i like this thread and at the same time not so much. like i said in some of my threads i run 104 octane since i rebuilt her just to baby my tc. the theory about harder starts and ruffer idle is true. but with our variable timing engines the ecu notice the differences in fuels and will adjust the timing. i cant say wether or not it makes more power but recently i ran out of 104 fuel so i just used 87 and it runs better at idle yet when i punch it it just doesn't feel the same. the reason i don't like this thread is because i have spent extra money for higher octane and your telling me it doesn't do nothing. you may be right but my tc seems to prefer higher octane at higher rpm. on a mustang dyno with 104 octain my car make 148 at the wheels and i will try to scrape up the cash to get one done with 87 to compare the difrences for y'all. the reason i like this thread because its coming from the facts of our tc and might prove me wrong and in that case i can save money .

 

Kicking a dead horse?

I started running 91-93 octane in my Corolla GT-S oh...a few years ago...

Car consistanly got 3-5 MPG more than with any other grade. I wasn't using bottom-of-the-barrel gas, either. Same in a Honda Accord. Same in a '95 Tercel. THat car got 4-6 MPG more on 91.

However, I have an '89 Mazda I use for work, and it likes 89, thank you. Consistant 32 MPG with 89.

I have been using 91-93 in the tC since I bought it. A few times I didn't have the for the higher octane and put in 87. Instant loss of fuel economy, from 31 to 27 MPG. Running 91-93 I get 31-34 MPG depending on the season.

I kept very accurate records on the Tercel. With 87 octane it averaged 33 MPG (with an AT). With 89 it would get to about 36/37. With 91 or higher it would hit 42-44 MPG consistantly. Over the 3 years I owned it I actually saved >$200 using the higher grade gas.

I haven't been keeping such detailed records on the tC, but I know I jump from 27-29 to over 30 using the higher grade gas.

Just my 2 cents...