statboy

Premium gas is "required " for my 2009 MDX. What are the consequences of using regular or mid grade?

06cmv6

there is a reason for it..it only amounts to a few dollars at the pump even if you fill up...don't risk effing up your engine components by putting something less than the premium in it

Ken1997TL

You'll more than likely lose gas mileage as well, its not worth it.

cb4

The 2011 fuel flap says "required". It doesn't say recommended. The manual should tell you. If it says recommended for your particular year then you should be able to go with non premium but you will likely get less power. If it says required, well it's obvious what you should do.

moto94536

you can get away with 87 or 89. acura required 91. Acura get 300 HP from using octane 91.

If you care about high gas prices, you can use octane 87 or 89 from top tier gas such as chevron, texaco,conoco, 76, mobil, exxon, shell, so on.. it may probably 290 HP at peak RPM.. but who need it?

M3EP

I 've never driven on only 87 ,but on a few occasions used 89 and mix of 87/93. Never noticed lack of power nor pour MPG.

Aman

Car will retard timing to avoid knock, which might happen anyways, you'll see a reduction in fuel economy and power, and your car will just run worse all around. To top it all off, you won't actually be saving a noticeable amount of money.

ccannizz11

The short answer is, no. But every car is different, even within the same make and model, and it may change over time with your car. Typically, the older it gets, the less efficient it will be on lower grade fuel (assuming premium is recommended). I do this experiment on every non-high performance car I buy. I have never found a car (mine or anyone else's) pre-2003 MY that would be cost effective to drive on lower octane fuel. After 2003, it is still rare, as far as I can tell.


Here's my stats for our 2005 MDX:

Date Range: June 2, 2010 through August 18, 2010
Average daytime high temp: 94 degrees F
Conditions: Day and night; 60% highway 40% city streets, with one long trip on each type of fuel (almost one full tank used without stopping)
Fuel tested: 91 Octane and 89 Octane, purchased at various QuikTrips (guaranteed gasoline! may contain up to 10% ethanol )
Each type of fuel tested for 3 full tanks, with one tank of each fuel type used prior to beginning measurements.


Numbers:

91 Octane
Average price/gallon: $2.93*
Total cost of 3 tanks: 1-18.374 gallons ($53.65) 2-18.889 gallons ($55.35) 3-18.995 gallons ($55.85) = $164.85**
Total Miles: 1085.8
Avg MPG: 19.3
Avg cost per mile driven: $0.15182
Total cost extrapolated over 1 year: $1,743.50***


89 Octane
Average price/gallon: $2.83*
Total cost of 3 tanks: 1-18.448 gallons ($52.21) 2-18.987 gallons ($53.73) 3-19.112 gallons ($54.09) = $160.03**
Total Miles: 1051.8
Avg MPG: 18.6
Avg cost per mile driven: $0.15215
Total cost extrapolated over 1 year: $1,747.29***


Conclusion:

The difference in how far my dollar gets me on 89 Octane versus 91 Octane is statistically insignificant. Putting 89 Octane in the MDX serves no purpose other than to make me feel better at the time of fill-up.


*These prices are based on the number displayed on the pump at time of fill-up, added together and divided by 3. It is not based on the total cost and the total gallons purchased at each fill-up. This is for informational purposes. I don't care what my total average cost per gallon is, I only care how far my money lets me go.

**This is why people want to try 89 Octane.

***Using 11,484 miles driven from February 2010 to February 2011.

ichi d

if you are thinking about putting 87 in your mdx i think its time for you to trade in and get a CRV.

EL_PIC

Acura says 91 octane but also Prem required on fuel cover.
Note that ethanol will decrease octane and foul up your intake.
Its very easy to mix if you fillup with tank half empty.
One time use Plus and the next use Prem.
Here in Austin Plus is posted as 89 and Prem as 93 - reg is 86.

I think this is valid logic.

Note - the octane posted on pump is overstated !!!
Ethanol and methanol {if any state still uses it after they figured out it is cancer causing} decreases the octane.

Does anyone know how much octane is decreased with 10 or 15 % ethanol mixed in ???

Aman

Ethanol decreases octane?

Say wha?

Pretty sure ethanol is an octane booster. Or are you saying that the octane of pure gas in E10 or E15 is lower than it is in E0, since ethanol's higher octane makes up for it?

EL_PIC

Simple True but wrong logic.
Pure Ethanol is like 110 + but ...
there are many various types with differ numbers used in gas mixtures and when mixed with pure gas often causes a decrease in overall octane.
This is due to compatability, water, and phase content effects.
http://www.fuel-testers.com/gasoline...hanol_E10.html

Would like to hear comments from a real Chemical Engineering Dude ...

Aman

Thanks for the link.

Double_R

My mom has had an X5, ML500, and a GL550 and she has never used premium in them and has also never had any problems, so who knows... I put prem in my MDX

RACINGHART03

iTrader: (2)

I currently have a customer in with a 2008 MDX who has been using regular and I mean JUNK regular, and has burnt a valve. Please people, The engine was designed to run on Premium unleaded. It matters! If you dont want to put the correct gas in the vehicle, be prepared for the potential consequences.

moto94536

I think he will burn a valve even if he use No-Name brand ( preminum). The key is to use top-tier gas. In my opinion, acura can use octane 87 from chevron,texaco,shell, conoco,76,mobil .

EL_PIC

The truth is ...
you don't really what you pump in regardless of what advertised.
Gas additives are like what individual tobacco companies add to cigs.
The main gas players "also cleaverly marketed" as top teir might be more consistent but the addition of ethanol/other is an open variable.
Ethanol's downfall is water and it soaks it up rapidly from ground
and air {more problems with the wet high R/H areas}.
Water in your gas decreases HP, MPG, and increases corrison.
Learn from Brazil's cheap high sugar cane ethanol % and how it eats engines and gives poor MPG, HP.
I have been working with Shell Plus 89 and Shell Prem 93 at 50/50 mixes and it seems good.
But only $3.00 difference between plus and prem and a 20 gal tank.
When US ups ethanol from 10 to 15 %+... I will then use all 93 prem.