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What would 87 octane do to the car?

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Old Nov 13, 2008 | 12:16 PM
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What would 87 octane do to the car?

So, today I went up to my local Shell station. Put my card in like I always do, and pressed 93. Started fueling and just doing the average gas pump stare into nothingness for a few seconds, when the price $2.12 caught my eye on the pump. I know, for a fact that I pressed the 93 octane switch (in fact, once I realized it was pumping at 2.12, I pulled it out, and tried to refuel again, and found that pressing the button twice on this pump changes it from the 93 octane price to the 87, weather or not the gas changes I don't know ) Regardless, I'm a little worried, even though only about 2-3 gallons got into the car of what could be low grade, they say don't do it. Anyone ever done that before? What could happen? Or will it all be good?
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Old Nov 13, 2008 | 12:23 PM
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you might as well call Mazda and have them order you a new flux capacitor, its only a matter of time befroe it goes out...


seriously search
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Old Nov 13, 2008 | 12:25 PM
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I did search for "87 Octane gas" and got nothing of value, since it returned everything that ever said the word gas in it.

And I'll call them and ask for the Flux capacitor, that way I can go back in time and stop my self from posting.
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Old Nov 13, 2008 | 12:25 PM
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I though the big problem with 87 octane is that it softens the rotors, causing them to mutate into pistons.

It's possible the owner's manual says something about octane requirements.

Ken
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Old Nov 13, 2008 | 01:30 PM
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*sigh*

Go Read teh damn Manual for once.

if for some reason your dog ate ur manual. Go get it on Mazdausa.com

but in short, YOUR CAR WILL WORK WITH 87 damn it. hell I just filled it up with 87 about 2 hours ago.
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Old Nov 13, 2008 | 01:33 PM
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I did the same search and found lots of value related to your question. Here you go:

https://www.rx8club.com/showthread.p...t=premium+fuel
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Old Nov 13, 2008 | 01:36 PM
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I think this RX-8 used 87

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Old Nov 13, 2008 | 01:48 PM
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I filled up with 87 once.

Later that night, I fell down the stairs while my 8 was out with my friends and thats why I have this black eye. I swear my 8 had nothing to do with giving me this black eye.
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Old Nov 13, 2008 | 01:53 PM
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From the owner's manual:

Your Mazda will perform best with fuel listed in the table.

Fuel Octane Rating*(Anti-knock index)
Premium unleaded fuel 91 [ (R+M)/2 method] or above (96 RON or above)

You may use a regular unleaded fuel with an Octane Rating from 87 to 90 (91 to 95 RON) but this will slightly reduce performance.

Fuel with a rating lower than 87 octane (91 RON) could cause the emission control system to lose effectiveness. It could also cause engine knocking and serious engine damage.
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Old Nov 13, 2008 | 01:55 PM
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Some use it some don't.
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Old Nov 13, 2008 | 02:21 PM
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Now that we have all had a laugh at my ignorance, I thank you for the info in this thread.

btw, Mazda said flux capacitors are back ordered... too many people using 87 octane I guess.
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Old Nov 13, 2008 | 02:22 PM
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I switch off, in the city (90% of the time) where I drive a little more aggresive, I use 93 but if I am going on a long road trip in decent weather I use 87 because why waste 93 when you are at cruising speeds most of the trip. In the summer I run 93 always.
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Old Nov 13, 2008 | 07:20 PM
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Originally Posted by expo1
I think this RX-8 used 87

are you sure its not caused by the nawwwwwwz and electric supercharger ?
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Old Nov 13, 2008 | 07:48 PM
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Originally Posted by expo1
I think this RX-8 used 87

you are correct. It used 87 Octane
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Old Nov 13, 2008 | 07:55 PM
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87 is fine. Just might suffer a slight performance loss. Other people claim to get increased mileage on 87 as well, there are a bunch who use it.
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Old Nov 13, 2008 | 08:03 PM
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Go for it and report it back in a few months...You are the man...I vaguely remember the minimum is recommended 91 octane though for RX8...I might be wrong...
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Old Nov 13, 2008 | 08:05 PM
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I've been using 87 for some time. Actually more like 80% of the time I use 87, and the rest is 93. depends on my mood.

Gas price gone back down a lot so I might just stick with 93 again ... who knows
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Old Nov 13, 2008 | 09:54 PM
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i have a shell that sells 91 and 93 so the 91 is only 20 cents more than the regular vs. 30 - 40 cents for 93 so i feed it constant 91
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Old Nov 13, 2008 | 11:55 PM
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I always get better mileage with 87.

If I'm going for long trips I use 87, if it's stop-and-go city driving all week I go for 93 octane Shell V-Power (no ethanol!).
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Old Nov 14, 2008 | 12:00 AM
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^^^lol sweet avatar!
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Old Nov 14, 2008 | 12:04 AM
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actually i heard your 8 turns into a decepticon with 87.


but thats just what i heard.
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Old Nov 14, 2008 | 02:54 AM
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Originally Posted by newguy
i have a shell that sells 91 and 93 so the 91 is only 20 cents more than the regular vs. 30 - 40 cents for 93 so i feed it constant 91
Ah that's lucky. I never find 91. Grades around me are usually 87, 89, 93. I'd have used 91 if it were available. But now I'm boosted so I'll stick with the 93 all the time now.
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Old Nov 14, 2008 | 03:31 AM
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What the PCM will do if the knock sensor send back a signal? And what is the short term fuel trim do? I guess there is still some margin before reach the limit but stated to use minimum 87 is a safe move just in case somehow the 87 at the pump is not reach what suppose to be. Of cause, if just finished 98, straight red line the car after filled up 87 at a pump station will be a risk. If let the pcm have enough time to adjust the fuel trim, I don't see any problem for filling up the 87.

The car burnt probably due to fuel hose burst or some bad modification workmanship/wrong parts installed. The maximum damage can be resulted for using 87 is just upgrade the number of engine being replaced from the car. This forum alone had so many 2nd or 3rd engine club members and rarely heard anything that related to a blown engine will cause fire at at the same time or just right after. If can't find any other evident for causing the burnt except the fuel, maybe it just the only lemon out of 100 thousand on the road.

Last edited by csl; Nov 14, 2008 at 03:35 AM.
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Old Nov 14, 2008 | 06:44 AM
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Vaguely remember??? I posted the germane owner's manual excerpt above. Geesch!

Originally Posted by sfredrx8
Go for it and report it back in a few months...You are the man...I vaguely remember the minimum is recommended 91 octane though for RX8...I might be wrong...
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Old Nov 14, 2008 | 12:02 PM
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your 8 will be fine man. the first 2 times i filled up my car i used 87 octane and it was fine, just don't do it againn
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