After answering a quick question at:https://www.celicahobby.com/forums/...5/best-automatic-transmission-fluid.html
Source: The owner's manual that comes with all new Toyota Celica
I decided to check under what it also says should be used for "FUEL"
NOTE: The above image is from the 2000 Celica Owner's Manual. The below quote is from the 2001 Celica Owner's Manual, which includes few minor revisions (mostly grammar and spelling corrections). The specifications between the two are identical, though year 2000 manual states "Octane Rating of 95" and the year 2001 manual states "Octane Rating of 91" for the 2ZZ-GE engine (Celica GTS) - which is an obvious correction. It's also assumed that there is no difference in manuals between a "North American sold" Celica and those sold outside of that continent other than the obvious use of the different localized language. The tag on the underside of your Celica's Hood
presumably also duplicates this suggested octane rating information of a "91" for all Celica 2ZZ-GE engine years.
Unleaded gasoline, Octane Rating 87 (Research Octane Number 91) or higher
Select premium unleaded gasoline with an Octane Rating of 91 (Research Octane Number 96) or higher for optimum engine performance
If using higher octane would get you better engine performance output -- Higher MPGs vs Lower idle via ECU, A cleaner 'spark' -- wouldn't a better performing engine mean that it also gives you a bit more on the Horse Power business end of things? What type of adjustments does the ECU make in this case?
What is the difference in HP gain that you can get from a 96 Octane fuel compared to the 91 octane fuel, which is commonly sold here in the USA? Is it really going to make that much of a hp difference over all or will it keep your engine running better over a longer period of time - although you might get a better spark or consume less fuel and make better MPG.
I'm sure you guys can see where I'm going with this. What exactly is involved in making a "180hp" USA (where 91 octane is tops at 90% of gas stations here) into a "NA 190hp" setup - such as those found in locations where 96 octane fuel can be found without a problem?
Whats really is the difference between a 180HP GTS and a 190HP GTS?