wangdoom

I bought my S about 2 weeks ago, the previous owner told me he used 89 octane. Is this a really bad thing? What should I expect?

1a-race

I've been running my car on reg 87 octane for over 100,000 miles. Don't buy into that have to run premium gas story.

toucansam

For what it's worth, I found this link in an article from Car and Driver. It is a rating on gasoline from various vendors and the additives used. I don't know how reputable this report is, but it is a peace of mind in keeping your engine clean of deposits.


http://toptiergas.com/

Tugz_S2K

Guys, your OK to run a tank of 87, 89 octaine if needed. Running lower octain fuel will not damage or hurt your engine. These engines have knock sensors that will detect detonation or knock/pinging and will instantly retard timing to compensate. The end result is a slight reduction on power, and increased fuel consumption. Dont get too anal if you accidently put 87/89 octaine it wont hurt anything. Ex. 1a-race's Comment

As for people using higher then 91 octaine, unless your heavily modified, supercharged, turbo, ECU modified etc...your wasting your money. ABSOLUTLY no benifit to run 93,94,100 octaine in a stock or lightly modified (ex. intake/header/exhaust) S2000. Your Stock ECU is tuned to run on 91 octaine.

I personally fuel up at Sunoco and have choice of 87, 89, 91, 94.
I dont run anything else then 91. Even when running hard on the track, 91 works.

SheDrivesIt

Note to self: Don't buy used car from 1a-race.

SheDrivesIt

You own it now, you can't change the past. I would think excess wear would be minimal, but hey, who knows? Put 91 or better in it and drive it.

Remember, the engine needs to detect knock before it changes the timing. That means it has already predetonated. Now, this is probably no where near as damaging as letting an older engine without knock sensors knock. Honda recommends 91 or better octane (R+M/2). Just use it.

Tugz_S2K

Some just have no clue do they?...keep believing what you want.

http://www.usatoday.com/money/autos/2003-0...remiumgas_x.htm
Good Quote from a Honda R&D Chemist

1a-race

My car has been paid off for 3 years and has been downgraded to my beater car, I'm driving it until it's dead.

cthree

Good article Tugz. That's the plain truth whether people want to believe it or not. Running regular gas (87) is not harmful at 11:1 NA compression. Now drop 1 bar of boost on that and you could have issues (1 bar is one atmosphere of pressure, about 12 psi depending on where you live).

On a stock S2000 running regular 87 octane probably wouldn't show on a dyno and appear as normal variation. The ECU will map back the timing if it detects knock (that's IF not when). So long as the ECU can ratchet back the timing enough to compensate (and it can) there is no problems with it. It's not cleaner, more environmentally friendly, fuel efficient or anything of the sort; it's gas.

I run 87 in the wife's bimmer (the only place it says use premium is on the gas filler flap in a tiny sticker that is the same color as the paint (you need a reflection to see it). There is no appreciable difference in performance in her car as compared to 91. For the S2000 I use 91 mainly because I drive the snot out of it in very hot conditions and I always have (it's a habit).

SheDrivesIt

Ok, so a little sarcasm. You can roll your eyes all you want but I still feel it's bad practice to run low octane fuel in the car -- especially continuously. You believe what you want, I have my opinion. We can just agree to disagree.

And, I agree, interesting article.