GbosilTLS07

Is everybody running 93 Octane or are you running 87 or 89? Since it says Premium Recommended it's not "Required." Thoughts? Recomendations?? If you run 87 will it harm the engine? Manual says nothing below 87 or it will harm the engine. Typically in all my previous Acuras I have always run Premium Gas.. TL, TSX...

kinmanc

The funny thing is when I went for a test drive, the salesman explicitly pointed this out, and stressed that it is now OK to use regular gas, as if saving 30 cents per gallon is an important factor in the purchasing of a 50K SUV.

Kyrra

Assuming 10k miles per, you would save around $130 per year (assuming no MPG loss, and a 30 cent price difference). Ya, doesn't seem too worth it to risk engine damage for that price.

printf

I also recommend premium gas only. As Kyrra pointed out, the saving isn't that huge. 12,000 miles/year / 21 miles/gallon * 0.3 dollars/gallon = $171. I would spend $171 for better mpg and engine safety.

GbosilTLS07

-Agreed...thanks all for the input. I know it's not much but I've read all these studies by Edmonds here:

http://www.edmunds.com/fuel-economy/...g-premium.html


It's like.. still...why waste the $ ?

dzionny_dzionassi

i dont know why, but when i am reading all these regular VS premium gasoline threads.... it drives me nuts....
I thought higher octane gasoline burns cleaner? Do you know that New Acura mdx engine is DI engine? Have seen it discussed on BMW and Volkswagen boards about carbon builds up on the intake valves and causes problems with misfires and rough idle.
Why to use regular gasoline when manufacturer recommends/requires premium????
i guess that's what happens when you buy 50k+ and you dont have money left.

GbosilTLS07

Recommend and Require are two different things.
50K+ and no money left? WTF does that have to do with the argument. Obviously you are one of those who light their money on fire, have zero savings and live with their MOM and DAD....man that's a real "Clown" comment you made there.

Checkmate 21

If a few bucks more a tankful is that important. you should have bought a Prius. Nothing is harder on an engine than detonation. These engines are very high compression with lots of cylinder pressure. I would not even consider 87 in my mdx.

If you have no respect for mechanical things than go ahead and run the reg (87 in Ca) gas.

Most premium gas has more detergent in it which will help keep the carbon build up off the injector tips. Remember these are direct injected engines and the injector is in the combustion chamber.

Just bite the bullet and run the good stuff and not worry about it.

Gsmooth33

dzionny_dzionassi

I am sorry sir. Yes you are right, i have no savings, live with my mummy and daddy. And i am sorry that i don't understand definition of Recommend and Require. I am just stupid immigrant who will never save money because i fill up my mdx with premium. Please ignore my comment.

ls973800

For the 14 months that I have been a forum member here, I have read numerous posts pro and con about the premium fuel REQUIRERMENT for the 2nd Gen MDX.

I also read posts about owner's complaining about the Honda Pilot being a "sibling" of the MDX, yet running on regular fuel and getting better MPG. Now the 2014 MDX is using the engine that deactivates cylinders, is a D.I. design, and premium fuel is RECOMMENDED.

Acura has said regular is OK, but you may lose some H.P. That's different than the 2nd Gen when Acura said regular was OK for a temporary use if premium was not available.

So according to Acura, regular is fine and will not cause damage like what was possible in the previous engines. Premium will deliver more power, but is not required.

Being a new engine in the 2014 MDX, if I were to buy one I would stay with the premium fuel.

db22

Timing, efficiency, fuel economy and power is determined during the engine design and the MDX is designed for premium. Yes, it will run on regular because the computer will retard the timing to decrease early detonation. Retarded timing in these engines will reduce the optimum efficiency and you will probably use more gas to acheive the same results there by eliminating any gains that you made by buying the incorrect gas for this particular engine.
Higher octane gas burns slower and therefore has more time in the combustion chamber to create more power but it all depends on numerous factors incorporated in to the engine design.
As a general rule: if the engine is designed for regular then premium is a waste. If the engine is designed for premium then do not use regular.

fxcarden

I run my MDX on beer and banana peels.

