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Regular vs. Premium fuel

65K views 98 replies 42 participants last post by  Type34 
#1 · (Edited by Moderator)
I know there are endless online discussions about this topic. From what I'm reading, 87 is perfectly fine, given all the sensors and computer-aided timing, but to get maximum performance and efficiency 91 is recommended. Does anybody disagree?

What I also don't understand is the Honda Pilot has identical compression ratios, and only requires 87. Are there other elements of the engine that are benefiting from 91? Thanks!
 
#2 ·
There should be a sticker on the inside of the fuel door. It states on my 18 RLX and 19 MDX "87 Minimal and 91 recommended". I couldn't find anywhere in my 19 MDX or 18 RLX owner's manual saying 87 octane minimal (only 91 octane). I would go with the fuel octane rating you want as long as you don't go below 87 Octane. I get my fuel from Sam's or Costco at home and when I travel and stick with 91 Octane (91 Octane at Sam's/Costco is almost same price as 87 Octane at a corner gas station).
 
#3 ·
I know there are endless online discussions about this topic. From what I'm reading, 87 perfectly fine, given all the sensors and and computer aided timing, but to get maximum performance and efficiency 91 is recommended? Anybody disagree?

What I also don't understand is the Honda Pilot has identical compression ratios, and only requires 87. Are there other elements of the engine that are benefiting from 91? Thanks!
Pilot = 280 HP, MDX = 295 HP, they are tuned differently, I would go with what the manufacturer recommends which is 91 (premium), but it is your vehicle so you can do what you want.
 
#4 · (Edited)
You only get the 290 hp at 6200 rpms at sea level. Probably a much smaller hp and mpg difference between the Pilot and MDX (if any) in normal city or hwy driving. Just on paper, the Pilot and MDX engine seem 99.9% identical. I would think it would be a bonus feature to have the +22 MDX normally run on regular and have a power boost with +91 Octane.

Even my RLX sport hybrid with the 310hp/273tq 3.5L+hybrid powertrain can take regular.
 
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#5 ·
I used to only run 91 on my MDX, then switched to 87 last September. No noticeable difference in fuel economy or performance so I have no reason to switch back.
 
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#6 ·
So you are saying if a person runs regular they get 280 but they run premium they get 295 hp? Based on your logic, the Pilot only achieves 280 hp at 6200. I am quoting HP numbers directly from Honda and Acura. I do not believe you gain a 15 hp advantage by burning premium, it is because the motors are tuned differently which is why it is recommended to run 91 octane or higher. Will the MDX run okay on regular? Yes but you are depriving yourself of maximum performance. This question has been beaten around since the launch of the MDX and if you can afford an MDX you should not have a problem buying premium as the manufacturer recommends. But some people want to cheap out, those folks should have bought a Honda.
 
#7 ·
The +2014 MDX and +22 MDX DI and port injection engines are designed to run on +87 Octane unleaded fuel with up to 15% ethanol. My 06 TSX, 08 RDX, and 11 MDX was +91 Octane required and I always stuck with 91 Octane for every Acura. I think it is great Acura has designed such a flexible engine to fit the needs of the owner.
 
#8 ·
From where I read earlier.... go with what it "REQUIRED" (due to how engine is tuned). Looks like both 3rd and 4th Gen MDXs are required 87+, but recommended 91+. It should be fine to run on 87 (regular) grade. I have always fill with 93 from Costco since I have 3 Costco gas stations within 15 minutes radius (in three direction) and it is either on-par or cheaper compare to regular grade off local gas station (i.e. Exxon, Sunoco, shell, etc).
 
#9 ·
As I said, you can use regular but you get decreased performance, why does everyone try to make this seem so difficult? Use premium for best performance use regular for decreased performance.

From the owners manual:
■ Fuel recommendation
Unleaded premium gasoline, pump octane number 91 or higher
Use of a lower octane gasoline can cause occasional metallic knocking noise in the engine and will result in decreased engine performance.
Use of a gasoline with a pump octane less than 87 can lead to engine damage.
 
#12 ·
Honestly, you are driving an SUV to do daily task. Not sure if premium fuel is needed unless you are driving spirited like a sports car or towing. V6 is a great flexible engine, unlike turbo. I also used premium gas on 1gen Acura RDX since it is turbo and designed to rev up!
 
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#13 ·
Below is from 2022 MDX manual...

