geocord

I don't recall seeing anyone in here putting anyone down for using premium. It has been all the other way and you are the main antagonist. Why do you care? To my knowledge, you're are the only one in here that has had a bad experience using regular, everyone else that has used it has reported no problems. Telling people they should have bought Hondas is just obnoxious and you've said it several times. Personally, I just filled up with midgrade as that is what I always used in my Infiniti for ten years and it ran great. The RDX is running just fine....no rough idle and the computer says the MPG is running right at the same mpg as the tank of premium. I acutally tend to agree with you but find it offensive to see others put down if that's what they want to do.

I just went to a "new customer orientation" at my Acura dealer this morning. The owner of the dealership, who has been selling Acuras for 17 years, told us that using regular in the RDX will absolutely not affect the engine but you do get slightly less performance. He even recommended that if you do very little highway driving and do lots of short trips that it would make no noticeable difference at all.

Look back over some of your posts and you will see that anytime anyone says they are using regular that you feel obligated to jump in and put them down. Maybe you should worry about your own situation and quit telling others what they should or shouldn't do be it the gas they use or the brand of cars they should buy.

smarty666

Go tell it to somebody who cares feelings police!

I don't care what some joe smoe at an Acura dealership says, I'm going got go by what the manufacturer of the car states and my personal experience. Just sitting there telling me what somebody at some Acura dealership says doesn't make it right.

If you want to save a $150 bucks a year by putting regular in, all power to you. You can at least get the winter mat set with that savings.

AmberB

So my first few tanks have been manually calculated to be in the 22-24 mpg range while using 93 octane from Costco. The dash display showed 23ish the whole time.

I filled up on Monday with 89 from some no-name place as I was nearly out of gas. Premium was .30 more expensive so I figured I'd "save" a bit on this tank and try 89 instead. The dash now won't show over 20.2 mpg and generally is 19.x most of the time. I don't feel any difference in power, but this is either some shit gas from the no-name station or it makes a huge difference using 89.
Rough math based on dash display shows about a 10% loss in mileage...the "savings" at fill up appear to be entirely negated by the loss of available range on this tank. Not scientific, but I think this is a good data point....anybody else want to try?

I'm considering filling up with 93 at the 1/2 tank mark to see if the numbers improve immediately. I'm also thinking I should drive it down to empty and then get a fresh fill of 93. Can't decide.

CoachRick

A big key for me is the quality of the fuel. I'm sure Costco keeps an eye on quality, but the only way I'm using a 'no-name' fuel is if I'm about to run out and there's nothing else around. Running cheap 93 that doesn't have the 'proper' cleaning additives will harm performance and mileage in the long run, I believe. Our local Shell and Chevron stations have darned competitive prices vs the 'no name' locations. Perhaps we're just lucky. While I'm not interested in spending an extra 30 cents/gal for premium I don't 'need', I'm also NOT going to use a no-name fuel in order to save a nickel a gallon. YMMV and all that.

Bottom line for me...A)I'm running the 87 until I find a reason to switch and 2) I'm sticking with branded stations, especially those like Chevron and Shell who add cleaners over and above the minimum required.

Also, I never buy fuel when I see a tanker on the grounds...unless I got there first and can fill up before they start pumping and stirring up all the goo at the bottom of the tanks .

By the bye, filling with 93 after your tank drops to 1/2 or so will bring you to the 'recommended' octane level. If you actually observe an increase in mileage before the tank is emptied, I'd honestly be surprised. As I've mentioned before, I've done the 'tank of 87, then a tank of 93, then a tank of mixed' throughout the life of our XC60 T6 and now on our RDX and have NEVER found a measurable difference in mileage or performance. I absolute best mileage I observed in our XC60 was averaging 70mph on 87 octane Chevron.

AmberB

I'm with you on all your points really, just wanted to share my experience. It may be a bad experience due to the no name issue or maybe it's related to the octane...all I know is my RDX doesn't like it.

CoachRick

Good luck with the 'recovery'...hope it goes well. I need to fill up today or tomorrow and, unfortunately, our local TETCO Chevron stations are being taken over by Seven Eleven. TETCO had a nice 'rewards' program that got me some free goodies along the way IN ADDITION to the lowest prices around most days. Oh well, we'll see what changes are made. Fortunately, there are reasonably priced Shell stations about one mile in either direction from the neighborhood.

