kits that basically just take an injector pulse and add ~25% to it to make it run E85, but MR2s can run as high as 100% duty cycle, and you can't add duty cycle to 100%. add to that the fact that each injector is basically running 1 cycle behind where the ECU thinks it is.
neither is a good strategy. if you want to have flex-fuel capability on the stock ECU, your best bet is a fuel pump, an AFPR and a wideband.
|