dean2900

I am amazed by the number of posts of people running 87 octane to save money. I am sure the car will adjust but there is no way to get the same performance on lower octane fuel.

I always pay for the 93 and I expect to on a sports car. I guess I don't understand why people buy a 30k sports car and then put cheap gas in it.

I don't think Mazda put "Use Preimum Gas" just for the hell of it.

Dean

Elara

I only use 93- I used 89 once, but only because I was flat broke that day.

Jogumby

Ya I run 93. When prices were rocketing up a few months back I started running 89-91. RX didnt seem to mind it to bad. I read were Mazda recomends premium & lower octanes may reduce engine life....are they trying to sell premium or trying to help there product last longer......I'd choose the later :p

ArvinC

...the only one. I am a HUGE fan of V-Power (their new 93 octane formulation) by Shell...in fact, there are a number of users here who swear by it because, not only have we have been getting great performance, we've been getting extra miles out of the tank as well! :D

Check this link out
in the Tech Section...lots of information about its formulation and the results some of us are getting by using it.

FWIW, I pay about $2.01-$2.03 for V-Power here in Baltimore.

Arvin

dean2900

You have convinced to fill up next time with the Shell and see if I notice any difference mileage wise.

Dean

PA BATMOBILE

Sunoco 94

Joe M

I was beginning to believe I was the only one also; the only thing that still interests me about octance choice is that, from what I can read here, lower octane gas can give you better milage. If that's true, I'm not hurting anything and I'm not losing performance by using mid-grade (89), I'd use the mid-grade. I've asked the question but can't seem to get a definitive answer about better milage with lower octane. If premium is really "better" for my car, all around, than mid-grade or regular, I don't mind paying the extra .70 - $1.00 for a tank.

RevTo9K

I haven't bought anything less than 92 octane since the early 90s, unless I'm driving a rental car.

DreRX8

I use 93 only--because unlike most users--my car didn't respond well to lower octane--I had a horrific noise that was octane related--so I only use 93.

ilstr8r

I'm not sure if many of you are aware of this, but lower octane fuels will lead to unstable detonation. Some of you have claimed decreased performance and sometimes a strange noise and I can tell you this is because you are losing compression and the "pinging" noise, well that''s pre-detonation.

Since the 13b has such a high CR, you want to make sure that you use an octane capable of handling the correct CR. You are risking the life of each component to your rotary each time you force your 8 to swallow sub-par gasoline. Which frustrates me as I don't have one yet. Look up some long discussions on the subject anywhere, probably at howstuffworks.com. Oh yeah, long-time lurker, first time poster!

JJ01769

I only use 93 as well. I tried 89 for one tank and couldnt really tell a difference but I figued since 93 was only 8 cents more a gallon, might as well.

srm858

I have used both 87 and 93 and I can't tell the difference in engine performance or mileage. I sometimes feel like I should use 93, but Mazda says in the manual it is OK to use lower octane. Why not save 20 cents per gallon?

Phlash

The difference between 87 and 93 octane here is 20 cents a gallon......what a screw job!

shelleys_man_06

With Texas' cheap fuel prices, I only use 93 octane.

mysql101

I used 87 and not only saved money at the pump, but got around 50 miles more per tank.

I did that for two tanks, then went back to the premium fuel - but the only reason for that was because I didn't want to risk future problems, not that I saw any evidence of complications.

I don't drive all that much and so the fuel cost doesn't matter all that much to me. In different circumstances, I might consider continuing with 87.

MTCD01

I've only used 93, I switch between Shell, Mobil, and Exxon.

marcj1

I've tried near full tanks of 93, 89 and 87. The difference I've noticed is pinging at high revs with lower octane fuel. My current practice is to fill up when the tank is between 1/3 and 1/2 full and I alternate between 93 and 87. I've not noticed any pinging or delta in my mileage. I would bet that, while by no means scientific, the blend comes above (or close enough to) the 91 that Mazda recommends.

irish8

V-Power all the way!! In fact I called MazdaUSA when I bought the car th=o see if I could get a personal recommendation from someone. 91-95 is recommended. 93 is recommended for the US. And the individual did say Shell V-Power!! Good news is I'm in Texas so gas is not supe expensive!!! Sorry for the guys on the West coast and up north.

HeelnToe

Yea, same here, although I swear I heard a rattle/pinging when climbing hills at part-throttle with the 89.

I also got better milage when I first switched to 89, but the milage has consistently improved when using either grade. I'm reasonably happy with 18.55 mpg with my last 93 tankful (country and suburban roads) - and I wasn't exactly babying the throttle

skuzbucket

110 Octane from the local Airport

5 BUcks a gallon, but no pinging or detonation and awesome Throttle Response. Not probably the best thing for the engine, but goes like stink

Nick T

I only use less than 93 when I know my travel is going to be all highway.

rotayking

The only reason mazda wants you to get premium fuel is to reduce the chances of knocking(fuel combustion from compression). That is alll

Kurt Bob

Since Mazda recommends 91 Octane, I switch off between 89 and 93. And for those that are wondering - fuel octane number between the 2 will average to 91 (assuming I have a 50/50 mix of each). The risk of detonation is always greater at high speed/high load conditions; therefore, I would recommend using a higher octane in those situations.

And for what it's worth - lower octane fuel is not "inferior" in any way. It just has a different burn rate.

6speed8

I agree, and pretty much do the same 'mix' between 89 and 93, or if I am lucky to find it, just use 91 octane, cause that is what my owner's manual reccomends.

Dr. Rx

I've always been using 93 octane from Mobile, same gas station on every fill up and I've gotten 20 mpg on every fill. I'll satisfied with my performance so I'll stick with it.