Back in Atlanta, we had Quik Trip stations selling 'their own' petrol, swearing it was 'top tier' and offering a warranty if you experienced 'fuel related engine failure' while using their fuel. Out here, we have quite a few chains of convenience stores, but I don't recall any touting their 'high quality' fuel. I'll just stick to the big boys whenever I can. Now that I think about it, Kroger grocery stores spoke highly of the quality of their petrol Discount for regular grocery customers and pumps at the stores. Pretty convenient and I never had any trouble with their fuel in the early 2000s.

smarty666

For the most part, I only put Shell in my vehicles. If I'm out a state, and can't find a Shell station, I will do Chevron or BP. But other than that, I stay with Shell.

About 5-8 years ago. I used to only fill up with Hess and Exxon gasoline. Switched over to Shell and almost immediately saw a 3-4 mpg increase in all my vehicles, which were from different automakers. Since then, I've kept with Shell and never looked back.

hawkeye62

Good thoughts. The major brands are likely to have very similar quality of gasoline. I would add Exxon, Mobil, Conoco, Sinclair, Amaco and Philups to your list of quality gasoline. And you may not know that some of the no name gasoline is actually made by some of the majors. And some of the major brands get gasoline from each other and from no name refiners in locations where their own supply is far away. The main difference between brands of gasoline is what additives are used. Since gasoline is a blend of several components made in a refinery most gasoline will have very similar chemical properties. Gasoline does change from summer to winter, and using a winter blend in summer or the reverse can dastically affect the way your car runs. And dirt or water in the service station tanks can result in big problems. he stations are supposed to have filters to remove dirt and they are supposed to pump out accumulations of water. Cars also have fuel filters to remove dirt but water will cause serious problems. Most auto parts stores have stuff you can put in the tank to get rid of water. (Usually alcohol which will cause water to dissolve in the alcohol, which mixes with the gasoline.)

My own preference is to use premium gasoline because of my knowledge about the various components that go into gasoline. I believe that over the long term, an engine will stay cleaner and cause less problems if premium fuel is used. For someone who doesn't put 100,000+ miles on a car, It won't make much difference what quality fuel is used as long as you are satisfied with the octane.

My two cents, Jim

weather

Jim...I agree with your post above. We have the same situation here where I live. There is one refinery in NB and one in NS. All stations in NB (regardless of the banner they sell gas under) gets their gas from the same refinery. So whether I buy Shell, Esso, Irving, Costco or any other brand, its all the same. I will make sure I get the best price, best reward program and best Octane so for me at the moment, that means one place only...Costco with their Supreme grade

skzekeman111

OK, in order to attempt to settle the problem of
1) does using 87 or 89 octane (when 91 is required affect) engine performance
2)does using 87 or 89 octane (when 91 is required affect) cause engine damage

1)Let us state the year and model
2) the octane rating of the fuel used
3) the number of miles driven
4) the mpg if known
5) whether there was engine work done and , if so, after how many miles driven.

I know this isn't very scientific, but may give a qualitative answer to the problem, and the reader can then draw his/her own conclusions

In my case:
99 tl
89 octane
mostly highway driving
199,000
23 mpg average
regular maintenance, no engine issues

AmberB

UPDATE
I filled up with 14 gallons of Shell 93 octane yesterday. The dash display was back at 24 MPG within a mile of the fill up. This is an interesting development as it validates my experience with "that tank of gas" as being related to "that tank of gas"... not weather, traffic or vehicle malfunction.
My next objective is to again fill up at Shell with 89 octane and see if the mileage drops again. That should tell us if it's the quality of the no name gas or the octane rating that caused the difference.
One additional point...I noticed that the cylinder deactivation/lugging feeling I experience when driving nice and easy didn't occur much on that tank(or for long duration when if did.) The extended lugging is back now with the 93. I think the engine is prevented from using the cylinder deactivation while using lower octane gas. It drove just fine, just got less than optimal mileage.
My last car was a 3.5 V6 and it got 19-20 mpg. The RDX is also a 3.5 V6 that seems to get 19-20 mpg when the cylinder deactivation doesn't operate. Makes sense to me...
Here's my hypothesis...since the difference in cost between mid grade 89 and premium 93 is about 30 cents, it's roughly 10% less expensive up front to use mid-grade with the trade off being about 10% less range on the tank.

