Octane?

flynbob

Member
:
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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2016.5 GT AWD
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.
 

Chris_Top_Her

Banned
Moderator
Contributor
:
San Antonio, Texas
:
'15 CX-5 Miata AWD
11111122.jpg
 

erhayes

Contributor
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2021CX5 Reserve
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
 

mazdadude

ZOOOOOOOOOM ZOOOOOOOOOM
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'16.5 Mazda CX-5 Touring
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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flynbob

Member
:
Mazda cx5
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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leeharvey418

Member
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2019 CX-5 Signature; 2014 CX-9 Touring AWD
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.
 

dragonsback79

Member
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Mazda, CX5, Sport
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.
 
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2018 Mazda CX-5 Akera AWD 2.5L
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.
 
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2016.5 GT AWD
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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2014 Mazda 6 GT with MRCC
...
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.
 
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CX5 GT-R
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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yrwei52

2016 Mazda CX-5 GT AWD w/Tech Pkg
Contributor
:
Plano, Texas, USA
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.
 

Natey

Moderator
Contributor
Patron
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. :)