Does the ECU lower the overboost control , when lower octane fuel is used. I have 94WRX runs 95RON and overboosts at 0.8Bar . I dont think its a faulty solenoid , but wonder whether the ECU lowers the overboost protection ???

 

don't use 95 ron-it'll cause detonation and seriously kill your car. ALWAYS use super as it's closer to the ecu map of 100 ron as per jap petrol. do a search for further on octane boosters, broquets etc but dont use 95!!!!

 

Standard boost is 0.9bar on the early cars, Overboost ... what is it holding ? Running on 95 ron means the ecu will be in full retard ignition mode, once it hits the stops it may then drop boost to try and compensate further but .... 95 ron will hurt your engine, if you can get nothing else then use booster as well but don't use 95 on its own. Play safe ... don't take risks ... its one of the penalty's of owning a Japanese spec car.