Question for turbo owners: what octane do you use?

What octane do you put in your CX-5 turbo?

  • 87

    Votes: 17 38.6%
  • 89

    Votes: 2 4.5%
  • 91

    Votes: 8 18.2%
  • 93

    Votes: 17 38.6%

  • Total voters
    44
Just out of curiosity was Phillips 66 tested? No Chevron here and Shell are all in inconvenient places. I tend to consider Phillips 66 and BP to be good as well.

Also how big was the actual difference?

Those were not tested as they are not common brands in the area. But I believe they are both to tier so would be good. It's really about the additive packages. The main objective of my post was to show there are differences between brands rather than to suggest using a specific brand. If we put a different car or type of engine on the dyno would gave the results been different... I couldn't say because we didn't try other vehicles.
 
Yea Philips 66 is top tier, has 93, and there is one by the house and the office so its convenient.
 
Those were not tested as they are not common brands in the area. But I believe they are both to tier so would be good. It's really about the additive packages. The main objective of my post was to show there are differences between brands rather than to suggest using a specific brand. If we put a different car or type of engine on the dyno would gave the results been different... I couldn't say because we didn't try other vehicles.

We often drive up to Brookings or Goldbeach for a weekend git away several times a year.

I have done many DYNO runs in fact 2 years ago I did a total of 99 in one year. The local muffler shop did (now it is not legal in CA don't ask) car shows and often asks me to run the DYNO. I owned at one time a convention floor mounted Chassis DYNO ,portable DYNO and engine Dyno, so I am at least sorta experienced with using them. And I am very OCD about setting up the base line programming so the runs are very accurate and I can repeat the perimeters "DELTA" for comparisons of engine changes. I never really paid attention to much to what anyone used for fuel besides most of them were "spiking" the fuel with octane boosters to get better DYNO printouts or that "selfee" next to the DYNO Monitor with their top numbers. But what fuel used was always a conversation and I still seem to hear Union 76, Shell and Chevron as the top fuels used. While I am sure their were CostCo, BP and Sinclair fuel users I doubt with that crowd anyone was going to admit using it. LOL With my automotive industry business associates all over the US and a couple other countries , ASE informational , All DATA updates and information ,TSBs, etc and a few other periodicals most of us have mentioned minor diviability issue cleared up by simply suggesting to our customer to use Chevron or Shell predominantly. While I can't say on this subject none of us ever did proper testing to say with any facts the true outcome to using strictly those fuels I can say at least for one platform most all service dealership as well independent shops that service the BMW/MINI most all recomend to use Chevron fuels.
When I race brackets and use Chevron running a specif gravity test and times having to use Shell or other fuels I did find that Chevron tested a little more predictable. But using other fuels never showed in my average ET's running handicapped racing. so I never gave it to much thought. In the Explorer I will use whatever fuels,the MINI's only Chevron,the PT mostly, Safeway fuels which could be anything,except when I race and then only Chevron with a little bit of xylene. shhhhh! ;) The S/G Camaro when I was still professionally NHRA class racing I only used 76 or Socal Race fuel. All the motorcycles either 76 or Chevron except the RG which I ran a custom mix of fuel. So although it may seem like my loyalties was favoring Chevron I do use other fuels.
Oh the MAZDA only Chevron...unless while traveling can not get it. And then I always carry a small bottle of my own cocktail of fuel additive to add to the tank to get by until I can fill back up with Chevron. ;)
You know it funny but no one mention how the spark plugs like different fuels. but I won't start that conversation on this forum. I already looked at a few dozen threads and responses and there is a lot of "tribal wisdom" concerning what spark plugs to use and how long they can last between changes....wow!!! LOL Not one member mentioned doing any proper spark plug testing to even find the best spark plug gap let alone running the engine on an oscilloscope to see what the ignition system was doing with the chosen spark plugs and choice of gap? LOL
 
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We often drive up to Brookings or Goldbeach for a weekend git away several times a year.