geocord

Was at a Shell station a few days ago and filled up with midgrade. Reg was $3.54, Midgrade was $3.74 and Prem was $4.15. That's a .61 difference between Reg and Prem which is 17% higher. I noticed a huge spread at another Shell station like this a few weeks ago and thought it was just that station gouging on midgrade and prem. Maybe they are owned by the same franchisee or something and is just gouging us locally. I'll have to seek out Shell stations further out from my area and see.

GRDX

The thing is the price of gas is falling every time they take delivery. The station has to sell the gas at a price that covers what they paid for it. Therefore you will see prices for gas lower at high volume stations while lower volume stations are still selling older higher priced gas. Since most people buy regular the premium in the station tanks is older and higher priced. That is the main reason for the larger price difference.

weather

^^^ GRDX....And I am sure that if the price on the oil markets starts spiking, they will hold out and make sure they give people the discounted price they paid when the delivery occurred right I have such a bad taste in my mouth when it comes to gas prices and how we are gouged every way they can. Funny that they always use the famous "supply and demand" but when a hurricane heads for a coastline and people hit the home improvement warehouse to buy wood to board their windows, the government will crack down if the warehouse raise their price....Is that a supply and demand too? Why is it OK for the gas stations to raise their price at the pump before a long weekend because they anticipate a higher demand but its illegal for other markets to do the same...rant over *grrrrr*

On a positive note, our regulated gas price dropped about 5% today (8 cents/litre or about 30 cents a gallon)...government sets the maximum gas price here where I live, but luckily, there is no minimum gas price, but my friend mikejmack lives in a place where they do. This means that we can see price drop based on competition and Costco gas bar helps drop the price even more here.....

dedalus5550

I remember the day Iraq invaded Kuwait. The exact day, before we heard the news, we passed a gas station and couldn't believe the price. Can't remember the exact price or percentage jump but it seemed like a practical joke. Now if that gas and that oil was obviously bought long before that day--why the price spike? News or even a rumor and they run outside the station to change the price. When the crisis passes or turn out to not be anything they take their sweet arse time about reducing prices. My favorite suggestion for combating this is everyone agrees to shop only one national chain. We all buy only brand x at whatever they charge and the other guys have to start dropping their pants.

hawkeye62

Hey guys, I would rather have the current oil companies running the oil business than any government. The government: the efficiency of the post office, the cost control of the pentagon and the compassion of the IRS.

Jim

geocord

That's just ridiculous. And I suppose they only fill the tanks when they are completely empty too so they have a clean break on "old gas" vs. "new gas". The two Shell stations I referred to could not be more different. One is downtown is a very small suburb with about 4 or 6 pumps. The other is near the expressway with probably 16-20 pumps and a car wash and convenience store. I would guess the big station sells four to five times the gas the small one does. Prices are the same with the same price spreads between grades.

mikejmack

Ours went down 10 cents per litre this week. The "interrupter" clause went into effect Wednesday night and then it dropped another 5 cents this morning. I think it is still cheaper in your province. When I travel I always make a point to fill up in your province just before returning to mine.

GRDX

No it is not ridiculous. It is economics 101. Imagine a new station opening with a 10,000 gallon regular and a 2,000 gallon premium tank. They are close to the distribution point so they can get delivery on demand and can wait until one of the tanks is near empty. They have to charge $0.05 a gallon to cover expenses to make a profit.

The first delivery regular costs $3.80 so it is sold for $3.85 and premium costs $4 so it is sold for $4.05. The difference between regular and premium is $0.20.

Now the regular is almost sold out so a delivery is ordered but there is still 1,000 gallons of premium left. The price dropped. Regular now costs $2.80 so it sells for $2.85 and premium now costs the station $3 but they can only buy 1,000 gallons because they still has 1,000 gallons of premium in the tank.

1,000 gallons bought for $4 equals $4,000 cost.
1,000 gallons bought for $3 equals $3,000 cost.
Total cost for the 2,000 gallons in the tank is now $7,000 cost. Do the math the total cost incurred is now $3.50 a gallon. Premium will now be priced at $3.55 a gallon. The difference between regular and premium is now $0.70.