116771


I know there are endless online discussions about this topic. From what I'm reading, 87 perfectly fine, given all the sensors and and computer aided timing, but to get maximum performance and efficiency 91 is recommended? Anybody disagree?

What I also don't understand is the Honda Pilot has identical compression ratios, and only requires 87. Are there other elements of the engine that are benefiting from 91? Thanks!
 
#14 ·
Thanks for the info in manual. Confirms what was said before of being A-OK with using 87 octane or higher for the +22 MDX. The MDX will adjust the timing to reduce or eliminate the knocking. Some parts of NM and west TX only have 86 or 90 octane at the pump is the reason why I only use 90/91 octane (whatever happened to mid-grade).
 
#17 ·
Both the 3rd Gen and 4th Gen 3.5L engine is rated at 290hp. Only the RLX 3.5L is rated higher at 310hp for both the hybrid and non-hybrid versions.

I live and drive mostly at 5000-6800 feet. I'm already down on hp for the NA engines by 15%-20%; which, make the engine work harder compared to lower altitude vehicles to maintain the same performance. Factor in posted speed limits of 75-80 mph (set my ACC 5-7 mph above that). I like the feature with the Acura (you can't get with the Honda) of getting a touch more performance with 91 Octane. Plus, you will see regular 85-86 octane gas sold at higher altitudes because of thin air and richer air-fuel ratio (87-88 for mid-grade) Using 87-88 octane in Denver or ABQ is probably like using mid-grade 89 octane near sea level.

I lived in Seattle/Tacoma and Phoenix in my younger days with commute times of 10-20 hrs weekly of sitting in my car inching forward slowly. I can understand one of the reasons for using the 87 octane option for the MDX. My commute is now 2 miles in New Mexico and I usually ride my bike to work.
 
#19 ·
116784
 
#23 ·
I know there are endless online discussions about this topic. From what I'm reading, 87 perfectly fine, given all the sensors and and computer aided timing, but to get maximum performance and efficiency 91 is recommended? Anybody disagree?

What I also don't understand is the Honda Pilot has identical compression ratios, and only requires 87. Are there other elements of the engine that are benefiting from 91? Thanks!
I own a 2014 MDX. In Colorado, 85 octane is offered. I have used 85 since day 1, 80K miles ago. I experience excellent performance still to this day. I tried 91 for a couple of weeks and noticed no difference.
 
#24 ·
I know there are endless online discussions about this topic. From what I'm reading, 87 perfectly fine, given all the sensors and and computer aided timing, but to get maximum performance and efficiency 91 is recommended? Anybody disagree?

What I also don't understand is the Honda Pilot has identical compression ratios, and only requires 87. Are there other elements of the engine that are benefiting from 91? Thanks!
Technically, 87 works only because the
I know there are endless online discussions about this topic. From what I'm reading, 87 perfectly fine, given all the sensors and and computer aided timing, but to get maximum performance and efficiency 91 is recommended? Anybody disagree?

What I also don't understand is the Honda Pilot has identical compression ratios, and only requires 87. Are there other elements of the engine that are benefiting from 91? Thanks!
Technically, if everything is operating correctly, the computer can manage compression, combustion and whatever to accommodate 87 octane. You will necessarily produce less power than using 91 or greater, so fuel economy is better with premium but you pay a premium for that gas. If your car’s computer or its managing components are not operating perfectly, the lower octane can cause knocking/ping and potentially engine damage in the long run. That’s why I’ve always used 93 octane - I won’t quibble over a couple hundred bucks each year to produce more power and to eliminate the risk of engine harm by lower octane gas. Not worth it.
 
#25 ·
In SoCal premium fuel is about $0.20 more than regular. If you drive 12,000 miles a year and your MDX gets about 15 miles per gallon, then you're paying about $160 a year more for fuel. That equates to about $13.33 a month...or less than 3 Venti coffees at Starbucks. Put the recommended fuel in and call it a day.
 
#26 ·
If you drive 12,000 miles a year and your MDX gets about 15 miles per gallon, then you're paying about $160 a year more for fuel. That equates to about $13.33 a month...or less than 3 Venti coffees at Starbucks.
And since the 3rd gen MDX gets better mileage than 15mpg the extra cost for premium amounts to even less.

And since I don't drink coffee and have never purchased anything at a Starbucks I have plenty of money to just use the recommended premium fuel.
 