I have done many DYNO runs in fact 2 years ago I did a total of 99 in one year. The local muffler shop did (now it is not legal in CA don't ask) car shows and often asks me to run the DYNO. I owned at one time a convention floor mounted Chassis DYNO ,portable DYNO and engine Dyno, so I am at least sorta experienced with using them. And I am very OCD about setting up the base line programming so the runs are very accurate and I can repeat the perimeters "DELTA" for comparisons of engine changes. I never really paid attention to much to what anyone used for fuel besides most of them were "spiking" the fuel with octane boosters to get better DYNO printouts or that "selfee" next to the DYNO Monitor with their top numbers. But what fuel used was always a conversation and I still seem to hear Union 76, Shell and Chevron as the top fuels used. While I am sure their were CostCo, BP and Sinclair fuel users I doubt with that crowd anyone was going to admit using it. LOL With my automotive industry business associates all over the US and a couple other countries , ASE informational , All DATA updates and information ,TSBs, etc and a few other periodicals most of us have mentioned minor diviability issue cleared up by simply suggesting to our customer to use Chevron or Shell predominantly. While I can't say on this subject none of us ever did proper testing to say with any facts the true outcome to using strictly those fuels I can say at least for one platform most all service dealership as well independent shops that service the BMW/MINI most all recomend to use Chevron fuels.
When I race brackets and use Chevron running a specif gravity test and times having to use Shell or other fuels I did find that Chevron tested a little more predictable. But using other fuels never showed in my average ET's running handicapped racing. so I never gave it to much thought. In the Explorer I will use whatever fuels,the MINI's only Chevron,the PT mostly, Safeway fuels which could be anything,except when I race and then only Chevron with a little bit of xylene. shhhhh! ;) The S/G Camaro when I was still professionally NHRA class racing I only used 76 or Socal Race fuel. All the motorcycles either 76 or Chevron except the RG which I ran a custom mix of fuel. So although it may seem like my loyalties was favoring Chevron I do use other fuels.
Oh the MAZDA only Chevron...unless while traveling can not get it. And then I always carry a small bottle of my own cocktail of fuel additive to add to the tank to get by until I can fill back up with Chevron. ;)
You know it funny but no one mention how the spark plugs like different fuels. but I won't start that conversation on this forum. I already looked at a few dozen threads and responses and there is a lot of "tribal wisdom" concerning what spark plugs to use and how long they can last between changes....wow!!! LOL Not one member mentioned doing any proper spark plug testing to even find the best spark plug gap let alone running the engine on an oscilloscope to see what the ignition system was doing with the chosen spark plugs and choice of gap? LOL

You sound like a true racer! Agree about not digging too deep into s*** that many won't understand. It takes more testing than people believe to truly get scientific results that are not skewed by improper testing methods or the need to brag.

My wife's otoscope if perfect for reading spark plugs. She always asked why I have her bring it to my race weekends...LOL

And yes, your nose can smell and your eyrs can tear from spent treated fuel. We have a gentlemans agreement to run pump gas at the races but it's easy to tell if someone is running something they shouldn't be.
 
You sound like a true racer! Agree about not digging too deep into s*** that many won't understand. It takes more testing than people believe to truly get scientific results that are not skewed by improper testing methods or the need to brag.

My wife's otoscope if perfect for reading spark plugs. She always asked why I have her bring it to my race weekends...LOL

And yes, your nose can smell and your eyes can tear from spent treated fuel. We have a gentleman's agreement to run pump gas at the races but it's easy to tell if someone is running something they shouldn't be.

That's kool!

I run none pro Drag Racing at Sacramento Raceway
Road Racing at Sonoma Raceway, Laguna Seca
When I raced professionally NHRA (now retired) all over.

And I am still a......auh ....... street....... (cant say it on this forum by the rules) lol
My Nitrous bottles are always full and ready.
You know the funny thing is at this point my MAZDA is the slowest of all my cars. Everything else is either BLOWN or TURBO CHARGED...I even have a PT Cruiser that will do 0-60mph in about 6 seconds. LOL The MAZDA does not even handle half as good as two of my other cars .They are MINI's But hey my sound system in the MAZDA keeps me enjoying every trip I do in with it long or short. (cool)
 
That's kool!

I run none pro Drag Racing at Sacramento Raceway
Road Racing at Sonoma Raceway, Laguna Seca
When I raced professionally NHRA (now retired) all over.

And I am still a......auh ....... street....... (cant say it on this forum by the rules) lol
My Nitrous bottles are always full and ready.
You know the funny thing is at this point my MAZDA is the slowest of all my cars. Everything else is either BLOWN or TURBO CHARGED...I even have a PT Cruiser that will do 0-60mph in about 6 seconds. LOL The MAZDA does not even handle half as good as two of my other cars .They are MINI's But hey my sound system in the MAZDA keeps me enjoying every trip I do in with it long or short. (cool)

I have a Z06 and everyone one those pages always talk about how they had a run in Mexico last night...yet some live more than 1000 miles away from Mexico... it's all legal in Mexico...LOL
 
You sound like a true racer! Agree about not digging too deep into s*** that many won't understand. It takes more testing than people believe to truly get scientific results that are not skewed by improper testing methods or the need to brag.

That's kool!

I

And I am still a......auh ....... street....... (cant say it on this forum by the rules) lol
My Nitrous bottles are always full and ready.

I have a Z06
Nice!

Here is a picture I took for you this morning ;)


[url=https://postimg.cc/wtFDsN8m][/URL]
 
No scientific analysis here, but after testing both 93 and 87 octane in my new GTR, I feel no difference whatsoever in daily driving. I can cruise at 75-80 on the highway and still easily accelerate to pass someone as needed. It runs as smooth and has the same feeling of pep off the line, regardless of which fuel I used. Looks like 87 going forward for me......
 
No scientific analysis here, but after testing both 93 and 87 octane in my new GTR, I feel no difference whatsoever in daily driving. I can cruise at 75-80 on the highway and still easily accelerate to pass someone as needed. It runs as smooth and has the same feeling of pep off the line, regardless of which fuel I used. Looks like 87 going forward for me......
2.5T's power curves with 93 and 87 AKI gasolines published by Mazda prove exactly the same thing. "To prevent unnecessary spending on premium fuel, both power ratings are published".