Of course there are a whole bunch of other factors I am not going to get into which can influence what is actually charged whether at higher profit or even sometimes they sell at a loss. This should help in understanding why the price does not fall right away when the prices are falling and the increasing gap in prices when they do.

Why doesn't it work that way when the prices are increasing? They raise the price instantly when the price is going up even though they paid less for what they have!!!

Well, one reason is they have to pay for the gas when it is delivered. Since they use the income from the gas sold to pay for the gas bought they raise the price so they have enough scratch to pay for it. You see this with the independent retailers. Big oil is not affected the same way so you will see company owned stations rise slower.

geocord

Appreciate the lesson in cost averaging but I think when you say "there are a whole bunch of other factors I'm not going to go into" kind of paints the picture. I think the "whole bunch of other factors" have a lot more influence on what is charged than the actual cost. Like.....what the market will bear.

GRDX

I would think "what the market will bear" has more to do with what the supplier charges the station or what the station charges regardless of grade. We are talking about the unusually large difference in the cost of grades. Stations are lowering the prices to keep up with the competition. Too high people will go elsewhere. No sell no profit. Are you suggesting they are lowering the price of regular because the economically disadvantaged will buy it and if someone wants premium they can afford it so screw them?

geocord

No, I am not suggesting that and that is offensive to say the least. You're getting ridiculous again. Stations around here usually post only the Reg price on their signage so that price is therefore pretty much the same in the same locale. However, and this is what was talking about, these couple of Shell stations are charging a lot higher for Mid and Prem versus the lower tier stations that are about .15 and .30 above Reg respectively. These two Shell stations were double that. Now, it certainly appears they are getting people to swing after they see the Reg price is similar to everyone else, only to discover the Mid and Prem prices are crazy high. That's what happened to me. The reasons behind it may be the cost theory you threw out(doubtful) or they may just be trying to make an extra buck. I think it's a little deceptive since just about everyone expects the price difference to be about .15 and .30, not .30 and .60. At that point you can bite the bullet and pump some expensive gas or put the gas cap back on and drive to a different station. Human nature being what is they have probably figured out that most people buying Prem just grumble and pump anyway. Ergo, more profit and they appear just as competitive to the discounter down the street with the same price for Reg.

GRDX

OK I could see where them only posting the Regular price as viewed from the road leading you to that conclusion.

The no name gas grade price spreads are similar in my area as yours, however, if I look at two top tier stations by me... one down the road from the other, both independently owned and both cash or credit same price.

Exxon 3.39 3.79 3.89
Shell 3.45 3.79 3.89

Exxon posts all three prices for all to see in any direction.
Shell only posts one price (Just like your area - must be a Shell thing) Regular 3.45. They are not playing that game around here or they would be selling Regular for 3.39 to match Exxon and then Mid-grade and Premium would be higher not the same.

AmberB

I'm using gasbuddy.com to report prices in my area so you two have data points to base your arguments on...

Speedway 3.39 3.49 3.59

Mobil 3.39 3.52 3.65

sam's club 3.29 0.00 3.68

shell 3.39 3.54 3.69

road ranger 3.49 3.60 3.72

thorntons 3.47 3.67 3.77

phillips 66 3.49 3.66 3.78

bp 3.47 3.62 3.82

let me get some popcorn now...

GRDX

Good Idea! I'm going to go make myself some popcorn too. I'm pretty much done with this discussion anyway and once I start on the popcorn I wont be able to post back anyway. Don't want to get my keyboard all buttered up :-)

CoachRick

Don't forget, 'he' insists that the margin is always .05/gal at the same time those 'whole bunch of other factors' figure in. Heck, this must be easier to understand than I first thought.

Shahryar

We picked up our 2013 Acura RDX AWD Tech last week. 10h33m/315 miles into ownership, just filled up for the first time. Read through this entire thread first and decided on regular 87. Closest gas station to me is 7-eleven. Not sure if they count as "no name." Seemed points were made on both sides but ultimately, I didn't see a killer point to justify the extra $0.30 per gallon.

