Octane?

flynbob

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Mazda cx5
I know the cx5 2.5 uses 87 but does anyone use mid grade or premium? With those high compression ratios I wonder if there would be any performance improvement with the other fuels?

Thanks!

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There are a few threads on that. Some say that they see a difference with higher octane in certain conditions, some say no. Worth doing a search to see what people say and there are some posters here that have good technical knowledge.

But I warn you - it's like the joke about economists. Question - is there any economist that really understands the economy. Answer - well , there are two. But they disagree.
 
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I always believe in real data. I have yet to see any data from dyno runs that would suggest that going from 87 to 89 or up causes a real difference. Ed
 
I always believe in real data. I have yet to see any data from dyno runs that would suggest that going from 87 to 89 or up causes a real difference. Ed

There has been real dyno data that 91 octane showed a slight difference in power and fuel economy. However it is not enough to offset the 30-40 cent a gallon difference.

In the summer heat, the engine will pull more timing from the performance and in extreme heat you might even have some minor pinging on 87, which goes away with the 91 octane.

In the attached PDF article AAA uses the 2.0L Skyactiv for the results.

http://publicaffairsresources.aaa.biz/wp-content/uploads/2016/08/Premium-Fuel-REPORT-FINAL3.pdf
 
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Thanks for the replys guys. And let me apologize for failing to search ahead of time for other threads on the topic. I am better than that and had a duh moment.

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Easy for me to say because I'm getting reimbursed for the cost of gas, but I've found that my 6 runs much smoother on premium than on regular.
 
I started putting in 91 about 6 month ago and have not stopped.
I notice a difference.
It's worth the $2.50 to me.

Once you do 91 for a few weeks, then go back to 87...you can tell right away.
Less pep...this car needs all the pep it can get. Cause it doesn't have much to begin with.
 
The Mazda CX5 in Australia takes 91.

The federal government has announced that it's going...too much sulpher.

The next one up is 95 and about 10c a liter extra.

These people are clowns.
 
The Mazda CX5 in Australia takes 91.

The federal government has announced that it's going...too much sulpher.

The next one up is 95 and about 10c a liter extra.

These people are clowns.

What you need is an ethanol mandate and then you can get 91 at 10c a liter extra.
 
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In the attached PDF article AAA uses the 2.0L Skyactiv for the results.

http://publicaffairsresources.aaa.biz/wp-content/uploads/2016/08/Premium-Fuel-REPORT-FINAL3.pdf

Wow mazdadude thanks! What a cool report! I only run 93 in 90+F weather when driving up steep hills going to/from work. It helps in the high temps to keep the engine from feeling sluggish, but otherwise I run 87 year round. I love cool summers when I don't have to bother with a "hot weather" pricey tank.
 
I've tried a few tanks of 93. It made no difference in performance or, more objectively, mileage. Not worth paying 75 cents a gallon more for nothing, in my case.

I think people who believe they can tell a difference either have very extenuating circumstances (towing maximum weight in 110*F weather), or are experiencing a placebo effect.
 
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The Mazda CX5 in Australia takes 91.

The federal government has announced that it's going...too much sulpher.

The next one up is 95 and about 10c a liter extra.

These people are clowns.
Like in Europe、Asia, Australia uses RON (Research Octane Number) for octane rating at the gas pump. In US and Canada we use AKI (Anti-Knock Index) or "(R+M)/2". So your 91 octane is equivalent to our 87 octane regular gas. And your 95 octane is equivalent to our 91 octane premium gas.
 
Higher octane burns more slowly then lower octane gas. It's used mainly for turbocharged cars to avoid detonation. The higher the octane, the LESS likely it is to ignite under pressure. You won't see power or MPG gains out of a car that has been designed for 87.

If you're looking for 2 HP at the flywheel, it's better to buy an eBay intake or something. :)
 
I've tried a few tanks of 93. It made no difference in performance or, more objectively, mileage. Not worth paying 75 cents a gallon more for nothing, in my case.

I think people who believe they can tell a difference either have very extenuating circumstances (towing maximum weight in 110*F weather), or are experiencing a placebo effect.
I agree. Mazda programmed US version SkyActiv-G engines only for regular gasoline and they don't take advantage of using higher octane premium for higher output. But this's different story in other regions and they can have a little higher horsepower by using premium gas.

I use regular gas for my VW Passat even though the 91 octane premium gas is "recommended".

But in Arkansas you've to pay 75 more per gallon for the premium gas?! In our area the most I've seen so far is 56 more and mostly is 30 more!
 
Like in Europe、Asia, Australia uses RON (Research Octane Number) for octane rating at the gas pump. In US and Canada we use AKI (Anti-Knock Index) or "(R+M)/2". So your 91 octane is equivalent to our 87 octane regular gas. And your 95 octane is equivalent to our 91 octane premium gas.

Thanks for the detailed explanation...I did work for Texaco/Caltex for a few years and I knew there was a difference.

My complaint is the government has come out without any warning [or time schedule] and has said 91 is going.

I use 91 in my SP23 and that works perfectly. So whatever the time frame I'll have to go [forced] to 95.
 
Thanks for the detailed explanation...I did work for Texaco/Caltex for a few years and I knew there was a difference.

My complaint is the government has come out without any warning [or time schedule] and has said 91 is going.

I use 91 in my SP23 and that works perfectly. So whatever the time frame I'll have to go [forced] to 95.

They haven't said 91 is going. They've just floated it as one of several options. Doubt it will happen, at least anytime in the next few years. Would you want to be the Govt that puts up petrol prices by 20c per litre?? Good way to lose if you ask me.
 
They haven't said 91 is going. They've just floated it as one of several options. Doubt it will happen, at least anytime in the next few years. Would you want to be the Govt that puts up petrol prices by 20c per litre?? Good way to lose if you ask me.

It's just another great big new carbon tax...(unamused)

Yeah floated very sneakily. It barely made the papers.
 
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