Checkmate 21

Retarding the timing will also raise the egt (exhaust gas temperature) which also shortens the life of valve and other assorted parts.

Think of running premium as a pre paid insurance policy.

Be good to your car and it will be good to you.

F23A4

....if there's grumbling about whether or not to use premium fuel (presumably in an effort to minimize fuel cost) then purchasing a $45k+ vehicle probably shouldn't have been a consideration. The Honda Pilot Touring is a more suitable candidate.

yungone501

iTrader: (4)

Wow, I was beginning to think nobody would consider this in the thread. THANK YOU.

Beginning with the j35a8 (07-08 TL-S and 05-08 RL), Acura used an advanced detonation monitoring system by using a more accurate and sensitive knock sensor and ECM that could safeguard the engine much better than earlier models. The ECM can safely remove a decent amount of timing and although you could technically get away with it, why would you depend on a "just in case" feature to save such minuscule amounts of cash? If the knock sensor ever failed, say farewell to that beautifully engineered motor.

Lastly, keeping the ECM lodged in a high knock control percentage state will greatly affect power and fuel efficiency... defeating the purpose of running regular pump gas in the first place.

bforrest

I can't speak to Acura but I was at Infiniti dealer colocated with Acura dealership and looking at the JX35. That also recommends premium fuel. I asked the dealer if it's really necessary because the Nissan Pathfinder has basically the same engine and runs on regular unleaded. The dealer told me they recommend premium but it's okay on regular. He said he uses 89 octane himself and be "quiet" but when they put fuel in the vehicles for test driving it's all 87 octane.

db22

That's why he is a car salesman.

Kyrra

it's not about grumbling about the use of premium fuel, it's trying to understand if premium is really required, and what kind of effect would using regular have on this engine. From what I've read so far, I would definitely stick with premium, but it's still a reasonable question to ask since the manual for this car does say you can use octane 87 or higher fuel.

Also, it is not about the cost of the vehicle, it's about being smart with my money. I will pay for something if I feel it is beneficial or required. But if using regular fuel had no adverse effects, I would be happy to use regular fuel to save some money.

KeithL

I see this debate all the time, this is very simple, RECOMMENDED vs. REQUIRED. Additionally the clarification is clearly in the owner manual. On my M37 the manual clearly says the use of anything other than premium will damage the engine and if premium is not available to only use 1/4 tank of regular and basically drive like a wimp until you can get Premium. If the car says recommended and you drive without any hard acceleration, or loaded down with extra weight then there will likely be no difference in premium over regular. I would love to use regular, but in the end modern performance oriented luxury vehicles are designed to benefit (or require) premium. Sure a few hundred bucks a year is still alot to most of us, but then we are spending a large amount of money on the car, factor it in as the cost of ownership of the vehicle.

F23A4

The question is reasonable but IMHO less so given the application. Again, frugality in consideration of purchase of an upscale vehicle makes for strange bedfellows.

Even if 87 octane were permissable in my MDX, the fact that I'll come up short in the power dept. negates EVER injecting sub-91 octane into my tank.

Type34

As the car-guy of my fam/friends, I get asked this question a lot. I always say error on the side of caution and use 91+ if recommended. However, especially if they're leasing, I factor that in their decision.

Assuming 12K/yr, 20mpg, and a $.30 premium, you're looking at $15/month for 91+ fuel. Some people are more comfortable with a $375/mo payment than a $400/mo payment (yes, I know, that's only 3 Starbucks ventis, but still).

So if you're talking higher MDX lease payments, I would say no, that shouldn't be much of a factor, but premium fuel can def become a price consideration when leasing a vehicle.

...and BTW, there is sooo much awesomeness in this post...

