Octane Rating
- Thread starter youzi
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I actually filled it up 2 days ago with 91 Octane fuel and quite honestly there is a noticeable difference in the performance of the car. I drive the sport MT and the car has more zoom-zoom than before. I currently have about 1600 miles on my CX-5. Some people seem obsessed with fuel economy and thats ok, however, since the car is not that powerful to begin with, a small sacrifice in fuel economy for an increase in performance and the pleasure that a little more power brings is definately worth it for me, especially with the mt. If my gas milage goes down a couple mpg with 91 octane so be it. Anecdotally, the car is less sluggish and sounds better. Pehaps I should really study this like the previous posters but I do not have the time. I will confirm right now that there is a noticeable difference between the fuels. Can someone at Mazda let us know if there is a secret they are not sharing with us?
http://blogs.insideline.com/straigh...86-seconds-plus-cameo-by-patrick-dempsey.html
the above insideline blog entry somewhat confirms the results of people putting in 91/94 octane in their cx-5
the above insideline blog entry somewhat confirms the results of people putting in 91/94 octane in their cx-5
I haven't given the octane thing too much thought, but...
Not all fuels are the same for everyone, at least in the US. Different regions use different blends, some using no ethanol, some 10-15%. In my area, 87/89 has no ethanol. 91 has 10% ethanol and is actually $.10-15 cheaper than "regular".
Most vehicles will get better mpg on the non-ethanol blend. Depends on the season for me... sometimes there is a noticeable difference around 10% better mileage on my Mazda5 with the 87/89. But other times it seems the ethanol 91 does about the same, such as this spring when I switched back to 91 for a while and got nearly the same mpg, even though last winter there was definitely more of a difference. I always watch several consecutive tanks if I'm tracking mpg. Driving @200 miles a day makes it pretty easy to see what's going on.
Anyway, my Mazda5 runs fine on both fuels... can't say I notice a performance difference. I would guess there is more difference from one brand to another, than there is from 87-91, but anything's possible. Lower octane fuel has just as much energy potential as "premium"... just depends on what the engine does with it. It's not a subject I'm too studied up on, or concerned about.... but once I get to driving the CX5 on a daily basis I will sure try out different fuels to see what happens.
Not all fuels are the same for everyone, at least in the US. Different regions use different blends, some using no ethanol, some 10-15%. In my area, 87/89 has no ethanol. 91 has 10% ethanol and is actually $.10-15 cheaper than "regular".
Most vehicles will get better mpg on the non-ethanol blend. Depends on the season for me... sometimes there is a noticeable difference around 10% better mileage on my Mazda5 with the 87/89. But other times it seems the ethanol 91 does about the same, such as this spring when I switched back to 91 for a while and got nearly the same mpg, even though last winter there was definitely more of a difference. I always watch several consecutive tanks if I'm tracking mpg. Driving @200 miles a day makes it pretty easy to see what's going on.
Anyway, my Mazda5 runs fine on both fuels... can't say I notice a performance difference. I would guess there is more difference from one brand to another, than there is from 87-91, but anything's possible. Lower octane fuel has just as much energy potential as "premium"... just depends on what the engine does with it. It's not a subject I'm too studied up on, or concerned about.... but once I get to driving the CX5 on a daily basis I will sure try out different fuels to see what happens.
Mainly what the engine is capable of doing with it.... true.
But energy potential being the same is incorrect.
The energy potential is determined in the test engines that dictate the octane a particular fuel can display on the pump.
So by definition, the higher octane fuels have higher energy potentials (and potential to knock if taking MON mainly into account).
The AKI Octane value display on US/Canadian pumps is an average of RON and MON (R+M/2).
To get AKI, test engines are used which have extremely variable compression ratios (for the RON value) and variable ignition timing (for the MON value).
Simplifying the subject somewhat, the higher the Octane the higher the activation energy (or energy extracted from the ignition).
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8.6 seconds to 60 mph is considerably better than the 2 or 3 drivers for the major Auto magazines. The statement that a higher octane will in theory show modest hp or torque increase. I guess the only way to tell is to measure performance changes i.e. no butt dyno.
I filled with 10.8 gallons of shell 93 fuel. So I'd guess my mixture of what was left of 87 plus my 93 will equal out to about 91 octane. Have not noticed any big changes in mpg or feel yet but ill give it time for the ecu to adjust. Computer is at 34.4mpg right now but of my 3 30 mile trips ive done on this tank one was with the ac on. I'll try to keep driving with it off.
I just ran a tank of 89 in my 5 and got the best mileage I've ever had. Off topic, but just had to mention it. 30mpg for the tank 392 miles @13gal. (EPA rated 21/26)
Is anyone else considering that ethanol blends generally yield lower mpg? I know it's not going to be the same for all vehicles, and 10% ethanol doesn't always make a noticeable difference. I'm wondering how it applies to the skyactiv engine. If it can get better mpg on 91 than it does on 87, it will be a first for me. I'm hoping it runs better and gets better mpg on 91... it's the cheapest per gal locally.
Is anyone else considering that ethanol blends generally yield lower mpg? I know it's not going to be the same for all vehicles, and 10% ethanol doesn't always make a noticeable difference. I'm wondering how it applies to the skyactiv engine. If it can get better mpg on 91 than it does on 87, it will be a first for me. I'm hoping it runs better and gets better mpg on 91... it's the cheapest per gal locally.
