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GAS PRICES! Can we go from premium to regular?

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Old 03-04-2011, 10:07 AM
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Thumbs down GAS PRICES! Can we go from premium to regular?

I know everyone is suffering from the rice of gas prices. I want to know if it's REAL critical if we go from premium to regular or even plus gas? Prices for Supreme is $3.43 - $3.47

Right when I started liking V-Power gas prices go up

I know it's a stupid question, but I need some input.
Old 03-04-2011, 10:08 AM
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i wouldnt go lower than 89
Old 03-04-2011, 10:12 AM
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Originally Posted by dgutierr90
I know everyone is suffering from the rice of gas prices. I want to know if it's REAL critical if we go from premium to regular or even plus gas? Prices for Supreme is $3.43 - $3.47

Right when I started liking V-Power gas prices go up

I know it's a stupid question, but I need some input.
My original engine had 110 K before I pulled it. And the only reason I pulled it was to put in a ported and balanced assembly in its place.

All 110 K were on 87 octane.

Originally Posted by The Reverend
i wouldnt go lower than 89
Rationale, or just because?
Old 03-04-2011, 10:15 AM
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the rationale is me being nervous

my engine has low compression at 85K with 91 octane
Old 03-04-2011, 10:26 AM
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Rotaries were designed to be low octane motors. I ran 87 on my 04 till 104K miles. No real difference between 93 and 87 for me. If you are nervous run premix. But the cost will be about the same as running premium, but 87+premix is WAY better than premium fuel only.
Old 03-04-2011, 10:30 AM
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good info, i'm glad i opened my stupid mouth
Old 03-04-2011, 10:31 AM
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agreed with aseras.

premix + 87 is better than just 91+

but there have been some engines that receive knocking or "marbles in a can" type of thing, when using 87 but there were under lying problems to begin with.

If you got your car used then its a gamble, just be more alert to issues poping up. Also the car will be a little sluggish with 87 as the combustion of the octane isnt as high, so you will loose probably 2-3hp.

If your 8 is brand new, start premixing a couple tanks before you throw in 87 and work from there. Then it should equal out to around 91 octane.
Old 03-04-2011, 10:33 AM
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Originally Posted by dgutierr90
I know everyone is suffering from the rice of gas prices. I want to know if it's REAL critical if we go from premium to regular or even plus gas? Prices for Supreme is $3.43 - $3.47
Don't complain then... it's $4 where I live.

89 should be no issue. In fact, there was a time when I ran 87 with no obvious effect, but then later I decided 89 is the minimum I'll use. With that, I ran the car quite a bit. No problem at all.
Old 03-04-2011, 10:38 AM
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Always amazed at how seldom people google before posting...

What's the difference between 91 and 87 gas? --> http://answers.yahoo.com/question/in...8094016AA2ts2x
Old 03-04-2011, 11:33 AM
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do the math. On a 10 gallon fill-up you are talking about only $3 or $4 dollar difference between regular and premium.
Old 03-04-2011, 12:00 PM
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**knock knock**
Old 03-04-2011, 12:38 PM
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Originally Posted by dgutierr90
I know everyone is suffering from the rice of gas prices. I want to know if it's REAL critical if we go from premium to regular or even plus gas? Prices for Supreme is $3.43 - $3.47

Right when I started liking V-Power gas prices go up

I know it's a stupid question, but I need some input.
its only a couple dollars for a full tank between regular and premium. do you think its worth the risk blowing up the seal? ffs, work harder.

Last edited by jasonrxeight; 03-04-2011 at 12:52 PM.
Old 03-04-2011, 01:30 PM
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Originally Posted by Aseras
Rotaries were designed to be low octane motors.
???
Old 03-05-2011, 10:16 PM
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I've been running the last 6 years with regular in the RX with out any issue. If you don't knock don't throw money down the drain, use regular.
Old 03-05-2011, 10:38 PM
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there is a reason people use high octane fuel, and it's not just because they like spending more money.

can you use lower octane? of course. should you? that depends on what you're doing with your car.

http://www.ftc.gov/bcp/edu/pubs/cons...tos/aut12.shtm
Old 03-05-2011, 11:17 PM
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If you live at a higher altitude you can actually get away with 87 octane more easily.
Old 03-06-2011, 12:51 AM
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Originally Posted by jasonrxeight
its only a couple dollars for a full tank between regular and premium. do you think its worth the risk blowing up the seal? ffs, work harder.
I agree. What's 4 or 5 bucks? I just don't think it's worth saving a few bucks over.
Old 03-06-2011, 12:54 AM
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Please explain to me how premix allows you to run a lower octane? Geesh.

Oh, and seriously, if the $4.00 is killing you then maybe you should have bought a Corolla or Civic.
Old 03-06-2011, 01:02 AM
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yay!! for another gas thread.
Old 03-06-2011, 07:24 AM
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where I live the price differential between Regular and Premium has always stayed the same regardless of price per gallon. So I dont get the rationale for changing to Regular. Its not good for the car, Sounds like a beef on the price of gas
Old 03-06-2011, 08:08 AM
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Originally Posted by adamwzl
[snip]
premix + 87 is better than just 91+
[snip]
If your 8 is brand new, start premixing a couple tanks before you throw in 87 and work from there. Then it should equal out to around 91 octane.
Does premix include an octane booster?

One other interesting detail. The page that Jason posted from his '09 owner's manual is pretty strongly worded against regularly using less than 91 Octane. Series I owner's manuals (at least the one for my '06) did not have that wording. Instad of the paragraph that says "...temporarily for emergency purposes...", my maual says

"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."

so it looks like SII are more demanding than SI. Either that or Mazda is now colluding with the makers of high octane fuel.

I still use premium.

Ken
Old 03-06-2011, 09:46 AM
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If you can't afford premium then you should probably have bought a Prius instead. :P
Old 03-06-2011, 09:55 AM
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Originally Posted by Aseras
Rotaries were designed to be low octane motors. I ran 87 on my 04 till 104K miles. No real difference between 93 and 87 for me. If you are nervous run premix. But the cost will be about the same as running premium, but 87+premix is WAY better than premium fuel only.
this is the biggest f-king horse **** of the day.

Any previous Rotary got 10:1 compression?

Premix can boost Octane rating ? Last I know Premix will LOWER your AKI.

What about gas quality? some have 7% ethanol and some have 18% ?

do you live way on top of the mountain or you live right by the sea level ?

you really need to get your facts straight. stop giving out bs crap.



As for "gas prices", its 4 bux a gallon now for premium and 3.7 for Regular (87). I still drive my 8. The price sucks? hell yea. I just drive my Mazda 3 more often, thats all.

Last edited by nycgps; 03-06-2011 at 09:57 AM.
Old 03-07-2011, 04:06 AM
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Several months ago I got curious after reading a topic like this one, and decided to try running regular 87 octane for a couple of tanks to see how it would affect running quality, performance, fuel consumption, etc.

I won't do it again...

In normal driving, there appeared to be no noticeable effects good or bad. However, under hard acceleration, it would start pinging somewhere in the mid-range. Apparently, the knock sensors have a limited ability to adjust the timing for preignition, either that or I have a lot of carbon build up (but I don't think so). This was at night with the weather in the 50s - hate to imagine how bad it might be in hot weather.
Old 03-07-2011, 05:42 PM
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Mazda recommends using higher than 91 octane so you should use that. It says in the manual you should only use lower than 91 octane if there is no 91+ available.


So if you think you know more than Mazda who spent millions designing the car.......... then by all means go for it and save $1.30 a tank of gas.


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