Flame3g

I seen this as well when I went to fill up and then opened the manual and it only states 91(premium)....If you ever get confused just open the manual lol.

ls973800

Your not driving a 2014 are you? That's what the discussion is about, the change in the wording of required vs recommended. Yes, 2013 and older all said required. 2014 says recommended.

Flame3g

I am driving a 2014 and if you look at p.g 383 in your manual it say Fuel recommendation
"Unleaded premium gasoline, pump octane number 91 or higher

Use of lower octane gasoline can cause occasional metallic knocking noise in the
engine and will result in decreased engine performance.

Use of gasoline with a pump octane less than 87 can lead to engine damage".

snookssec

snookssec

2011TL

I tested 87 octane in my 1G MDX and found mpg was reduced about 10%. That reduction in fuel efficiency more than offset the cost per gallon savings.

For those with a 2014 it might be worth running that same experiment. I'm sold with staying with premium.

EL_PIC

Might be better to state 93 vs 91 octane since both can be called premium ...
F.W.I.W. ...
The 3.7 L V6 in my '11 Advance is a 91 octane compression engine regardless of what you use or mix.

db22

I fail to see that leasing or buying is a criteria in a technical discussion of the internal combustion engine. Assuming that you consider a leased vehicle as "your" vehicle then the facts are the same. I think of a lease as it not being my vehicle and it's more like a rental so use the cheapest crap that you can find because you are going to give it back to the owner in 2 or 3 years anyway and give the clapped out engine to the next poor guy.

Flame3g

Its not required to state it because some areas you can only get 93 octane and you can run anything higher than 91 just not less than 91.

Type34

I fail to see this as a solely technical discussion; the OP asked "Since it says Premium Recommended it's not 'Required'. Thoughts? Recomendations??"

That same question comes to me from family and friends when they are deciding on purchasing or leasing a vehicle. They ask for my recommendation, just as the OP has asked for our collective opinion.

I notice from your sig that you haven't leased recently, but using the probably 50-60 transcations I've been involved in (not exaggerating), some leasers treat their vehicles like disposable Dixie cups while others, myself included, use that 3 years to decipher if that particular vehicle is worth a long-term investment. Our 2006, for example, was first leased, then purchased. It passed the test

So bottom-line: my point was that a "recommended" fuel should be considered the default fuel whether you currently own or are considering the vehicle.

ek9lasting

The Acura Trainer that came to us, said specifically premium is no longer required, so I understand why the salesman stated that to his customer. "Rich people do not stay rich by blowing their money" they are conservative and watch where every penny that is spent goes. Yes they enjoy the luxuries of buying 45k plus vehicles but alot of clients break down every aspect of it especially when shopping with competitors. It is recomended to use premium with the vehicle, and if Acura is really concerned 5 years down the road non premium fuel effecting their engines they would have placed "required" instead of "recomended" on them. They want return customers and the typical loan is 60moths=5yrs where the typical trade cycle for individuals is 39-42 months. As far as leasing goes yes your average lease candidate isn't going to care because in 18 to 36 months they are already in a new one not concerned with how that engine is going to last due to them always being under full warranty. Yes I said 18 month lease because typically with the high residuals acura has, clients are able to get out early and break even. I am not saying that you should use 87 in it as I believe 91 is the way to go. However it is a question that comes up more often than you would think. Just my 2 cents. My question however is has anyone ran 87 and seen a decrease in mpg on a 2014?

F23A4

That is true...which is why I'll bet my 401k that most "Rich" MDX owners are probably driving around in an 04-06 model than any made afterwards. ....and they likely purchased it used.

Pinoy MDX

Good Information!
Thanks!
It is especially helpful here in Canada where V-Power Gas costs up to $1.55/Liter!

SmileyOr

I've read this on a number of forums when a decision of premium vs regular comes up. That small increase in engine HP is worth the price you pay over regular.

