went to the pump the other day to fill up and accidently put in 87 octane.
I always put in either plus(89) or premium(93), so I was slightly concerned as I treat this car better than I treat myself. For some unknown reason, I'm getting WAY better mileage on this tank than I ever have before.
I normally run about 220 miles before fill up, but I'm at 275 right now and the light hasnt come on. I'm not getting the rotary pops from the exhaust like I was on the plus and premium either. I'm confused. Is it the summer blend fuel? Whats making my 8 run better than it has before? Am I doing something bad by not using a higher octane fuel?

I could read hours upon hours of the mpg threads and possibly find my answer or I could ask a quick question and hopefully one of you people will have the wisdom to help me out. And a preemptive "bite me" to Mugatu, who will most likely drop by at any second to tell me to "search". ;-)

 

Many others have seen an increase in gas mileage w/lower octane fuel so that part is normal. Most likely, you are negatively affecting performance to some degree as well.

You might also see an increase as you put more miles on the car.

 

Haha

 

Thats pretty good! good find mate. Hows the preformance by the way? or havent you been strapping it? for 275+ miles, there is a chance you have not stepped on the gas with this tank. I often switch between regular and high octane but when i have high octane in it, I'm on the gas too much to give it a chance to give me good economy

 

this tank has had slightly more highway miles, but I've still been taking trips to the redline when the backroads are clear. Dont get me wrong, I like the MPG increase but I'm not obsessed with it. I havent felt any noticable loss in power from the lower grade fuel.
Was mainly wondering If I'm hurting my car and why Im not hearing the rotary pop heartbeat.

 

use the lowest octance gas your car can run reliably. a higher octane gas is guaranteed to work. a lower octance gas isn't. a quality 87 octane will work fine.

 

If a lower octane runs fine in your car you are often better off. As long as the knock sensor is not to aggressively retarding your ignition low octane runs better in a rotary engine because of the long slime combustion chamber. I have heard of rotary race engines running as low as 80 octane.

 

Exactly. Octane levels are there to prevent pre-ignition (dieseling, aka knock). For best economy use the lowest octane that won't cause pre-ignition, in the RX-8's case 87.
Note however that optimal performance may be somewhat affected by lower octane.

I generally run 92, but occasionally 87 or 89. No knock at the lesser. But I do like the 'stomp on it' confidence of the 92.

 

you guys are soo st000pid....H|gh3r 0ct@ne Gives gas MORE EXPLOSIVE POWER!! Yoo fools are losing MAD HP!!!!!111ONE!!

 

Lol! Higher octane does not give you more horsepower. That is gas corporation propaganda to get people to buy higher octane when they don't need it. Higher octane is for higher compression engines. If you use too low of an octane you risk pre-ignition as previously stated. A rotary however has less risk of damage. Higher octanes don't give you more horsepower and they don't run cleaner or any bullshit like that either! If you can run 87 and not damage the engine, then there isn't a point in putting in a higher octane and I recommend it. Just remember that the engineers specifically designed the engine to run on 91 - 95 octane. I'm sure if the car could run on 87 without ANY damage they would have recommended 87, since that would have increased RX-8 sales.

 

thread closed