I'd like to know if the stock '04 RSX TypeS psuedo wideband 02 sensor is suitable for tuning a supercharged engine running E85? It was recommended to use the stock sensor since it is wideband and the ECU is a PRB K-series one, so...sort of plug and play.

I ask because I've read that AFR's for E85 should be down in the 9.5 range, and perhaps even a little richer if supercharged.

I've also read that the stock 02 sensor for the 04 RSX, while called wideband, only reads down to about 11.7.

Yet, I was told that it should be suitable.

What do you experienced guys think?

Car is a MY04 S2000 running Doctronic ECU (similar to KPro using '04 RSX TypeS)

 

No, in my experience, the factory WB02 is fine near stoich, but below 12.x it is supper inaccurate (like a point plus off). I log factory WB02 and my Bosch 4.9. I'd never use the factory to tune.

$0.02