Here's the torque curve:

TC.png


source: https://www.thetruthaboutcars.com/2018/12/2019-mazda-cx-5-turbo-first-drive-your-italian-alternative/
 
No scientific analysis here, but after testing both 93 and 87 octane in my new GTR, I feel no difference whatsoever in daily driving. I can cruise at 75-80 on the highway and still easily accelerate to pass someone as needed. It runs as smooth and has the same feeling of pep off the line, regardless of which fuel I used. Looks like 87 going forward for me......

That's a HUGE advantage the 2.5T has over most other makers' turbos.
 
For now my wife is under strict orders to use 92(the highest available in my region). Over time we may switch to 87 or 89. She drives easy and I drive for fun😁
 
Ive using the Costco premium gas here in Ontario Canada. I havent put regular gas in it yet since owning it only at just under 2k km on odometer. Costco sells premium for the same price as reg at other gas stations so it makes sense as I live 1.5km from it. Loving this ride so far!
 
Not sure if because my car is still fairly new with 800 miles but I switched to 92 to try it out and my mpg went down even though my driving habits stayed the same compared to using 87. I'll stick with 87 for now as I didn't notice anything different from 92 except worse gas mileage.
 
I've been driving turbo BMWs since they were introduced more than a decade ago. But I recently switched to a new CX-5 Signature. Ran the first tank of dealer gas, then filled up with 91. I think there's a performance improvement, not just a placebo. So here's my question:

Where I live in Arizona we have only 91. But the engine can run on 93 and see improved performance. Should I seek out an octane booster additive?
 
Obviously the gasoline recommendation for this engine is a bit unusual. Most premium vehicles like Acuras, BMWs, Audis, etc. stipulate 91 as the minimum. Mazda, of course allows for 87 but recommends 93 for optimal performance, which begs a couple questions for those who have first hand experience. Is there a noticeable difference in performance and/or gas mileage between 87 and 93? Does the engine run better on 93? If there is a perceptible difference between 87 and 93, what about 89? Is still worth purchasing the turbo if your intention is to run 87?
I have calculated about a 5-8whp difference in 91 and 93 upon closer testing. I use 91 e free and tt. It's the best we have. I make up for the power loss and then some with the corksport intake. If I lived where 93 was, I'd use 93 TT.
 
For those who have ethanol free in their locations:

1- is any of it big name brand?
2- what do you know about the additives in it?

Ethanol free is obviously better than ethanol blends in every respect, everything else being equal.

But is everything else "equal"?
I use e free top tier. Phillip's 66.
 
I'm not sure whether the industry has completely solved the carbon buildup on intake valves with direct injection, so for me, I use Shell 91 (highest in CO) because that one is Top Tier (lower octanes don't appear to be) and recommended by Audi. Another thing to consider is as engines age, there can be carbon deposits on the underside of the head, or piston rings. Either of these can be a source of pre-iginition, so again Top Tier for me. You might not ever notice, just a bit of timing retardation and lower power versus when it was brand new.

I don't know that comparing HP at low RPM is the whole story. Maybe HP is the same but the engine can advance timing with higher octane to get better MPG/HP? If so the only way to know the difference is a series of fillups and compare mileage and see if the price cost is worth it.

There must be significant gains to be made in higher octane or the auto manufacturers wouldn't be lobbying to get the octane changed accross the board nationwide. I was talking with our plant manager just recently and he said the biggest capital investment he see over the next 10 years is to raise octane, he hears the manufacturers want 95. Interesting times.
I agree on carbon and DI. I use mobil 1 EP and TT gas for this reason.
 
Since one would likely not need the extra performance of the higher octane the majority of the time, what if (just an out loud thought for Mazda) ....

There was a separate fuel tank that held say 3 or 4 gallons that you put 93 octane in and fueled the standard tank with 87 octane. Maybe the engine could switch to feed from this high octane tank if the "sport" mode button was selected.

Best of both worlds? Feel like playing? Push the sport mode. Droning along in traffic on the daily grind then your burning cheaper fuel. What could go wrong lol.

I know it's just a thought in a dream world but hey, I've got extra time on my hands for dreamy thoughts lol.
 
Since one would likely not need the extra performance of the higher octane the majority of the time, what if (just an out loud thought for Mazda) ....

There was a separate fuel tank that held say 3 or 4 gallons that you put 93 octane in and fueled the standard tank with 87 octane. Maybe the engine could switch to feed from this high octane tank if the "sport" mode button was selected.

Best of both worlds? Feel like playing? Push the sport mode. Droning along in traffic on the daily grind then your burning cheaper fuel. What could go wrong lol.

I know it's just a thought in a dream world but hey, I've got extra time on my hands for dreamy thoughts lol.
Bruh...we cant even get a decent regular fuel tank, and you wanting auxiliary special tank?!
 
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