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What about using octane booster with regular gas to compensate?
Pointless, imo. Just use the right grade of gas.
 

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Purchasing a new 2017 mdx in 2 days. What about 89 octane from day one? 20 cents more is a heck of a lot better than 50 to 70 cents.
Thoughts
 

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Purchasing a new 2017 mdx in 2 days. What about 89 octane from day one? 20 cents more is a heck of a lot better than 50 to 70 cents.
Thoughts
The 3rd gen MDX appears to be tuned differently than the others...less power than 2nd gen...I would use what is recommended...I am sure the MPG ratings and stated horsepower are based on recommended fuel.
 

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Purchasing a new 2017 mdx in 2 days. What about 89 octane from day one? 20 cents more is a heck of a lot better than 50 to 70 cents.
Thoughts
:ghetto:

Acura recommends 91.

:lurk::lurk::lurk::lurk::lurk::lurk:

I don't understand the obsession some people have with cutting corners.

:9:

Next we'll see a thread where someone needs new brake pads and asks if they can substitute cheddar cheese, since Costco sells 2LB blocks for a good price.

Or what about using canola oil instead of Mobil 1? Canola is pretty slippery...

:2party:
 

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It appears the current Pilot and MDX have identical engines and transmissions. The MDX is rated at 290 hp and the Pilot at 280 hp. Both get the same rated mpg.

It appears in either vehicle, the primary benefit is the extra 10 hp- a 3.4% difference most people won't notice. I'd be willing to bet the Pilot makes 290 hp on premium, and the MDX makes 280 hp on regular.

However, under certain, very particular conditions, premium can get you a big mpg boost. This is because when it's working in 3-cyl mode, those cylinders are working pretty hard. Under certain conditions, premium may let it stay in 3-cyl mode when it might require all 6 cylinders using regular. That's my hypothesis on why some have noticed a big improvement in highway mpg using premium.

I live at high altitude, where the air pressure is lower, so 91 octane is a complete waste unless you're in a turbocharged car (god I wish this thing had a turbo). 89 or even 87 octane should give me all the performance this engine is capable of up here. However, because of the high altitude, regular here is only 85 octane. That make for quite a spread in cost for regular vs premium here- about 27%! I'm not paying 27% more for 3% more power! I suppose buying mid-grade is the ideal solution, but I can get premium at Costco for the same price as midgrade anywhere else. I think I'll run a few tanks of premium and a few tanks of regular to see if there's any mpg improvement at my conditions, but I think I'll make 100% of my potential power here by throwing in a third of a tank of premium every few tanks.

It's not about "cutting corners"- it's about cost benefit. Paying 27% more for 3% more power....if I'm lucky at my altitude...is not a good cost benefit tradeoff. It'd be like paying extra to water your plants with distilled water- a pointless waste of money.
 

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These threads crack me up. Penny pinchers everywhere....I do like the cheese brake pad idea though...LMAO....

ME, I just burn the recommended fuel and don’t think twice...
 

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These threads crack me up. Penny pinchers everywhere....I do like the cheese brake pad idea though...LMAO....

ME, I just burn the recommended fuel and don’t think twice...
Penny pinchers? Why did you buy an MDX instead of an X5? Probably because it offered a better value to you. Using premium to avoid knock is a good value, but using it to increase power by 3% probably isn't a good value to many. At my altitude, it probably doesn't get me ANY extra power, so it's the equivalent of taking about $300 a year and just lighting it on fire. Why don't you light $300 on fire and then you can be critical of those who opt not to.
 

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FYI:

Comparing the part numbers for 2017 MDX and 2017 Pilot shows the same part numbers for pistons, heads, and camshafts. Factory specs for MDX are 290HP, 267Tq, 11.5 compression ratio. Recommended fuel is 91 octane. For Pilot 280HP, 262Tq, 11.5 CR. and 87 octane.

I would bet that the only difference is a change of spark curve and possibly fueling map when the MDX knock sensor detects a knock. Probably just defaults to the same specs as the Pilot.

I also suspect that Acura tweaks their engine for premium fuel to get slightly better MPG numbers to make the EPA requirements for CAFE standards.
 