#36 ·
I think the reg -vs- premium debate would be less of an debate if you take into account the total picture of our expenses. I think we sometimes look at every purchase as a single action not related to other expenses in our lives.

1000 miles per month
20 mpg combined avg
50 gal of gas used

To keep the math easy:
$100 a month spent on gas @ $2.00 per gallon for regular gas
$125 a month spent on gas @ $2.50 per gallon for premium gas

$25 extra per month on gas OR $6.25 per week extra.

$6.25 per week can be off-set, you can use premium with zero impact to bottom line, and you might even have more $$$ by:
  • one less fast food/take out visit per week
  • changing cell phone plans or keeping your old phone longer (still have my iphone 6S+)
  • cooking more at home
  • stopping internet streaming service you don't use that much or gym membership you don't attend regularly
  • paying down a credit card and being charge less monthly interest
  • paying off another installment bill early
  • adding LED light bulbs in your home for future savings
  • doing more DYI around the house or vehicle
 
#39 ·
I think the reg -vs- premium debate would be less of an debate if you take into account the total picture of our expenses. I think we sometimes look at every purchase as a single action not related to other expenses in our lives.

1000 miles per month
20 mpg combined avg
50 gal of gas used

To keep the math easy:
$100 a month spent on gas @ $2.00 per gallon for regular gas
$125 a month spent on gas @ $2.50 per gallon for premium gas

$25 extra per month on gas OR $6.25 per week extra.
Your analysis assumes you will still get only 20 mpg on premium. But elsewhere I read that people are getting 10% better mpg on premium.
 
#37 ·
This shouldn't be a debate because there is not a "right" or a "wrong" fuel to use so long as the fuel is 87 octane or above.

Thank you Acura for giving your customers the CHOICE to use whichever fuel they prefer without causing damage to their vehicle.

For many buyers premium fuel may cost too much more than regular to justify the marginal improvement in fuel economy and performance.
For many buyers the cost difference between premium and regular is negligible, so there is no reason to not use the higher octane blend.

Everybody wins.
 
#38 ·
Personally I will be using 87 octane. Actually this was a deciding factor for me. My wife was looking at the Lexus GX whatever SUV which she absolutely loved. Aside from the outdated technology and the small cargo volume (which was very deceptive as the SUV appears quite large), a big turn-off for me is that the naturally aspirated V8 in that Lexus required premium fuel. Gas mileage rating was something like 16 - 22. Give me a break. I already have two gas guzzlers that require premium. I didn't want a third especially with gas prices on the rise again.
 
#41 ·
Light duty driving where small to moderate throttles are used you can get buy with regular. The vehicle can more than compensate for the lower octane.

If you drive it like you stole it, I suggest Premium. Gas prices are high but my new 2022 Advanced was not cheap either.

This is just my opinion, you are welcome to have yours.
 
#42 ·
If you keep your vehicles 3-5 years or lease and always rotate out of them, I wouldn’t spend any time worrying about putting lower octane / lesser quality gas in the vehicle. The problems associated w doing so will reveal themselves later and it will ultimately be someone else’s issue. I’ve had my ‘02 X for going on 20 years as the original owner. Suffice it to say, premium always and I’ve never had engine issues at 220k.

I won’t buy a car coming off a lease because people do things like running the cheapest gas they can find in them.
 
#44 · (Edited)
These engines have the same compression ratio as the pilot, same horsepower and torque. Running regular is fine, they only say prem recommended really to fit into the luxury brand basically. The manual says prem if you are towing or driving hard but even then I think regular is fine given the same engine as pilot. Now maybe if they upped the compression and made more power than pilot, them prem would be required at that point.

If your engine knocks, the ecu will retard the timing so it doesn't happen again. One or two knocks isn't going to do any damage.
 
#47 ·
My 2011 MDX pinged and knocked like crazy when filled with anything other than supreme. Now that I need to replace my car this is a major consideration for me as premium and supreme are way more expensive than unleaded fuel in my area. Have their engines evolved since then to better handle lower octane fuels? I don't care for the extra performance, but do care about paying for premium fuel.
 
#48 ·
The 2007-2013 MDX required premium fuel because it was not designed to run on anything less.
The new engine that the 2014-current MDX use is the same one used in the Honda Odyssey, Pilot, Ridgeline, and Passport. It features direct injection and variable valve timing. It was designed to run on 87 octane so no knocking will occur when filling with regular.
87 required, 91 recommended for maximum performance.
 
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