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Off Topic Forums => General Chat => Automotive => Topic started by: hamwbone on May 17, 2008, 06:37:00 AM

Title: Super Premium Only?
Post by: hamwbone on May 17, 2008, 06:37:00 AM: I have a 2007 mazada cx-7 which has a 2.3 ltr mzr turbo charged engine. The gas cap and manual say to use super premium only. my understanding is that the mught higher compression ratio in the engine is what dictates that preferred octane gas. skip to the 2008 cx-7.... its identical to the 2007 and doesnt say anything about using super premium only. am i risking anything throwing some regular gas in there? ive done it a few times and havnt noticed ANY diffrence in the way the engine reponds. No misfires, hesitation - nothing. What are your thoughts?
Title: Super Premium Only?
Post by: o The Drizzle o on May 17, 2008, 07:47:00 AM: unfortunately... this will happen.

and if you dont user super ultra deluxe octane... the oil companies wont beable to post record profits year after year. so.. make sure to do your part to make sure they get richer.
Title: Super Premium Only?
Post by: lordvader129 on May 17, 2008, 08:26:00 AM: QUOTE(o The Drizzle o @ May 17 2008, 06:23 AM)

and if you dont user super ultra deluxe octane... the oil companies wont beable to post record profits year after year. so.. make sure to do your part to make sure they get richer.

yeah, that extra 20 cents a gallon makes all the difference in the world, without your 20 cents the executive would have to get a fiat and not a ferrari

anyway, using a lower octane rating than you should can result in decresed performance, and you can get knocking and pinging, but if you havent noticed any of that i dont think there should be an issue, i used to have a car that needed 93 octane, i ran it on 87 once and it started knocking, used 89 for a few weeks and then tried 87 again and it ran fine, lol, guess it just needed to be weened
Title: Super Premium Only?
Post by: StrictPuppet on May 17, 2008, 11:35:00 AM: Octane rating is less of a factor with modern cars as it was in the muscle car era.
Part of the powertrain management system is a knock sensor. This sensor "hears" detonation way before a person does. It is a piezo-electric crystal which is tuned to the vibration that is produced by pre-ignition. The use of a lower quality fuel than is specified may cause pinging, but the pcm will detect it by the knock sensor and retard the ignition timing to compensate for it.
If the pcm needs to retard the timing, you may notice a decrease in power, depending on how much of a timing change is required.
Retarded timing = lower cylinder temp = less pre-ignition (detonation, knocking, pinging, w/e you want to call it)
If there is no/little noticeable power difference, use the lower octane, you will not damage your engine.
Title: Super Premium Only?
Post by: rms2001 on May 17, 2008, 07:14:00 PM: You should be fine. Both of my previous two Lexus said they required 93. I ran 87 or 89 (some times they were the same price) in it all the time with no problems. Than again, neither car was turbo charged either, and as heavy as the cars were with a V8, I don't think I would have noticed if there was less power. Ive been told turbo charged gas engines can be picky about the fuel they burn. All my turbo charged vehicles are now diesels, luckily there is only one grade of diesel (for on the road use any way).
Title: Super Premium Only?
Post by: grim_d on May 18, 2008, 11:50:00 AM: lol 95 is our regular here, 98/99 is premium, 102 is track fuel and 110 is drift spec lol.
Title: Super Premium Only?
Post by: twistedsymphony on May 18, 2008, 12:34:00 PM: QUOTE(grim_d @ May 18 2008, 02:26 PM)

lol 95 is our regular here, 98/99 is premium, 102 is track fuel and 110 is drift spec lol.

That's awesome... 91/93 is premium here... though more recently gas stations have been switching to 91 only since it's cheaper

the occasional station will carry 94, but it's pretty rare.

I'm about 10 miles from a race track and they have a gas station for track events that serves up 98 and 107... but only on track days. I had a special map that I dumped in my WRX once to run on 107... that was an awesome week.
Title: Super Premium Only?
Post by: capboy210 on June 28, 2008, 11:26:00 AM: My car calls for premium. But lately I have putting 87 in it... Works fine, of course i live in colorado, If memory serves right lower octane works better in higher altitude.
Title: Super Premium Only?
Post by: RiceCake on September 18, 2008, 07:18:00 PM: And I use 90 octane, ethanol blend, same cost as 87 octane.

Though, I'm in Canada, and that ethanol is free gas line antifreeze.
Title: Super Premium Only?
Post by: twistedsymphony on September 19, 2008, 08:26:00 AM: FWIW my Vehicross doesn't require high Octane gas.. but I use it

it's worth the extra 20c a gallon because I get about 3MPG better mileage when I use it... which makes up that 20 cent and then some.

running a lower grade fuel will WORK, because the computer will compensate for it, but it will hurt the the life span of your car.

Consider eating junk food, after you eat it, nothing bad happens but a few years down the road you're fat slow, and you'll end up dying 20 years too soon because of a heart attack.