Gas requirement

[Chibana]

MazdaUSA answered my Tweet:

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Mazda USA
@MazdaUSA

@MatthewHarrell4 Hey, Matthew, although it will advance engine timing, the 2014 Mazda3s are tuned specifically for 87 octane.
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So there you go: Like most recent model year cars, it will advance timing if you use higher octane gas. Even if it's only 5 hp, it's worth it to me, and it should result in a tiny bit better fuel efficiency, too.

 

[LH451]

So its fine to us 91 then?

Sounds like I'll give it a couple tanks of 91 and see if its any good. Its only 1-2 bucks more per fill up. It's usually around 5% increase in hp, not much but if it yields more mpg's I'll take it.

 

[npaladin2000]

All engines adjust timing. That's all about knock/ping avoidance. Engines adjust timing based on how fast they're spinning too. Put it on a dyno and see if the power changes.

 

[LH451]

I'll wait until someone puts it on a dyno before trying I don't have the time to do so and I don't know where the closest one is to me plus its probably gonna cost a pretty penny lol

 

[Chibana]

All engines adjust timing. That's all about knock/ping avoidance. Engines adjust timing based on how fast they're spinning too. Put it on a dyno and see if the power changes.

The question to Mazda was specifically whether it will *advance* engine timing to make more power on higher octane gas. They replied pretty clearly to the affirmative (as is the case with most modern cars). They didn't say anything about where they cap the timing advance, but it sure sounds likely that it will make more power going from 87 to 93 octane gas. People will spend hundreds of dollars on a cat-back exhaust or intake to gain 4 or 5 whp (which I will also likely be doing). Even if the increase in flywheel hp is only 5 on 93 octane, that's worth it to me.

Cost really isn't that bad. I'm always baffled when people freak out about the price difference. At 20 cents a gallon difference, with my 85-mile one-way commute 3 times a week, it works out to something like $20/month. I spend more than that on lunch for me sometimes.

 

[npaladin2000]

No, all he said was

@MatthewHarrell4 Hey, Matthew, although it will advance engine timing, the 2014 Mazda3s are tuned specifically for 87 octane.

You can bet it means exactly what it says, no more and no less, and was written by a PR guy to make sure it didn't commit them to anything from a legal perspective. Fact is, he can say that because, like I said, all engines advance their timing to some degree as RPMs go up.

Like I said, dyno it. That's the only thing that's going to tell you for a fact if your power goes up when you use higher octane gas.

 

[Chibana]

The Road & Track article was enough for me to put 93 octane in the car. Mazda could have also simply stated, "No, higher octane won't make more power." That would have been the safest answer if that was their primary concern and it was the truth. Unless there's a rather large HP gain going from 87 octane to 93 octane, a dyno may not be definitive proof, either, given that it would have to occur on different days. I'm certainly not spending a couple hundred dollars for that gamble. With the Road & Track article, Mazda's reply, slightly better fuel efficiency on higher octane, and the fact that most brands of gasoline reserve their best quality and/or quantity of additives for their premium gas, premium gas seems like a good bet to me. Most people likely wouldn't spend more than $10 extra month going to premium.

 

[Chibana]

I received an even more useless answer via email. Not surprising, I suppose. I wasn't expecting a reply at all. Basically, the guy told me that the car is designed for a minimum of 87 octane, and I can certainly use higher octane, but he has no information he can give me regarding how much more power it might make on 93 octane. That's not really what I asked, but whether the car was programmed to advance timing on higher octane gas like most newer cars, or if it was capped at 87 octane. Ford seemed to have no problem stating in their source book that the new Focus will make more power on higher octane gas. Granted, that book wasn't necessarily intended to be read by owners, but it was intended to be read by salesman, who would then (theoretically) have the knowledge to pass on to consumers.

For now I'll be sticking with 93 octane. I've been trying to be good about fuel efficiency and stay off the Sport button lately, so I don't have any real sense of any power improvements. Even if there is one, I suspect it would be hard to notice on a car with 184hp from the factory, especially if the car isn't pulling timing on 87 octane as the Focus apparently did.