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Penny pinchers? Why did you buy an MDX instead of an X5? Probably because it offered a better value to you. Using premium to avoid knock is a good value, but using it to increase power by 3% probably isn't a good value to many. At my altitude, it probably doesn't get me ANY extra power, so it's the equivalent of taking about $300 a year and just lighting it on fire. Why don't you light $300 on fire and then you can be critical of those who opt not to.

I am on my 2nd MDX because I have owned BMW's...that should tell you all you need to know right there. That said, burn what you like in your tank, I'll keep doing my best to burn what Acura recommends. It may be different on the 3rd gen...the 2nd gen I can tell a huge difference in the grades of fuel. A while back, nothing but regular was available...felt like I was dragging a boat anchor behind my 2011.
 

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I'm coming from a BMW 335i as well. I love the way it drove (and I used premium because it's a turbo), but dependability is the ultimate luxury, so opted for an MDX over an X5
 

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335i’s are nice driving cars....now we are way off track... :)
 

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Right on! I totally agree, I was reading through and waiting for someone to bring up the compression ratio fact. Even if that is not what the OP meant, it certainly reads as if they had the two ideas confused.
Can you help with your thoughts and recommendation. I have a 2011 Fully loaded Acura MDX with 120,000 miles. Last summer it started burning fuel (I’ve always used premium fuel). Then this fall it started burning more oil. I’ve been using synthetic oil. Last week it was 2 litres low. I’d only driven about 2500 miles since the previous oil change. We changed the oil again (synthetic) and drove only 250 miles and he oil was low about 1.5 litres. Last week it started rattling, like metal. Metal.
What do you think is the issue?
Also This summer with the price of fuel so high (in Canada) I stated using only 89 octane fuel.
I read something that the issue could be minor, about emissions and the possibility of changing PCV valve.
Thank you in advance for your help! . It’s greatly appreciated
 

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Can you help with your thoughts and recommendation. I have a 2011 Fully loaded Acura MDX with 120,000 miles. Last summer it started burning fuel (I’ve always used premium fuel). Then this fall it started burning more oil. I’ve been using synthetic oil. Last week it was 2 litres low. I’d only driven about 2500 miles since the previous oil change. We changed the oil again (synthetic) and drove only 250 miles and he oil was low about 1.5 litres. Last week it started rattling, like metal. Metal.
What do you think is the issue?
Also This summer with the price of fuel so high (in Canada) I stated using only 89 octane fuel.
I read something that the issue could be minor, about emissions and the possibility of changing PCV valve.
Thank you in advance for your help! . It’s greatly appreciated
the 2011 model is well-known to burn oil. You need to check your oil level regularly and keep topping it up.

The 2nd gen REQUIRES premium 91+, iirc. I wouldn't skimp on it.
 

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You seem to make a large number of mistakes in this post, my guess is you have googled various things and just assume you know what you are talking about.

First, when running regular gas your timing if anything would advance not retard. retarding the timing would make it fire closer to TDC.
Second, yes RPM absolutely can change if pre detonation occurs, compression ratio stays the same, but the time the piston takes to travel has a large and direct effect on timing.
in other words an engine that pre detonates at high RPM might not as much or at all at low rpm.

Third, NO. high compression engines do not require premium. They MIGHT. mazda's would be a good example of this with up to 13:1 on regular gas just fine.

Lastly I have driving my 07 MDX in a variety of conditions while monitoring the timing and not only does the computer seem to sort it out quite well, but comparing regular to premium i see very little difference in Advance.

I'm by no means saying regular is necessary fine for the MDX (although my experience seems to show so), but at least get what you are saying correct.

I have heard engines before that require premium as a few of you put it, and the 2nd gen mdx is definitely not in that category, they run like crap. the mdx on the other hand, mine has 125,000 miles on it and during my 500 miles trip yesterday I averaged 25mpg and saw up to 30 on straights.

I'll let each person decide what they want to run themselves, for myself; if I'm seeing the same timing advance and the same gas mileage I'll keep running regular.
 
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