i've posted this on another thread: is it just me or do i get better mileage from normal premium as opposed to ultimate?? im 99.9 percent sure i have a stock ecu ... have hi flow air filter ... decent aftermarket exhaust ... i get 300-350 on ultimate and 400-450 on normal premuim ... why is that?? .. and my cars an automatic ... r33 gtst.?? i've even tried normal unleaded ... but i think i would get about 300kms per tank cause i didn't fill up all the way, just seeing what the performance was. anyone got any ideas?? i'll just stick to normal permium now cause it comes out cheaper both ways. i've even tried woolworths premium and it gives me about the same mileage but i still think that normal premium (BP that is) gives me a better idle .. but i think i can feel more power with the ultimate.
thanks