bigwavedave

The Corvette gets nice mileage because half of the V8 is shut down when at speed. That's something that is fairly easy to do with 8 cylinders.

Dimcorner

That and it's very slippery through the air.

techman707

Well, I'm glad to see everyone is now in agreement on what gas and octane is the best to use in their RDX.

ewynner

In my area (metro Detroit) the only gas is regular, 89 or 93. The salesman told me to put in 89. After a few weeks, no problems (like pinging). Any thoughts?

Dimcorner

Whatever you put in will be fine as long as it's not diesel or E85.

http://www.fuelly.com/driver/dimcorner/rdx

I have put 87 in the last 4 tanks and it doesn't ping. I am planning to switch to 91 for 4 tanks to see if there is a difference but I doubt it. It is my personal belief that if they pulled the engine off an Accord that uses 87 and stick it in the RDX with no increase in power nor torque then the map is the same since and advance in timing would generate more power and also make premium a requirement instead of optional.

Here the difference between 87 and 91 is $.40/gal.
I fill up every 10 days so about 16,000 per year or so. Car gets average of 25mpg so 640 gallons of fuel a year.

87 octane is about 2.30 here so $1,472.
91 octane is about 2.70 here so $1,728.

$256 dollars difference per year, or basically 2/3 of a car payment for me. Not much but I rather use $256 for something else.

texquad

I recently switched back to premium hoping to improve my mpg and it seems the opposite has happened. I'm currently avg about 18 mpg in mainly city driving. My TL is at 82K so maybe I need a tune-up? I love this car but getting 16 mpg makes me think about getting a gas sipper.

texquad

I forgot to mention that I also started over inflating my tires for better mpg too! 39/37

AcucaDude

I've been using 91 Octane (Premium) but I would use 93 if there were any gas stations in the bay area with it. I mean might as well spend some now than have to pay a fortune to fix later.

ipribadi

I think several discussions have been had and concluded that there are no damage risk of using regular octane gasoline in the 2013 RDX.
The 2013 RDX uses the same J35Z2 engine as the last gen Accord V6. The compression ratio value of 1:10.5, unlike other Acura engines, also indicate easy compatibility with regular grade gasoline

The real question up in the air is if this practice is worth while $$ savings if there is a mpg hit as well.

According to my experience (and several others) under light use there are no mpg penalties whatsoever.

Others have reported under heavier use (towing, mountain drives, aggressive driving) there is a slight mpg hit, some say not .. nothing conclusive yet.

backwoody

Hi Texquad, for better mpg, try to find a station that sells non-ethanol gasoline. I've found that pure gas (without the usual 10% ethanol) gives me about 10% better mpg.

Here's where to find stations near you:
http://pure-gas.org/index.jsp?stateprov=TX

Good luck; let us know how it works out.

Edit: forgot to mention - at highway speeds (65-70 mph) I'm getting 30 mpg+.

YeuEmMaiMai

Use the fuel recommended by acura unless it is not available and you need gas then use highest grade available. While you can technically use lower grade fuel, you will get lower power and ironically lower gas milage....

az99

This must be true since I read it on the internet.

YeuEmMaiMai

Engineers at Honda/Acura are smarter than you are. Now that we got that out of the way.....

sure you can run your engine on 87 octane but it is not recommended especially when the weather gets warm outside and the engine starts to ping.... the knock sensor only has so much control over the timing. (ask the 3rd gen TL guys about detonation in warm weather even with premium fuel)

19. Octane — RLX, TL, ILX, RDX, MDX, TSX V-6
Using gasoline with an octane lower than 91 octane may cause damage to the engine. Please consult the owner's manual for details.

so you pay $35 - 43K for a car and you are a cheapskate on gas? Do yourself a favor and buy a Honda accord or some other car that does not require premium fuel then you don't have to worry about it.

CoachRick

Yawn...does this apply to our last two $49k Volvos that ran just peachy on 87 octane? Yes, 87 min required, max performance from high octane fuel...sounds familiar.

YeuEmMaiMai

only to the idiot that does not read the Acura owner's manual....nowhere does it recommend 87 octane...

mickey513

Agreed.

Super unlead gas has always been required for Acura vtec motors since the early 90's.

*I know Honda SOHC vtec motors can run on regular unlead.

geocord

Page 263 of the RDX owner's manual:


Refueling
Fuel Information

■
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.

