I use 95RON Unleaded in my MY98 UK Impreza at the moment. As I live in Ireland 98RON SUL is virtually impossible to get. I am wondering would it be OK to add Millers Octane Booster to the petrol which should bring it up to 97RON. Would this be OK for the car and what sort of performance gains should I expect?

Cheers

Gavin

 

I think the answer here is to add it & see. I think the MY98 ECU is a 'slow learner'(?) so you may want to reset the ECU. Actually, you may want to reset it before adding the octane booster as well, just to make sure it's the booster that's making the difference & not just the reset!