also, just to throw my .02...don't run your gas tank to empty all the time. filling up when its about half of a quarter tank left helps save the injectors over time. you don't pick up the sediments sitting at the bottom of your gas tank.

 

IM gonna twist this thread somemore...


Why do you use 93 when 91 is adequate?
The stock ECU is tuned to use 91 octane or higher...
any more higher then 91 has no benifit other then a lighter wallet.

I can understand if you have an aftermarket ECU and/or FI

 

The ECU may retard the timing with 91 octane.

If your boss thinks your performance is "adequate" you are not doing too well.

"Adequate" meets the minimal accepted criterea.

 

Here in Australia, it goes like this...

Regular - 91RON
Premium - 96RON
Optimax/BP Ultimate - 98RON
Optimax Extreme - 100RON w/ethanol

Also, a lot of smaller service stations add ethanol to the Regular petrol. I was under the impression that ethanol, in time, clogs up your injectors, so I've always steered away from it. Also the same reason I won't touch Optimax Extreme. I use regular Optimax (98RON), but then again, my company pays for my petrol.

 

If the reccomended fuel is 91 octane why would the ECU be tuned to retard the timing?
You make no sense at all....

If 91 Octane is used, timing is nominal as set by the ECU. Why would timing retard?
Timing retards only if knock is detected. In a car that is NA or with a stock ECU, 91 octane will not prematurely detonate.

Explain your reasoning....thanks

 

Howcome the minimal recommended RON is 98 in Europe?
It say so in the manual and on the car itself.

 

Because that's 98 RON. In the US, premium gas is 91 (or 93) AKI

 

This has been discussed at length in previous posts. Until someone gets on a dyno and does some 91 vs 9X, there will not be a definitive answer.

However, the manual states a minimum of 91 Octane.

If your financial advisor told you you need a minimum of 900K dollars in your retirement portfolio, that would certainly not be your goal. So there are two ways to interpret the word "minimum". One means it is good enough, the other means barely good enough.

Some people have reported higher mileage and HP gains with fuel higher than 91, so without solid data, it just comes down to gut feel and butt dyno.

If you are familiar with the old vacuum advance systems, any time a car is under a load, such as hard acceleration, or going up a hill, the distributer will retard the timing. With modern Knock sensors, the timing is only retarded to the optimum point. It just seems to make sense that with a higher octane, the timing will not be retarded as far, thus giving you a little more HP with higher octane fuel.

I agree that under 90% of driving situations, there is no difference. For some people, squeezing the xtra HP out of the car is worth the xtra cost at the pump. especially if the car is not driven a lot.

What I find interesting is that the "91" number is the maximum octane available in CA (and maybe other states). This may have something to do with that number being chosen.

 

My point of view on this whole situation is Premium all the way. Me being an owner of a Toyota Supra TT have noticed and seen differences on Horse power because octane. My car on Stock Twins on 18 psi pushes 400+ to the wheels on premium but on Race fuel pulls 440+ depending on temp. That alone is proof to me that you can't go wrong with higher octane.

When i first bought my S....the dealership filled up my tank with 89 octane and Vtec......just didnt feel right.

Most car enthusiest want there car in best running condition possible pushin the most ponies they can get out of there car and dont mind spendin the extra money on a higher grade gas.

If your not will to pay for higher grade fuel on a Sports car then dont get one at all. Get something that Recommends Regular.

I in no way bashing anyone who purchases lower grade fuel...that's just my two cents on the whole topic. I know that gas prices range from state to state and sometimes it gets pretty pricey.

 

back in 1997 when accords start to have v6 under the hood my brother got one. started using arco 87 octane fuel. can't remember how much later but check engine light came on and dealer said it's got to do with our fuel. so he started using 92.

if you all wanna use 87 go ahead it's your car you are responsible of what you are doing who cares what other people use/cares. but personally i use only 92 and its recommended by honda.

i have question though. i don't drive my s2k very much. right now about once a week. and how bad is it to leave your fuel in your tank for long period of time? i am assuming its not that bad. since my tank is clean/new and only used one type of gas so far and it's sealed so it should be fine for awhile right? any thoughts?