Hi all

I've bought a black on black tech which will be delivered in January. I have a question on octane. I know you have to use premium gasoline with the RDX but does anyone have opinions on premium premium, ie above 91? Here in Canada, I only know of Sunoco that offers a 94. When I fill up my Integra (which can take regular) with 94 octane I definitely do notice it is more spirited and wondered if anyone had some feedback on performance by experimenting with gasoline with the RDX?

 

I would feed the RDX the highest the pump offers. I wouldn't get 107 points for the RDX, but I would do 94, if it was available in california; I always use 91.

For your integra, if it was a B18B1 motor, you wasted money; then again, if it was a B18C1/5, then the higher octane was the better choice for preventing knocking and pre-detonation.

 

94 octane in Canada ... thats awesome ... here in FL at the Sunoco gas station, we can get only 93 octane ... and most of the other gas pumps (BP, Mobil, Shell) I think their premium gas is 91 octane. Also recently, I have noticed a 25 cent to 30 cent diffference between regular 87 octane gas and 91 octane gas :-(

 

I like your comments and insights, but could you get rid of that annoying bug??

 

Modern cars adjust their operating parameters to run as hot and as efficiently as the conditions permit. With the turbo on the RDX there's definitely some advantage to running higher octane. The engine will adjust to fact that the timing can be further advanced without knock. I'm not sure if there's variable cam timing on the RDX but that can be tweaked to produce higher combustion chamber pressure if the ECU sees it's not knocking.

The ECU will rapidly roll back these parameters if you fill up with lower grade gas but will only slowly dial them back up once you put the better gas in again. They'd rather waste a little bit of possible efficiency gain than waste a whole lot of motor life. That said, you won't see much advantage from a single tank of super premium but after 2 or 3 you should.

Computers are awesome.

 

Octane higher than 91 on the RDX is okay, and you will feel the difference, as turbocharged engines thrive on octane.

But for your normally aspirated Integra... I think the "feeling of more power" is simply the fact that the engine is kind of worn out and it needs the extra octane to keep it running under proper operational parameters.
Don't waste money on using premium on NA cars unless the manufacturer requires it.

 

On the RDX I always pump 94 octane from sunoco (got a brand new sunoco station 2 blocks away).

Prelude (h22a4) requires premium as well but since its NA I pump 91 octane from petro or shell. (mostly petro as I get 4 cents off a litre )

What year and trim integra did you have? I believe there were a few different trims with different motors (Base, GSR, Type R)

 

It is a 96 SE (first year of what became the GS). Regular engine so it can run on 87 octane. But as I said when I compare running it on 87 vs 91 or 94 I can feel the difference. Sounds from these comments that it might be worth it to put the Sunoco 94 in the RDX tank. Guess I'll get a Sunoco rewards card. I think it's good for gas discounts, free car washes etc.

 

Smack it; it will dissapear.

 

I tried 89, 91, and 93 octane in my RDX. I can feel a noticeable power difference between 89 and 91, but almost nothing 91 and 93. I don't spend a lot of time near the red line, though.

 

Worn out engines make less compression so the higher octane shouldn't do anything for you. Higher octane fuel generally has less (readily) available chemical energy for the same volume of the lower octane. I don't know if it's a big enough difference in potential to have any real bearing in practice.

 

Is that from your butt dyno or did you put the car on a regular dyno and run several runs?

 

For people that live in western washington, Does anyone know if there are any gas stations that sell a higher octane than 91 in seattle, everett or anywhere in between?

 

I was referring to older cars requiring higher octane fuel because it was knocking and pinging. And it is well known that in such cases, using higher octane gas will help reduce those issues.

 

Oh, you mean like old big block V8s and such. I misunderstood what you were saying. I thought you were saying a car that used to run fine on 87 would somehow develop a need for higher octane.

 

You would not have "borrowed"that from someone on another board, would ya ???

 

I believe so.

H-T or B-F

 

And yes, I do see you at the other place.

 

Now at 50K miles, using 89 octane for the last 20K of it. No performance or mileage issues vs. 91.

 

I hope you don't have the turbo.

 

Do they sell an RDX that doesn't have a turbo?

 

Fishbulb your leasing or not planning to keep the car for long ?

Using octane lower then whats recommended (honda doesn't recommend 91 octane because they want to put more mullah in the fuel companies pockets) is just asking for problems. Please don't come on the forum and put down the RDX because it left you stranded because you couldn't put in the extra few dollars for 91.

 

No, I'll probably keep it for the next few years, at least - its pretty much my wife's car, anyway.

It'll be fine on 89. Most 89 pump gas actually tests above 90 octane, anyway. It doesn't get run very hard, and as I mentioned, no difference in performance or mileage. I'd be suprised if the knock sensor was actually in use.

 

Most of the Super is 93 oct. down here. It runs great on it. I'd like to try higher, if possible to find, just for grins.

 

Chevron has 94 here

 

You pay for 93 what we (well we pay more for gas in general) pay for 91 here.

Sunoco has 4 grades and each grade there is a couple cents a litre more. So you are getting a better deal and 1 octane is nothing (octane rating of fuel isn't to the exact T anyway)

 

I believe y'all have paid more for some time, but I think we're starting to catch up.

 

Hey, proudacuraownr -- most Western Washington stations have 92 as the highest grade, IIRC. Generally, it seems to be about 20 to 25 cents more per gallon than 87.

BTW, the few times I inadvertently used 87 (and a couple of times in Oregon, the station attendant filled me up with 87 -- Oregon has a dumb law, allowing only station attendants to pump gas), I noticed that I got at least 10% lower mileage. If you'd asked me a year ago if I thought that higher octane could pay for itself, I would have answered with a resounding "no way!" But I stand corrected. I always fill up with 92.