Just to comment on some of the thoughts on the money part of this: I filled up almost 15 gallons in about a week. this was a pretty usual week with our driving. that's approx $5 a week in savings, but rather than savings, I'd prefer to view it as $5 "not wasted." Even if I have a $40k-ish car, still no reason to spend unnecessarily.

Sometimes for me, it helps to look at the extra money spent from the receiving party's end. Specifically how nice it is to receive money for potentially nothing, but just because "I might as well." Knowing that the extra few bucks they got off of me and multiplying it by hundreds of people, or thousands, or millions makes me realize someone's getting rich off my unnecessary spending and that bugs me.

So that's my thought process. More than willing to spend the extra if I know it's a guarantee I'm getting something worthwhile out of it but I need proof first.

Shahryar

A little o/t, but regarding the Mobil 1, shouldn't that oil be good for at least 10k miles? you can have a used oil analysis done from blackstone to confirm. That's what I did when I had my '08 IS 350. It was determined From the test that at 12k miles, I was starting to push the oil, but if I had changed the oil filter in the middle of the oil interval (6k miles) then I should have been fine.

I get the better safe than sorry approach but no point in wasting good oil, wasting money, burdening the environment, etc

dcpc08161992

***

I know some insists on premium but RDX uses Honda Odyssey's and Accord V6 (right???). That V6 (unless they heavily modified it for the RDX) should be okay to use 87 octane. I think they recommend premium for perforance purposes.

I don't drag race, I don't floor the gas, I don't ever drive over 80 (Okay, I did sometimes on the alonely highway), and I certainly can't feel the difference between using 91 vs 87 octaine gas.

I don't know, maybe I am wrong and ended up messing up the engine but it does say 'unlead gas/premium recommended' so regular unleaded should be okay.

I will treat my RDX to a premium when I know I will be racing downd the road on a long and lonely stretch of hightway.

Colorado Guy AF Ret.

I know this is a "hot debated issue" on most sites. I burn 91 and I'm getting outstanding fuel mileage and have the performance there whenever needed. 87 is not a premium fuel. If you can find 89 I would try that....but, for me, the little in savings is not worth going against the recommended premium that Acura prescribes. Long term use of 87, and the slight preignition that will occur over time can and will damage the engine.

The timing is different in the different "similar" Honda V6 engines. The engine mapping is different. I had a '12 Accord Cpe, V6, VCM engine. Almost the same hp and torque....and I could burn regular...but, these engines are not exactly the same. Acura is a division of Honda, obviously...and Honda Motor Corp. doesn't have any skin in the game for us to buy premium fuel. They recommend it for a reason. The engine is mapped and timed differently than the Honda V6's...and thus run better on premium.

So, if I had 89 available I would try that....and save yourself a couple bucks....but, to me, if I can afford this vehicle I can afford a few extra bucks for premium fuel and I won't have that little guy sitting on my one shoulder whispering that I may be hurting my engine in the long run. I drive with no worries on my premium....hot dog it when I want and again, I get great mileage. Almost 30 mpg on a 120 mile round trip....and always get between 22 and 24 in town only driving.

AnyaBoo

I 100% agree with your post. I bought a 2012 Acura TL 3 weeks ago and I plan to only use 91 Octane fuel because it says under the manufacturer specs not doing so will damage the engine. Comparing the Acura engines to Honda engines that require 87 Octane is not a good assessment to make. In 2001 I bought a 2001 Honda Prelude new and it required 91 Octane because the engine performed differently.

Shahryar

I see where you're coming from and if you're not driving very often, then yeah, it could be a matter of a few bucks. But If I'm gassing up weekly, that's $5 a week for premium over regular, $250 a year..

I feel the long term benefit of the engine by going with Premium over regular is more of a feeling but not set in concrete. Whenever this engine fails as a result of this gas choice, how many years down the road can it be.. 6? 7? 10? multiply that number by $250 is how much I'd have saved so far w/ my gas decision.


I have that guy too. I'm sure we all do. But on the other shoulder is the little guy who's always nagging me if I'm wasting money. Worse, is there someone out there who's getting rich off of me by this "wasted" money.

Now all that being said, the mpg benefit could be easy to figure out and quantify to help determine if premium is worth it. But I'm not finding clear answers here either.

