I want to know if you can run E85 in a lean burn motor? What problems can I run into with the fuel system? Will it hurt the 5 wire o2? How much can i run?
With the old motor b18c1 turbo (4-5 PSI) I would run 4gal. of E85 and the rest 91 and had no problems with it. I have a lot of 4 wire o2's and injectors in case they wore out early.
More than anything you need to ask yourself if the oem injectors and fuel pump can handle the increased supply that your altered fuel map will need to call for. A lot of turbo honda guys are running e85 but pay a pretty penny for the way larger pump, injectors, and injector driver.
I think about how SuspendedHatch found a tuner that could share his vision of a FE car. You'll need to do the same. A lot of people say that the octane rating of E85 is equivalent to 100 octane so in theory you can run a slightly leaner burn too but a competent tuner will need to determine a safe a/f ratio, as well as advice on what size injectors and pump will suffice.