Because I dont have a manual yet,what is the recomended oil weight,and fuel octane,mine is an 04

 

10w40 oil and i would rec using synthetic(mobil one). honda recommends
93 octane or better if u can find it.

 

Hmmm... I believe the S2000 should have 10w30 and should use 91 or better octane. BTW- I recommend synthetic oil too.

 

The correct viscosity is 10W30, NOT 10W40. It should also say it on you oil filler cap. 91 or higher is the correct octain as stated above.

 

If you live in a warm climate, 5W-30 is ok too....synthetic.

 

Octane rating varies between countries. Some (such as the US)use an average of research octane number and ......some other thing(MON?). Down Under we only refer to the RON.

In the US I think the correct fuel is 91 or 93? Here in Australia it is 98.

As mentioned before - 10w30 is the correct oil weight for an AP1.

 

10w30 goes for both AP1 and AP2. Synthetic is preferable, but not exactly required.

And yes, octane numbers vary around the globe. 91 octane is the minimum from NORTH AMERICAN filling stations.

 

thanks for the heads up on the oil viscosity. i usually have my honda dealer do my oil changes. i guess i should look a little more closely at my invoices. i figure they should know what viscosity to use, but i will specify next time, especially since they don't see that many s2k's. i'd like to be able to get 98 octane.

 

98 octane would be worthless unless you added compression (forced induction, higher compression pistons, thinner headgasket), so paying any more money for 93 or above won't help much

 

wouldn't cutting 91 or 93 octane with 98 octane improve combustion, especially since we now have that crap ethanol in our gas? just a thought.

 

I should point out that our RON 98 (eg BP ultimate, Shell V-Power) is the SAME as your 91 or 93 octane...just branded differently. Its like 62 mph = 100kmh same speed, different number.

There are various fuels and products to increase the octane rating of your fuel (eg racing fuel). Octane rating is the resistance to premature ignition of the fuel (detonation). Using a low octane fuel on SOME high performance engines such as our, the engine management will retard the timing to avoid detonation(pinging) and therefore lose power. Using the recommended fuel or above will avoid the engine managements need to retard the timing.

This does not mean you will gain extra power from your naturally aspirated engine. Running a higher octane fuel is popular on forced induction (eg turbocharged) cars. A higher octane fuel will let you advance the engine timing further (assuming you have necessary equipment to do this) with less risk of engine damage compared to running a lower octane fuel.

Higher octane does not mean better combustion.

 

kinda in away but it would really just be wasting your time. this is why i say that. A fuel's resistance to detionation is known as its octane rating. the octane rating is the primary benefit of racing fuels, in addition the energy contained per unit is more consistent, so jetting/injector duty cycles and other tuning measures are more predictable. Gasoline in general, both pump gas and racing, has about 20,000 British thermal units (BTU) per pound. the BTU content of a fuel is a measure of the potential heat a given unit of fuel can produce.Racing gas, because they are blended with less of the light ends that make for easy starting, have slightly more BTU than pump gas, but if you dont have the compression ratio of like 14:1 you will be just spending money you could have spent somewhere else.But you sure wont have to worry about detonation.[/

 

you are correct that the octane rating is based on the fuel's resistance to detonation and if you can do anything to insure your engine's running better, as in preventing any detonation, in the long run wouldn't that improve overall performance? i guess i should have chosen my words a little differently and nixed "combustion" altogether. then octane effects when the combustion takes place vs the actual burning of the fuel. would you say that was an accurate description in very simplistic terms? i always seem to confuse this octane subject and you have given a very clear explanation. thanks.

 

thank you matt

 

Maybe this will help explain things.

How stuff works - Octane:
Howstuffworks "What does octane mean?"

Avoiding detonation is always good in the long run. If your engine blows up, it sure won't be taking you anywhere in a hurry

Also, many high octane pump fuels (eg Shell V-power) also contain detergents within the fuel to help keep your engine clean. This has nothing to do with octane, but just another side effect from a better fuel. It is entirely possible you might find high octane fuel without detergents.

 

You don't need to put in anything more than what the car calls for. All octane does is reduce ping so if you only need 91 which is what an ap1 takes I don't know about the ap2. You don't need anything more all you are doing is wasting your money. I really don't care about the oil issue it's 10W-30 and I use AMSoil an I change it every 3K where as I put gas in it every 3rd day.

 

Yes the octane effects when the combustion comes in to play.The higher the octane the more of that gas can be compressed with out detonation taking place.So despite what some may think, lower octane fuel that is more volatile than higher.

 

let's put this subject to bed. thanks for the lively discussion. three more weeks to the start of spring.

 

I was speaking purely theoretically and do not intend to alter the fuel in my car.