Great discussion here. Looking forward to hearing more thoughts and hopefully seeing some clear answers

Vividsi

I would run premium all the time and if I was ever in a situation where regular was the only choice then Id know I would be ok.

CoachRick

Respectfully...
This is part of the difficulty of this discussion. There is premium quality and there is the perception of a 'premium' octane. I believe plenty of the branded fuels are indeed 'premium' quality at all octane levels. Chevron, Exxon, Shell, and many others fall into this category, I believe.
89 isn't 91...not sure it's any better for purposes of this 'experiment'. IF 91 is what is needed, 89 wouldn't be the answer.
IF you have documentation to back this assertion, then I believe the discussion is over. IF it has been documented that 87 will damage the engine, I don't believe any of us would ignore that so we could justify risking a multi-thousand dollar engine in order to save a few hundred bucks a year.
This may or may not apply, depending on how one drives the vehicle. Some people report a 1-2 mpg increase with 'premium'...I've never noticed that with a half-dozen Volvo turbos and now with the RDX. I've also never perceived an increase in 'performance' with different grades, but not many of us push our engines to the max so that we 'might' tell a difference. An exception might be folks who are climbing mountains or towing at full capacity on a regular basis(OR running 1/4 mile times during their daily commute ).

AnyaBoo

If you go to any Acura dealer site or even myacura.com it says the vehicle requires 91 Octane and not doing so may cause engine damage. I would not want to void my warranty by not following the rules.

geocord

I'm sorry but you are just plain making stuff up. Below is a direct copy from the online myacura RDX owners manual.

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


I don't see "required" in the fuel recommendation. Manufacturers are very distinct when they use the terms "required" and "recommended" in their fuel guides. You will also notice that is says using less than 91 octane CAN cause occasional engine knocking and affect performance.

It also says using LESS THAN 87 octane can cause engine damage....not 87 octane. Heck, I don't even know if there is less than 87 octane available anywhere.

This information is from the engineers that built the engines so I will rely on them. Some people say "Well, if you can afford this car than you can afford the extra for 91 octane". I don't know why they say these things as they certainly don't know anyone elses personal situation. Why can't they just say they use 91 octane cause they think it's better and quit trying to convince others with phony info, half-baked assumptions or scare tactics. I know, somebody will come back with "wow, what's the big deal". That's fine, it's just frustrating that there are so many people that tend to think they know more than the engineers that made the engines do. Believe me if using less than 91 would damage your engine, Acura would say "91 Required" not recommended. They warranty your engine for a long time so they have a lot of skin in the game.

AnyaBoo

I sorry but when it says, "Use of gasoline with a pump octane less than 87 can lead to engine damage", that means it is required to me.

You can do what you want with your Acura but for me, I care enough about it to use the recommended Octane 91 fuel as well as premium gas that uses detergents to prevent engine build up. I paid over $35,000 for a luxury sedan; therefore, I am going to pay the extra amount for premium octane 91 gas.

AnyaBoo

I should also mention in the 2012 Acura TL owner's manual it has the fuel recommendation under under an index with the title, "Fuel Requirement". And in the section it states:

"Your vehicleisdesignedtooperate onpremiumunleadedgasolinewitha pumpoctaneof91orhigher.Ifthis octanegradeisunavailable,regular unleadedgasolinewithapump octaneof87orhighermaybeused temporarily.Theuseofregular unleadedgasolinecancausemetallic knockingnoisesintheengineand willresultindecreasedengine performance.Thelong-termuseof regular-gradegasolinecanleadto enginedamage

Unfortunately, when I copied it from adobe reader on my phone, it put no spaces in between the words but I am sure it is readable.

You can use what you want, it is YOUR car but I care about my car too much not to follow the follow the recommended guidelines.

AnyaBoo

Oh and your quote inaccurate. Your quote states that long term use of less than 87 octane can cause engine damage, when IN FACT, my owner's manual states "long term use of regular grade gasoline can cause engine damage. In the earlier sentences, it defines regular gasoline as 87 or higher (but below 91) not less than 87 octane. 87 octane is only supposed to be used temporarily if 91 octane is unavailable.

Shahryar

wait, why is the 2012 TL manual being cited? perhaps that car has a requirement for premium but we know for sure the 2013 RDX doesn't and is a different car.