I'm 3 days from delivery of my 2005 S2000. I know this is a loaded question. I'm putting my flame suit on now.

I am fortunate to live in an area where I can get 100 octane pump gas at some obsene price. I can also get the standard 93 and sunoco "ultra" 94. The question is, will the honda like the 100 octane more than the 94? Is it worth the price of admission?

 

The 93 octane will work just fine.

Octane rating is how resistant the fuel is to heat/detonation. Higher octane gas also burns a bit slower.

Use what is recommended. Do not use less than 91/92. And no, don't bother with the 100 octane. It will do you no good unless your engine is knocking or detonation is ocurring. Which if the car does that stock, you have a greater issue going on.

 

93.

The higher octane rating is to reduce the possibility of detonation/pinging. While your car has a unique high performance engine, it will run the same at full tilt on 93 as it will on 94-100.

Now, if you were doing custom tuning and advancing the timing at certain RPM ranges...you could benefit from a "race" gas.

 

also moving to S2000talk

 

In California we only have 91, is 93 that much better or does it not make a difference?

 

Adding a higher octane fuel into a stock car is like retarding your timing. Your slowing the rate of burn (esentially delaying the combustion process). For the most power you want to run the lowest octance possible without detonation. So its better to run what Honda tells you to on the gas door.

 

you should use the lowest available octane rating that meets honda's requirements.

thus 91 > 93 >94

we only have 93 in FL. I wish 91 were available as it would be cheaper.

 

adding lower octane fuel would cause detonation, thus causing the ECU to retard the timing.

 

it seems like you've already got your answer but I'd just like to add that your question was a darn good one-- I myself had assumed that higher octane would be better-- so I'm glad you asked it. there was no need to don your flame suit IMO.

congrats on your 2005 S2000 and welcome to the site.

 

I've been trolling the forums since I test drove the s2k last wednesday.

Thanks for the info. I understand the whole concept of octane and detonation, I just didn't know if the S2K ECU and the VTEC bits would like drinking the rocket fuel better. I'm new to the whole honda thing. No mods for a while. I've been down that road in my Subaru.