With the AKI (Anti Knock) values that the US and Canada use, it's highly unlikely to ever get a fuel that rates as high as 104 AKI.
I think the maximum you're likely to get in Canada is AKI 93. Beyond this requires special engines (often racing engines require above this).
I want to believe that the sensors will automatically pickup that the engine is knocking less if I put in a tank of premium, but my practical side does not believe it.
I have access to a dyno, but at $75 per session, that would be a $150 experiment (one session with 87, one with 93) with dubious expected results.
I was planning to do a dyno when I install corksport's intake for the CX5. But I think I'm in money saving mode at the moment.
I have access to a dyno, but at $75 per session, that would be a $150 experiment (one session with 87, one with 93) with dubious expected results.
I was planning to do a dyno when I install corksport's intake for the CX5. But I think I'm in money saving mode at the moment.
pjensen641
Member
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- 2013 CX-5 AWD Touring Zeal Red
I am an ethanol skeptic, but I must say, I see NO difference in MPG between ethanol and regular. I think you are right, some engine architectures may be less sensitive to it. I ran regular 87 with no ethanol for the first 3 tanks or so, then I have run 2-3 tanks of ethanol. All the same weekly routine. I see much more variation based on how much the wind is blowing in any particular day (2-3 mpg)
Well, I decided to try a tank of premium (93 octane in my state) and the decrease in mileage is noticeable.
I see it every time I step on the accelerator because I am used to leaving my dash on instant MPG gauge (versus avg MPG), MPG is as bad as down to the low twenties and high teens under light load.
First quarter tank has yielded approximately 15 miles less than comparable first quarter tank on 87 octane.
I tried to trick myself into thinking it was because I was making more power, and I was not driving conservatively; more power = more fuel right? Ricer Mathematics...
But I no longer think that is the case because cruising in top gear at 75mph with the cruise control on is registering 2mpg less than usual.
When this tank is empty I'll drop it down to 89 octane and see how that works for me.
I see it every time I step on the accelerator because I am used to leaving my dash on instant MPG gauge (versus avg MPG), MPG is as bad as down to the low twenties and high teens under light load.
First quarter tank has yielded approximately 15 miles less than comparable first quarter tank on 87 octane.
I tried to trick myself into thinking it was because I was making more power, and I was not driving conservatively; more power = more fuel right? Ricer Mathematics...
But I no longer think that is the case because cruising in top gear at 75mph with the cruise control on is registering 2mpg less than usual.
When this tank is empty I'll drop it down to 89 octane and see how that works for me.
I tried a tank of premium from Costco when we were in Florida last week. Can't say I noticed any performance boost and it didn't get us better mileage either. I didn't get great mpg in Florida no matter what we put in it, but the premium may have been the worst for mpg.
One unexpected thing I noticed pretty consistently, was that we could often get the same MPG when running at 75-80mph as we did keeping it 70. I'm a little disappointed with the mpg at 65-70 but happy that is doesn't drop off much beyond that. Sometimes, it seemed I actually did better at 75+, especially in hilly areas. For example, we were clocking 32-33mpg running 80mph between Knoxville and Nashville... with no real wind factor... maybe a light s wind. That's basically the same as other times when keeping it @70.
CX5 MT might be a little different, with it's lower final gear... but the AT seems to like to run fast if you don't have flat terrain or a tail wind.
Of course you will get the best mpg by keeping it under 60, but it's good to know that you don't really take much of a hit if you want to run with the flow @ 80 mph
Anyway.... I suspect the best fuel for mileage is going to be 87.... just like my Mazda5
One unexpected thing I noticed pretty consistently, was that we could often get the same MPG when running at 75-80mph as we did keeping it 70. I'm a little disappointed with the mpg at 65-70 but happy that is doesn't drop off much beyond that. Sometimes, it seemed I actually did better at 75+, especially in hilly areas. For example, we were clocking 32-33mpg running 80mph between Knoxville and Nashville... with no real wind factor... maybe a light s wind. That's basically the same as other times when keeping it @70.
CX5 MT might be a little different, with it's lower final gear... but the AT seems to like to run fast if you don't have flat terrain or a tail wind.
Of course you will get the best mpg by keeping it under 60, but it's good to know that you don't really take much of a hit if you want to run with the flow @ 80 mph
Anyway.... I suspect the best fuel for mileage is going to be 87.... just like my Mazda5
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I was being a little tongue in cheek with my post.....104+ octane is only achievable in Canada with an octane booster or as racing fuel. For the life of me I cannot see how anyone can claim with certainty that using fuel with a higher octane rating provides better fuel mileage based upon a tank of fuel.
Agreed, worth a try.
I'll admit I'm not cheaping out on gas completely, because I use nothing but Chevron regular (w/Techron) 100% of time which certainly isn't the cheapest available gasoline.
I'm curious, why? I really don't know much about all the different gas "options." But if it's really better I'd be interested in learning more.
Well, it's a bit like discussions of religion/politics/oil change intervals probably best to avoid...
. My preference is to use only Chevron gas purchased on a Chevron gas card for audit trail.
. I never pay for and/or use additional additives (plenty of detergent and additives in the Techron, a blend that seems to be highly regarded).
. I never pay for fuel system or injector cleanings (again Techron in gas).
. I have not experienced any gas-related problems in last 16 years straight.
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