Ford chooses to advertise the Mustang V8 as 412 HP on regular gas. If you read the fine print the engine makes 420 HP if you use premium. That's a smaller percent increase in HP than you are suggesting you got, but the MPG can make up for it.

Timthetoolman

Recommended means that you have a choice that has some benefits as in more maximum power and possibly better fuel economy. When I ran a long test on a 2004 TL the mileage from premium vs regular was so close it was not clear if there was a difference. There may have been a power difference that could have been felt but I did not try to measure it. I rarely use the maximum power so this means little to me.

When towing with MDX with a travel trailer I will use premium but other than that I will use regular. At some point I may try the mileage test of premium vs regular to measure what difference it makes.

I keep cars a long time, 200k miles plus, when they are totaled or when vehicle needs/desires change. I see no reason why running regular would cause engine issues over 200k miles, if ever. There is no pre-ignition when timing automatically retards a bit.

Has anyone used regular fuel over the life of a car when premium was recommended had an issue? I did have one car that recommended premium and I did a lot of towing with it used regular and drove it about 165k miles and engine was flawless, then sold it after it was totaled from and accident.

If I wanted to have maximum total power I would measure the performance with both fuels and if premium made the vehicle measurably faster I would run premium.

Please chime in on real world experiences!

miterpa

Should you use regular in a 2014 Acura RDX ? For an answer turn to the online available 2014 RDX brochure "Facts" located in the Acura.com website under brochure. Look at the footnotes number 19 and 20. 19 states that it can damage your engine if it is below 91 octane. footnote 20 tells you that if you use 87 octane you get lower performance and gas mileage and that if you use lower then 87 octane it can damage your engine.
My conclusion is that 87 is ok but it will not give you the best of gas mileage. The engine warning non sense is given with both just to cover acura's fanny. Why would you even mention 87 if it was that bad to use anything lower then 91?
I plan on trying my new RDX on both 91 (premium) and 87 (regular) octane and calculating the gas mileage difference to see if it justifies the added 30 cents per galon. I agree with the Edmunds article that it is fine to use regular unless it is "required" by the Manufacturer.
I remember when Toyota and Honda claimed to void your warranty if you used synthetic oil because it could damage your engine, now they all use it. I used synthetic oil in my vehicles since 1982 and have gotten over 200K miles on them.

Majofo

Wow.. this thread.


In the simplest terms.. Octane rating is the resistance to detonating. The higher the octane rating, the higher the resistance.

What causes fuel to ignite you might ask?? Well duh, spark.. but did you know the cylinder compresses the space where the fuel and air mixes.. and did you know compression alone can ignite fuel. Ever heard of a diesel engine?

The higher the compression, the higher the resistance should be, otherwise pre-ignition / knock can occur. Knock and pre-ignition have occured on 92 octane in an 11:1 compression ratio engine. This gen MDX is a 11.5:1 compression ratio. Putting 87 octane in your tank is just asking for it.

You can use 87 octane, but as others mentioned, the engine will throw timing and push more fuel into the chamber to try to keep things in control. In some cases, it's not enough and damage will occur. You are also reducing your fuel efficiency so you end up paying more and potentially damage the piston, rings, valves.

Sure some nimrod will say he's been running 87 octane for 100k miles, no problem. You guys can also go fuck a bunch of hookers without a rubber and get lucky as well. But for every sucker who doesn't get crabs, I have seen many more that do (Justn).

Timthetoolman

Just about all the fear, uncertainty and doubt that I have read related to car damage and mileage is pure speculation.

Majofo--I have appreciated so many of your posts! What is your real world experience, test data, or something that I can sink my teeth into?

On the other hand I have very little time and miles with 2014 MDX, the type of driving currently is too inconsistent to take mileage measurements, and realize the direct injection/higher compression could be a game changer to collect useful data.

Can someone point to an engine failure post that could relate to fuel octane? What failure would this be?