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Discussion Starter #1
I have stuck primarily with 93 octane fuel, various brands, but have tried 89 octane a few times. Following is the Octane vs. Trip Computer MPG vs. Calculated MPG for several tanksfull (similar combined city/highway driving):

Octane--Comp. MPG--Calc. MPG
---93-----------------------16.00
---89-----------------------14.05
---93---------15.8--------15.37
---93---------16.1--------16.20
---93---------16.1--------15.55
---93---------16.7--------16.18
---89---------16.3--------15.81
---89---------15.1--------14.58
---89---------15.4--------15.01
---93---------15.7--------15.36
---92---------15.7--------15.33
---93---------15.7--------15.70
---93---------16.0--------15.23

There's not really enough difference to shake a stick at, and I noticed NO performance differences, nor did I notice any pinging with the 89. I am currently using 93, but I'm not sure why when I look at the figures.
 

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The BTU efficiency of high octane fuel is actually slightly less than regular.
In otherwords, as you go down in octane, you are using fuel with slightly better combustion efficiency, but the computer is retarding the spark, which will result in less engine efficiency. Regardless of what the pump says, there is a certain amount of tolerance from that number depending how old the fuel is, some small variability in refining, if the fuel truck has some residue of lower octance fuel, etc. etc.
We don't have 93 in my area, so I just run what is labeled 91, and take it as it comes.
 

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We have 87, 89, and 93 in my area. I think the stratagy I'll use with my new MDX is to fill up with 93 when the tank is close to empty, then fill up with 89 when the tank is 1/2 empty, run till almost empty, then repeat the process. If towing I'll only use 93.
 

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"I think the stratagy I'll use with my new MDX is to fill up with 93 when the tank is close to empty, then fill up with 89 when the tank is 1/2 empty, run till almost empty, then repeat the process. If towing I'll only use 93."

What is the purpose??

Assuming you fill up once a week you will save a whopping $75 per year!
 

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frostyra said:
I have stuck primarily with 93 octane fuel, various brands, but have tried 89 octane a few times. Following is the Octane vs. Trip Computer MPG vs. Calculated MPG for several tanksfull (similar combined city/highway driving):

Octane--Comp. MPG--Calc. MPG
---93-----------------------16.00
---89-----------------------14.05
---93---------15.8--------15.37
---93---------16.1--------16.20
---93---------16.1--------15.55
---93---------16.7--------16.18
---89---------16.3--------15.81
---89---------15.1--------14.58
---89---------15.4--------15.01
---93---------15.7--------15.36
---92---------15.7--------15.33
---93---------15.7--------15.70
---93---------16.0--------15.23

There's not really enough difference to shake a stick at, and I noticed NO performance differences, nor did I notice any pinging with the 89. I am currently using 93, but I'm not sure why when I look at the figures.
Is your combined mileage always this bad? What percentage is city versus highway? My combined readings 50% city and 50% highway are between 18.9 and 20.1 MPG.
 

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I use 93 octane from various stations, and I get approximately 16 to 18 mpg. Virtually all of my driving is city (although, here in south Florida some of the city driving is at speeds of over 50 mph, regardless of postings!). My trip computer usually tells me that I average about 30 mph. Granted, with only 1100 miles on the odometer, this is not the most conclusive data!

Finally, unless someone can convince me that running 'cheaper' gas through this vehicle absolutely will do no harm, I will continue to use 93 octane regardless of results.
 

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Maik said:
[B
What is the purpose??

Assuming you fill up once a week you will save a whopping $75 per year! [/B]
That will get me closer to the 91 octane requirement per the owners manual.

Hey $aving $75 here and there is the reason I could afford the MDX.
 

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rvehock wrote:

"Is your combined mileage always this bad? What percentage is city versus highway? My combined readings 50% city and 50% highway are between 18.9 and 20.1 MPG."
Maik

I have seen a bunch or posting reporting very poor (<16mpg city/highway mix) mileage results. Do you have some secrets for the rest of us? I am still very disappointed with our overall mileage. On absolutely flat, open road, we can get >20mpg, but usually we get around 15 or 16 (often getting under 14mpg).

Mike
 

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me95124
Something is wrong with your X or you are leaving out some details.
As for the use of 87-89 fuel, the knock sensor will only retard the timing with the onset of knocking. This only happens when you jump on the throttle or are pulling a grade.
Try 87 sometime and you will be suprised.
Like the Pilot, the X runs very well on regular.
 

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if you want better mileage, next oil change switch to 5w20 as the 02 owners manual suggests. I went from 15-17mpg in the city to 17.5-19. Hard to find oil. I ordered Amsoil full synthetic online
 

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Discussion Starter #11
rvehock: my goin'-to-work driving is approx. 80% city & 20% highway, with ~11 traffic lights or stop signs. On straight highway driving, I'll get up into the 24-25 mpg range.

AcuraMDX2002: every time I fill up (unless I'm trying to keep an eye on overall long-trip mpg) I reset the trip computer. For the first 30 miles or so, it jumps all over the place, but then slowly settles down. The highest trip average I have ever noted is almost 26 mpg.

Yes, I do love the X's accelerating capabilities, and take advantage of them often! :2:
 

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creese said:
if you want better mileage, next oil change switch to 5w20 as the 02 owners manual suggests. I went from 15-17mpg in the city to 17.5-19. Hard to find oil. I ordered Amsoil full synthetic online
I keep reading that the 02 manual says 5w20, but I only saw 5w30. hmmm.

As a newby with only less than a month on the X, i find the gas mileage acceptable but nothing to write home about. I think my ML actually did a little better. Then again, the X engine may need more run in time to get to optimum gas efficiency and i have just under 2000 miles on it. Any one have any recollections on how the economy improved with engine break in? Be interesting to hear. Thanks. (i'm getting in the 15-16 range with mixed driving):21:
 

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edepa said:
I keep reading that the 02 manual says 5w20, but I only saw 5w30. hmmm.

As a newby with only less than a month on the X, i find the gas mileage acceptable but nothing to write home about. I think my ML actually did a little better. Then again, the X engine may need more run in time to get to optimum gas efficiency and i have just under 2000 miles on it. Any one have any recollections on how the economy improved with engine break in? Be interesting to hear. Thanks. (i'm getting in the 15-16 range with mixed driving):21:
A change in the oil viscosity recommendation was incorporated with an updated owner's manual in mid-2002.
 

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DaleB said:


A change in the oil viscosity recommendation was incorporated with an updated owner's manual in mid-2002.
dale, what was the updated version? the 5w30 i assume? mine had a build date in late May.
 

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Discussion Starter #16
This isn't another Enron -- is it?

A-HA! The plot (and oil) thickens! I wonder if the 5W-20 was a misprint in the '02 manual ('01 was 5W-30) and Acura finally caught it, or if they had problems and figured they ought to go back to good ol' 5W-30? Either way, Acura ought to let all owners know that the recommendation is now 5W-30 -- shouldn't they?

I wonder what the service manual says. If it said 5W-20, has it, too, been changed?
 

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I agree with AcruaMDX2002, as long as a cheaper gas does no harm to the engine.

Will using a cheaper gas cause the engine to sound sluggish?

Remember the old pinging sounds of 4 cylinders.
 

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frostyra
Just checked my new Factory Service Manual. It specifies 5W-20
I just did my 1st oil change @ 3800 mls and my average mpgs is noticably better and thats with Mobil 1 5w-30.
Its 90 today and I feel better that I've got a 30 lubing my baby.:cool:
 
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