Can someone point out where in the above copied from the owner's manual where it says that 87 octane will damage the engine. My dealer's GM went to the RDX plant and was briefed by the actual engineers that 87 octane was just fine to run but COULD cause knocking and slightly less performance but would not hurt the engine. The GM stated this in a seminar for new owners at the dealership where there were many new RDX owners in attendance. Don't think he would say that if he wasn't sure about it. The engineers say it is ok to run regular as long as it's at least 87 octane. What part of that don't you understand. Are the engineers idiots too? After all, Acura warrantys the engines for 6yrs or 70k miles and I would think the engineers wouldn't have allowed that to be put in the owners manual if 87 octane would hurt the engine.

There is a big difference between "required" and "recommended" and auto manufacturers are very careful about the wording on these issues. Ford recommends premium for their ecoboost engines for top performance but clearly state that it is not required. Burn what you like as it's your choice but refrain from calling others names. It really makes you appear childish.

Acc20yrs

I agree 100% it is really a nominal fee when you think of how much you paid for the car. Good logic! I always use 91 or above and will continue to do so.

CoachRick

Just because I haven't typed it in a while...
1500 gallons/year for the two vehicles X $.40/gallon equals enough money to catch my attention...until EITHER vehicle shows any negative effects from running 87 almost full-time. Not gonna use crummy gas, not gonna use anything less than 87; but I got little reason to toss away $600 a year.

Doesn't matter how much the car cost...my $12,000 Miata wouldn't run worth a flip on 87, so it got the pricey stuff

ipribadi

Engine knocking depends on many factors.
Reason why high altitude locations may sell 85 octane and no higher than 91 octane is because the air is thinner (lower pressure).

For NA enignes, the lower air pressure prevents knocking to some degree (also lower power) permitting an even lower octane than listed in the manual without making things worse.

bluemike784

Looking at 2014 RDX. Reading post, I am looking at premuim vehicle because with 2015's being on dealer floors now the price isn't to bad and not much more than regular small suv's. But premium gas is anwhere from $.30 to $.60 a gallon more. Does RDX need/require the premium, what happens running regular 87 octane. (10% ethenol) What kind of real world MPG can expect with AWD model?

RDX2014Acura

I realize this thread has been around for awhile, but when I purchased my 2014 RDX in Feb 14, the dealer made a big deal that one can use regular in it. They stated that Acura recommends premium, but does not require it. My owners manual shows that premium is recommended, but it does not state that premium is required.

YeuEmMaiMai

besides the V6 and other little things like HID lights, they are pretty much the same

they share the same AWD system
they share the same cassis
they share the same basic suspension setup

They are just like the Accord and TL, same platform..

YeuEmMaiMai

the reason the TL requires premium has to do with how aggressive the tune is on that motor. they even have issues with 91 and high temps (they can get pre detonation). The CL type S also requires premium fuel but does not suffer from pre detonation)

also getting 273hp out of .3 more liters is not that impressive considering that they are getting 258 out of 3.2. This means that the tune on the 3.5L is NOT NEARLY as aggressive as it was on the previous engine. the

HP/L for TL is 80.6 for the RDX it is 70.8 down almost 2hp a litre. it may not seem like much but it is the difference between pre detonation and none.

Viveno

Really?? My dealership made a big deal the other way around, infact when I was purchasing the vehicle I was warned more than once to never use anything other than the recommended fuel. I was told people that used non-premium fuel had engine knocking and a whole lot of issues with the engine and that the savings are not worth it.


Also, I read the 2014 manual it says basically to use 91 otherwise if you use 87 your engine might get damaged...

Dimcorner

Like I mentioned before, the engine is the same as the previous gen Accord V6 with practically identical HP and TQ numbers and the Accord doesn't need premium.

I've had 16k miles mostly on 87 without any issues or knocking.

http://www.fuelly.com/car/acura/rdx/...mcorner/202971

Viveno

Nonetheless, the manufacturer states that we must use 91 octane. I'm pretty sure the people that designed the car know what they're talking about. So I'll take their word over an online forum regardless of how many PhDs any of us might have in engine combustion ....

Dimcorner

Because marketing department has nothing to do with the selling of the car and "Recommending" premium fuel in order to make the Acura brand feel more upscale...

Just saying, engine code is same, HP and TQ same, "Required" not stated in the manual.

Apexigsx

In my opinion do you have to use 91 octane or higher? No. Should you? Yes. I think the car is smart enough to adjust the timing in the event that you use 87 octane or 89 octane. Anything lower than 87 octane as shown below, and then you're asking for trouble. With this said, the car was designed to use 91 or higher, so in my opinion that's what you should be using.

This is kind of a touchy topic for me because I just don't understand the way some people think. Let's say premium gas is around .30 cents more expensive than regular unleaded, and you fill your car with around 15 gallons of fuel once per week. .30 x 15 = $4.50 more per week to run premium fuel over regular unleaded. In my opinion, if you're buying a 40k suv, you shouldn't complain about having to spend a little extra money on premium fuel.


