I moved to 89 on the recommendation of my dealership's service manager, without any noticeable difference, including no appreciable difference in mileage. See my mileage log in the signature.

 

I filled up the other day with 93 for $1.81 a gallon.

 

If Vegas had 93 Octane I would Use 93 Octane.. but they only provide us with 91 so that is what I use. I would never use anything less than that.

 

$1.81 a gallon - WOW! I miss Texas and Oklahoma.
93 is $2.39 in Los Angeles.

 

If you are using av gas, that gas as 10 times the lead that leaded auto gas used to have. that is ablut the worst stuff you can put in a rotary and will foul out the cat. It's burn rate is also considerably lower than auto gas and at high rpm will be less efficient. It was designed for aircraft that have a redline fo 1500rpm to 2700 rpm.

John

 

I use 87 octane fuel all the time, from Union 76.
A few weeks ago I was kind of stranded and forced to buy Costco gas.

Towards the end of tank I was on the freeway and I heard pinging at speeds over 84 mph.
At 80 mph no ping.

Pulled over, filled up with Chevron 93.. no pinging at any speed - for security I tested beyond 84 mph :D

I drive a lot without radio off so I hope I would've heard the pinging if it had occured earlier. My lesson learnt is that brand gas is better than Costco/noname.

I am back to using 87 gas from Union 76 now. No pings.

 

The $1.60 that I would save at each fill up for going with the lower grade isn't justifiable for me. TX does have a few perks. Just a few though.

 

I've tried multiple tanks (in a row to average out the mixing) of 87, 89 and 93. I notice that the 93 has better performance at higher RPMs. In my normal around the town driving (shifting below 5K), I don't notice a difference between any of the fuel grades.

I drive 89 normally...93 if the price diff isn't much.

 

I live in western NY and I use 93, its about $2.25 a gallon but like you say, its a $30k sports car and I expect to pay when filling it up.

 

93 In LA. There is a place in Norwalk you can by "racing fuel" something like 98. Real expensive and I haven't been by the place in about 12 years.
It maybe you can only get 91 in the bay area.

 

Just finished 1st tank with the Shell 93. I usually get 18.0 - 18.3 mpg with all city driving - sunroof always open/ AC on nearly 80% of the time. This tank (with the Shell 93) - same conditions - 19.8 mpg.

 

.... let me get a bottle of your fineist bottle of Mobile 93....

Yea dats rite...only 93 in my baby....

 

I have been running 91 octane since I got my 8. Due to our elevation (I am at about 5500' where I am sitting now), that is the highest we get around here. I don't see the point in trying to save money on gas since spending the money on the car.

 

Well, this thread pushed my buttons BIG TIME.

First of all, Rotary engines are known not to need higher end fuels. That is a long proven fact. Check out the Rotary info in airplanes etc. The regular gas is quite sufficient.

Secondly, I owned a car for 5 years that required premium or else. No other grade would work and the manufacturer stated such (Mazda Supercharged Millennia S ) with a warning.

When I bought the RX8 I was buying premium and the thing was sooting up and choking along running rough at idle, etc. THen I saw the light and switched to regular. The car came to life. For me it was not just the saving of money but performance - it improved. Several posts to the problems with hi-test and the additives and slow burn have been addressed here from persons much smarter than myself on engine matters. Buy what you want but realize that the life of the engine is not going to shorten with regular gas. If anything the reverse may be true with the soot and buildup of additives not needed in rotaries that are in high test to burn slower.

oh, and as far as a particular brand goes, specifically SHELL, a month or so ago, in our area several of their stations were given contaminated gas and several problems occured for people - could happen to ANY brand but still... Some years ago I read an entire report on gasoline and about BMW certification/rating. If i remember correctly the only Nationally available brand that was certified was Amoco. The engine eating phosphates were low and additive mix did not show heavy build-up.

IT all comes down to what you can tell the engine runs well with. I noted engine sounds with both premium and regular and other things and I am constantly aware - don't play the radio that much. The engine runs well on both. I HAVE NOTED that weather effects perfomance though.

 

I use 93 also...boyfriend kept saying...u can try regular....it happened..but only by accident..i wasn't paying attention and i put regular...first tank..was fine....kept getting the "told u so"...so i filled up once again...


guess it didn't like the 2nd tank..cuz i kept hearing a knocking sooo bad!! hahah I'd rather use 93 then have to hear that...

 

I am a huge fan of V Power as well, I do zero interstate driving when I started to use V power I have been averaging 18 mpg in the city and I drive it like I stole it.

 

i use mostly 93. when i don't its 91 or 89. i've never tried 87.

 

yeah...87 does me no good i hate the knocking

 

I've run only 87 since the day I got my 8. I haven't even bothered to try anything higher. I haven't heard any "pinging" or weird sounds coming from the engine even when rev'd up to 8 or 9k.

I'm not sure what pinging sounds like in a rotary, anyway. Is it the same type of "knocking" sound as in a piston engine?

 

Rotary engines do not knock (no pistons). As I have posted before, when I ran 93 and the temp got to freezing the car would not idle at startup. It constantly died unless you sat there and gave it gas (thankfully it never flooded). The dealership service manager said the same problem happens to their VW's if they run 93 in them. I thought he was full of it until I called/e-mailed Mazda twice to verify. They said there is no reason to run high grade with a rotary engine unless you just want to shell out more bucks.
I use 87 and get 19-20.25 mpg 50/50 city/hwy driving.

 

Well heck now your all confusing me, the manual says to run high octane, the dealer told me to run High Octane. Many here say that they have confirmed that its not true. To end my confusion Im just gonna go with the mid-grade.

 

I filled up with the Shell V-Power yesterday. The last tank I had was full of BP 93 Octane with DCS/TCS off and I got 18.9 mpg which is my highest. I am going to see how many mpg I get from the V-Power if any different. I am thinking about getting the Shell card and save the 5% or however much it is.

Keep in mind that maybe the car will run fine on lower octane but you are going to lose performance because of the burn rate.

Dean

 

I switched to 87 octane Shell last October; been running it ever since. My car not only runs fine with it, but actually runs better. Idle is smoother and slow starts are smoother. I picked up about 1.5 mpg after switching compared to 91 octane. I average about 19.5 mpg with a mix of 50/50 freeway/street driving. I do not baby the car; I enjoy the performance. No pinging or knocking.

I experimented with every gas brand available in my area, and I discovered that gas brand was far more important than octane rating. We can't get 93 octane here in southern California so 91 is all that's available. First brand choice is Shell; second is Chevron. There are enough of those two around that I don't even bother with any other brand. Costco and Sam's Club gas was junk; even at 91 octane. My Mazda Tribute however doesn't mind Costco or Sam's gas.

Prices here in southern Cali are usually much higher than elsewhere; we get gouged royally all the time here. We're typically 50 cents a gallon or more higher than other parts of the country. Right now Shell down the street is $2.19 for 87 regular. Today is August 7, 2004. I see some of you posting prices of $1.80....we haven't seen those kind of prices here in a LONG time.

Shell 87 runs just fine for me; good performance, good mileage. I have almost 19,000 miles on the car and I've been using 87 for 10 months.

 

i know what i heard...it didn't sound so great...as soon as i heard that..i asked him if he heard the same thing (since he was the one in the first place who told me it wouldnt do anything)...well...it was very loud and obvious...i would barely hit the gas at first until he ran into the store and bought octane booster or something...the noise then went away..and i use 93 w/o any noises...