Mazda CX-5 The CX-5 CUV debuts Mazda's SKYACTIV® TECHNOLOGY and is unique for its impressive fuel economy, responsive handling and bold style

Fuel grade

Old Aug 7, 2019 | 07:55 AM
  #11  
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Originally Posted by Litehiker
Au contraire, mon frère. With a high compression naturally aspirated engine or a forced induction engine (supercharged or turbocharged) which is, by definition, high compression, higher octane gas will give more power. That oil company employee must have been speaking of "normal compression" engines where, true. it would be wasted money.

When I owned the last generation twin turbo RX-7 I found a great increase in power using costly 100n octane fuel. And how I loved the unique aroma of that potion!
They should make a man's cologne out of it.

Eric B.
My comments are for ALL engines, normally aspirated and forced induction alike. That said, forced induction engines do have a higher critical altitude, but in the end, the rules are just the same.

Relative to your RX-7; entirely different engine architecture, as for power increases from 100 AKI fuel (note there is no such a thing as 100 octane automotive fuel here in North America); I highly doubt there were any gains unless you were able to fit an aftermarket computer to the engine.
 
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Old Aug 7, 2019 | 07:56 AM
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Originally Posted by kant57
I cannot find any info on this in the forum so I'm posting a new question. I know Mazda recommends using Regular fuel in the CX-5 but I'm getting crappy mileage in town, roughly 19.5 mpg.
I thought I'd try Premium but made no difference but now it runs like a race car.
So I've got 2 questions:
1 Am I doing any harm to the engine running Premium?
2 If I add something like a K&N air filter will that improve things like mileage?
Thanks, Mike
Runs like a race car? I'm sorry to tell you this but it's all in your head. Spend the extra if you like, it won't do any harm, except to your wallet. A normally asperated, non high compression motor, will not make a noticeable increase in power when burning premium than it will burning lower octane fuel.
 

Last edited by Conrad 16.5; Aug 7, 2019 at 08:04 AM.
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Old Aug 7, 2019 | 08:05 AM
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Mazda designed the NA 2.5L to run on regular octane. The spread between regular and premium is about 70 cents a gallon where I live, which does add up. Buying premium on the NA 2.5 is literally lighting money on fire.
 
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Old Aug 7, 2019 | 07:19 PM
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Originally Posted by Chocolate
Mazda designed the NA 2.5L to run on regular octane. The spread between regular and premium is about 70 cents a gallon where I live, which does add up. Buying premium on the NA 2.5 is literally lighting money on fire.
Agreed. Where I live the delta between regular and premium is high as well. So I go with regular.
 
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Old Aug 7, 2019 | 08:05 PM
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Hi.. First post

I like saving money.. but since I switched from 87 to 89 (mid grade) for my 2019 CX-5 GT, I immediately noticed (why I tried it in the first place) faster starts and less hesitancy. The difference is subtle, but appreciated and worth the 10 cents extra per gallon.
 
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Old Aug 7, 2019 | 08:24 PM
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Originally Posted by tomw.public
Hi.. First post

I like saving money.. but since I switched from 87 to 89 (mid grade) for my 2019 CX-5 GT, I immediately noticed (why I tried it in the first place) faster starts and less hesitancy. The difference is subtle, but appreciated and worth the 10 cents extra per gallon.
I would argue it is all in your head; the fact is, the lower the grade of fuel, the more powerful by volume and the volatile said fuel is, as such, the engine should start and have less hesitance with Regular.
 
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Old Aug 8, 2019 | 07:01 PM
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So evidently the case is quite different when dealing with a turbo charged engine since Mazda claims 227 hp on regular and a whopping 250 hp with premium...
 
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Old Aug 8, 2019 | 08:16 PM
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Originally Posted by Pitter
So evidently the case is quite different when dealing with a turbo charged engine since Mazda claims 227 hp on regular and a whopping 250 hp with premium...
I don't believe anybody has said otherwise. What we have said is to use fuel of a higher AKI than specified by Mazda will not provide you with any performance benefit.
 
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Old Aug 8, 2019 | 09:04 PM
  #19  
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To summarize:

Premium gas increases HP in the CX-5 turbo version.

On the other hand, HP is the same with either regular or premium gas in the CX-5 non-turbo version.
 
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Old Aug 9, 2019 | 07:51 AM
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Originally Posted by tomw.public
Hi.. First post

I like saving money.. but since I switched from 87 to 89 (mid grade) for my 2019 CX-5 GT, I immediately noticed (why I tried it in the first place) faster starts and less hesitancy. The difference is subtle, but appreciated and worth the 10 cents extra per gallon.
As said above, it's all in your head man. The higher the octane the slower the burn rate. How could your car start faster when using fuel that's slower to ignite?
 
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