What Octane?>

uncletime

Member
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2007 MS3 GT Black Mica
whats up guys... i was reading the manual( yes i can read ) and it says just to run 87oc is anyone running higher? should we be running hire? if not how come?
 
uncletime said:
whats up guys... i was reading the manual( yes i can read ) and it says just to run 87oc is anyone running higher? should we be running hire? if not how come?
Regular mazda = any octane

mazdaspeed 3 = 92/93 or higher.
 
jcrystal said:
Actually, 91 is what is specified.....

Yeah, but 93 is better. By a couple of degrees of timing and advance and a couple of hp per some guy on mazda 3 forums who claimed to be a Mazda product engineer.
 
i have a speed.... the manual said "nothing less than 87" i just looked at it... so it didnt really specify what to use.... i have a speed btw
 
uncletime said:
i have a speed.... the manual said "nothing less than 87" i just looked at it... so it didnt really specify what to use.... i have a speed btw

If you're talking about the Owner's Manual, it covers all 3's; sedan, hatchback, 2.0, 2.3, Mazdaspeed, etc.
 
If you read the manual it says only use lower than 91 octane in an emergency when nothing better can be obtained. Lower than 91 octane will cause the car to pull timing and decrease performance drastically. Do not put 87 in a turbo car unless you want it to run like s***.
 
Dreads got it. According to Mazda's own literature it's 91 min octane in the MS3. run 87 in the standard 2.3.
 
i have been filling up with 91 but i was just curious if the manual was right lol... and i figured it was for the reg 3's ...
 
uncletime said:
i have been filling up with 91 but i was just curious if the manual was right lol... and i figured it was for the reg 3's ...

My understanding is that the car was tuned to 91 octane so it could run well with any "Premium" gas solD in the U.S. Of course that is only what I read so...
 
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Filler cap on my car (actually the door) says 91 on it.

Don't skimp on the fuel run 91 or higher (only a few cents more) and be happy with your ride.
 
also the little mini-manual that came with the car (blue and white glossy w/ tabs) says 91 for turbo. Yes, 92/93 is better, but 91 is what a lot of us can use, so thats what we can use. They can't make the car unsuitable for regions of the US because of that.
 
pretty much every performance tuned engine by virtue of compression, turbo or supercharger will ask you to run premium high octane fuel. doing so will prevent knock and running anything less may cause the ECU to go into a sort of "limp mode" to prevent engine damage from low octane or bad gas.
 
Just thought I'd add:

I let a family member borrow the car (I don't do that too often, since last time I did my Mazda Protege ES got totaled), and they filled it up at the gas station for me (as a thanks for letting them use it in their time of need). When I asked what gas they used, I got a puzzled look and the dreaded answer "the cheap stuff".

I was super pissed, but I just held it all in, and then went to the car and pointed where it says "premium unleaded only", to which I got a shrug and a reply that they didn't know any better.

Long story short, I ended up driving it on 87 octane for a tankful, and honestly, it doesn't do any harm IMO. What it DOES do, however, is castrate the engine's power. Instead of smokin' power in 1st, and 2nd, its merely "thrustful", and 3rd-4th-5th are no special event. Once the car is underway, though, there is little difference between 87 and 91. It feels significantly less powerful, say 20hp or more, and the gas mileage is worse. So, I guess if its all you can find, you are safe to use it, but don't expect to be happy about it. But also, don't expect to blow something up. Savvy?
 
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