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.

YeuEmMaiMai

because you stayed at a Holiday Inn Express last night?

CoachRick

No complaining here....but, two vehicles X .40/gal X 750 gal =
$600...more than a car payment. Until I notice a reason not to, I'll keep running mostly 87 octane top-tier fuel in both vehicles. Been doing that for years...and a couple of those vehicles were a lot closer to $50K than 40

ceb

There is a simple test. Run two or three tanks of 87 (to make sure that any higher octane is out of the system and keep track of "feel" and acceleration especially from traffic lights and on hills.

tank up with 93 once you are well below 1/4 tank and drive the same stretches. Take note of smoothness and that feel and acceleration.

If you note a difference then the 93 (or 91) is worth the difference. Note any differences in fuel economy too.

dedalus5550

This is posted elsewhere, just to get a range of responses/opinions.

Okay, had a weird experience. I was on the freeway doing something like 60--stuck behind a "slow" truck. I saw a gap in the next lane and moved over and gave it some gas. I didn't floor it by any means, and nothing I did was something that shouldn't be allowed or possible for any car. Anyway, the car started lurching in a weird way, like I was driving on marbles or even ABS kicking in. The engine light started flashing. I know now that this means a missfire and this makes sense. The manual says to turn the car off somewhere safe and let it cool for 10 minutes, then take it to a dealer. (I didn't see this until I got home.) I was close to my exit, and my house is just off the exit, so I drove it home. The whole while I could sense that it drove "off" and at the few stops on the way home, I felt like I had to put it in neutral and give it gas to keep it from stalling. I called roadside assistance and had it towed to the dealer the next morning.

The dealer took all day with it. But here's the weird part. The dealer called with the tech by the phone so they could ask some odd questions. What kind of gas do I put in it (supreme only, BTW)? Where do I get it (never thought of it, but usually wherever I am--most often at a chevron and a 76, the closest to my house)? When was the last time I got gas (about 3 days before)?

The second day, the dealer finally called to say that I could come get it. They said all of the codes were about fuel but they had no answers. It runs fine now, and it did the night of the problem when I started it to turn in around in my driveway. I asked about their odd questions, and the service advisor was adamant that it must be supreme. I told her that Acura "recommended" supreme but not required it. She "corrected" me to say that, no, it says "recommended" and that means required. See, I'm an English teacher and didn't want to get into a semantics argument with someone who was so convinced. Then the tech who worked on it happened along. He said it's well-known that Arco and Costco are not good quality and that Chevron is the best--the implication was that I need to stick with the more expensive chains. I guess that gas that costs less may be cheap in all kinds of ways, and I've heard plenty of "techron" commercials. But this was all news to me, and if it's that much of a problem, I think during the sales process it should come up. My car has 22K miles, but if it was just out of warranty, I wonder how much a day and a half of labor would have cost me. (And for the record, the last fill up was at a 76, and it was nearly a total tank of gas I got there. And it's extremely unlikely anyone was able to tamper with my gas cap and add something.)

Just food for thought.

Mike Todd

kjsand1

I was told by our salesperson that we could use regular for in town use, then switch to premium for road trips.
So that's what I've been doing since we purchased our 14 RDX AWD with tech.
In town there's plenty of ump and with the vcm I'm averaging 19mpg, when on a road trip and premium we achive 30-31 mpg.
If we need more giddy up I just select Sport mode in lieu of the normal D mode

Joe Las Vegas

How about not being a bunch of cheap *****!, use 91 top tier gas only, if anyone here wants to use 87 buy a Santa Fe.

Puma Jim

Yep, I will run 91 as required when I take delivery of my 16 RDX

Flipster23

iTrader: (15)

The salesperson is an idiot.

It says use premium fuel only, doesn't it?

CoachRick

Joe, Joe, Joe...why should I throw away $6-700 a year for more expensive fuel when both vehicles run just fine on 87? I DO use Top Tier fuel, I've just never seen any benefit to running 93(no 91 around here) vs 87 or 89. I don't lug the engine, don't run fully loaded and don't climb mountains. There is a solid forty cents per gallon difference(often more) at most of the stations around here. I really don't mind saving a full car payment every year by running good quality, lower octane petrol. Carry on...

CoachRick

Not anywhere I've read.

CoachRick

A) 'Supreme' is a marketing term...nothing more...at Chevron, it may refer to their highest octane fuel; but it means nothing outside of their stations.

2) The folks at Top Tier and Costco would like to have a talk with the tech supervisor at your dealer.(Can't speak about Arco...don't have those here).