thanks for the explanation but this confuses me a little then
"The standard "blending octane value" for ethanol is about 113. Normally one litre of ethanol blended with 9 litres of petro-gas raises the octane of the 10-litre blend to the next grade level. For instance after blending 9 litres of petro-gas with one litre of ethanol, Regular Unleaded (87 octane) becomes Unleaded Plus (89-90 octane) and Unleaded Plus becomes Premium (91
+ octane)."
http://www.gov.mb.ca/est/energy/ethanol/ethanolfaq.html
anyway it's not that important to me ... i just just curious. thanks!