Owners manual says use octane 87 or higher

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This is for a 2017 Honda HRV and it has a surprisingly "high" compression ratio of 10.6:1 with only port injection. Is this a case where it'll run on 87, but it'll run better with a higher octane?

I don't mind running 89 since I already do in my two other vehicles. I'm more worried about getting the best fuel economy out of it.
 
87 is just fine for that engine, which isn't turbo or DI
smile.gif


If you're in a high-altitude area or ever visit one, you still have to use 87. The wording in the manual is mainly to tell people up in the mountains that they can't use the 85 offered up there and that they still have to use 87 regardless of altitude
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You have to do the math to see if any increase in fuel economy is offset by the increased cost of higher octane fuel.
 
Originally Posted By: slacktide_bitog
87 is just fine for that engine, which isn't turbo or DI
smile.gif


If you're in a high-altitude area or ever visit one, you still have to use 87. The wording in the manual is mainly to tell people up in the mountains that they can't use the 85 offered up there and that they still have to use 87 regardless of altitude
smile.gif




Don't want to derail this thread, but according to Exxon Mobil (from 2013) that is still up for debate ... and there have been no changes since:

"ASTM is also addressing this issue and a ballot to remove the discussion regarding altitude adjustments was issued last fall and addressed at the December meeting. There were a number of negatives submitted for a variety of reasons, but predominantly because there was almost no pertinent data presented that the octane requirement adjustment for altitude was invalid. It was decided to withdraw the ballot and, instead, move forward with some scientifically designed experiments to elucidate the subject."
 
My Cruze is a port-injected gas, turbo I-4 with 9.5:1 compression - it's technically an 87 engine but the results every time I've put regular in it tell me it likes 89 or better a WHOLE lot more. Run at least a full tank, or several, of 89 or premium in it, then pump a bunch of regular in it and see if you notice a difference in idle quality and acceleration.
 
Use regular 87 octane. My 1ZZFE has a 10.0/1 ratio. Dont see much diff running higher. The cost of higher octane wont give you the equivalent in better mpg. Ie. Paying 20% more for 93 octane wont give u 20% better mileage.
 
Originally Posted By: A_A_G

I don't mind running 89 since I already do in my two other vehicles. I'm more worried about getting the best fuel economy out of it.


Unless you have your own farm tank what difference does it make? Press the 87 button when you get to the station.

Dodge used to advertise "peak" HP which was unlocked by higher-than-regular fuel. They rated their cars with the EPA on regular, though. How they had their cake and ate it too.

Realistically this is an experiment you may have to do yourself. Consider it in the summer at least, the worst time for knock retard.
 
Our 2.3 EB Explorer requires a minimum of of 87 octane fuel. The OM says that best overall and vehicle performance is achieved using 91 octane fuel. This is especially in high temperatures and conditions such as towing. I'm guessing in other conditions such as mountainous driving, especially in hot temps this applies. Considering premium fuel costs between $0.50 to $1.00 per gallon more than 87 octane fuel and my engine performance and mpg have been more than satisfactory with 87 octane for regular everyday driving overall that's what I'll use. For our June trip to Key West from NJ I'll do what I did last year and make a 90 octane mix using 1/2 87 octane and 1/2 93 octane.

Whimsey
 
Originally Posted By: eljefino
Unless you have your own farm tank what difference does it make?


They are older vehicles with high/very high miles (10 years - 147k & 16 years - 231k). Both ping on 87 so I switched them to 89 and it stopped.
 
Last edited:
Originally Posted By: slacktide_bitog

If you're in a high-altitude area or ever visit one, you still have to use 87.... they can't use the 85 offered up there and that they still have to use 87 regardless of altitude
smile.gif



This is incorrect.

High altitude = less atmospheric pressure = less cylinder filling = less need for octane.

Every gasoline engine design in existence with an option for "high altitude" is a RAISED compression ratio, because power goes down as you go higher.
 
I believe that a higher compression engine will perform better with a higher octane gas. Even if it doesn't get better gas mpg. I also like to make my own blend of 90 octane by mixing 87 & 93. For the same price or less than 89 octane, I get higher octane. And if using gas with more detergent in premium, I get cleaner injectors.
 
My 13:1 SkyActiv is happy on 87. I put 60k miles on an Accord 2.4l using 87 exclusively.

Save your money.

My VFR likes premium but is only 11.8:1
 
Originally Posted By: Whimsey
Our 2.3 EB Explorer requires a minimum of of 87 octane fuel. The OM says that best overall and vehicle performance is achieved using 91 octane fuel. This is especially in high temperatures and conditions such as towing. I'm guessing in other conditions such as mountainous driving, especially in hot temps this applies. Considering premium fuel costs between $0.50 to $1.00 per gallon more than 87 octane fuel and my engine performance and mpg have been more than satisfactory with 87 octane for regular everyday driving overall that's what I'll use. For our June trip to Key West from NJ I'll do what I did last year and make a 90 octane mix using 1/2 87 octane and 1/2 93 octane.

Whimsey



Why all the trouble mixing 1/2 of 87 and 93 to get 90? Just press the 89 button and save all that unnecessary work.
 
Originally Posted By: Linctex
Originally Posted By: slacktide_bitog

If you're in a high-altitude area or ever visit one, you still have to use 87.... they can't use the 85 offered up there and that they still have to use 87 regardless of altitude
smile.gif



This is incorrect.

High altitude = less atmospheric pressure = less cylinder filling = less need for octane.

Every gasoline engine design in existence with an option for "high altitude" is a RAISED compression ratio, because power goes down as you go higher.


Problem is: now I have a full tank of less than 87 gas that’s able to make it from my high altitude purchase site to a lower elevation, maybe even sea level. Many cars can go far enough on a tank of fuel to make that low octane purchase a warranty buster.
 
Originally Posted By: double vanos
Originally Posted By: Linctex
Originally Posted By: slacktide_bitog

If you're in a high-altitude area or ever visit one, you still have to use 87.... they can't use the 85 offered up there and that they still have to use 87 regardless of altitude
smile.gif



This is incorrect.

High altitude = less atmospheric pressure = less cylinder filling = less need for octane.

Every gasoline engine design in existence with an option for "high altitude" is a RAISED compression ratio, because power goes down as you go higher.


Problem is: now I have a full tank of less than 87 gas that’s able to make it from my high altitude purchase site to a lower elevation, maybe even sea level. Many cars can go far enough on a tank of fuel to make that low octane purchase a warranty buster.


"A warranty buster"? Never happen GI! If it worries you that much just take it EASY on the throttle until you can pump a few gallons of premium into that 86 octane swill.
 
Originally Posted By: GMBoy
Why all the trouble mixing 1/2 of 87 and 93 to get 90? Just press the 89 button and save all that unnecessary work.


Because the cost per octane number is ridiculous, that's why.

It's cheaper to blend.
 
Originally Posted By: double vanos

Problem is: now I have a full tank of less than 87 gas that’s able to make it from my high altitude purchase site to a lower elevation, maybe even sea level. Many cars can go far enough on a tank of fuel to make that low octane purchase a warranty buster.


HUH?

What vehicle?
Most modern ECU controlled engines adjust timing & mixture to compensate just fine.
 
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