i usually get 94 octane level for my fd. but recently i meet two rx7 (3rd gen) owners who said fds run well on 89s or 87s just as well, and that lower octane contents are okay for the rotary engine.

any insights???? do i just pay more money for gas???? or am i saving the engine????

 

The lower the octane, the more combustible the gas. So, it is ok to run the lower octane if you are running very low boost (less than stock). The higher octane gives you more margin for error in running higher boost before detonation begins occuring. If you have access to 94, that's what you want to run.

 

If you run 89 or 87, not only will the ECU reduce power, but you will risk detonation. To save 10 cents a gallon, I think not. Be glad you can get 94, us poor souls in Cali are forced to use 91 and pay $1.90 for it (or more).

 

Damn cali and it's gas... I thought I had it bad. I use to only run 94 until the gas prices started going up. I was filling up and on the little price chart the price for the premium was like $1.80 or so... I thought I was paying that price for the 94. Wrong, they dont even list the 94, you only can check the price at the pump. I was paying like 10c more. I'm broke though... if I had the extra $ for gas I would always get the 94.