Hello,

A little while ago today I was at the gas station and asked for 89-octane gas. The attendant working there pretty much balled me out for using it, w/ the claims like "You're ruining your motor and pissing money in the wind". I just laughed and said "make it 89, or I'm going somewhere else". He wasn’t very convincing. I don't know if it was his outrageous claims of fuel economy with 91-octane fuel, or his huge misconceptions of what octane really does. Either way, he was a moron.

On the way home it got me thinking, "Am I using the right fuel?" I had used 92 octane for about 3,000 miles, but found some carbon deposits on my plugs. It was then I switched to 89 octane. My car runs the same, I don't hear any pinging, and my plugs look better... So why pay more only to have it result in carbon build up?

I thought I'd ask your options. Here's a pic of my plugs w/ about 6000 miles of hard use. The motor is a relatively stock b16a3 w/ 50,000 miles. It doesn’t burn a drop of oil and is in great shape. What’s your take on this?

(Please note that the "black" at the top of the plug was pretty much consistent on every plug, it just got knocked off from handling...)






[Modified by VR6T, 7:42 AM 2/19/2003]


[Modified by VR6T, 11:59 AM 2/19/2003]

 

They look fine IMO.

You should run 91 again for a while and then check the plugs one more time.. you might see a difference and be able to decide from there.

 

They look fine. What plugs are those BTW?

 

They're the Bocsh Platimum 1. I swapped 'em out for Bocsh Platimum 4. I can tell a difference.

 

Where do you get your gas? That sometimes can have a great difference in quality. I have been told by people that have researched this that AMCO and EXON are the best. Maybe you can try one of these, unless that is where you get your gas.

 

what motor?

Tom

 

A lot of people are under the impression that higher octane ratings burn "better." The octane rating # is a measure of a fuel's RESISTANCE to burning which is why it is needed in engines with higher compression ratios. Higher octane fuel (all things being equal) will actually burn leaner than lower octane fuel which could cause an engine failure if not used correctly.

We really only need enough octane to allow the engine to not knock or ping. I hear a lot of IT racers using 104 octane and such which is not needed in a fairly stock IT legal engine. Premium fuel (93 Octane Rating) is probably still overkill for an IT legal engine but I will continue to run this to be a little on the safe side.

Hope this helps

 

Where did you get that? We just recently had a thread about this, but the serach function seems hopeless to find it... so here goes again.

Octane rating is a fuels resistance to compression based ignition, not burning. Don't mix up burn rate with auto-ignition point, these are separate properties of a fuel. And the octane of a fuel doesn't have anything to do with describing whether the mixture is lean, rich or stoich, that's simply the ratio of air molecules to gasoline. Running any given octane cannot possibly change whether you run lean or rich.

 

[QUOTE]A lot of people are under the impression that higher octane ratings burn "better." The octane rating # is a measure of a fuel's RESISTANCE to burning which is why it is needed in engines with higher compression ratios. Higher octane fuel (all things being equal) will actually burn leaner than lower octane fuel which could cause an engine failure if not used correctly.


Where did you get that? We just recently had a thread about this, but the serach function seems hopeless to find it... so here goes again.


I think you are talking about this thread: https://honda-tech.com/zerothread?id=418720

There's about 4 paragraphs of good information right in the middle.

 

Octane is the fuel's resistance to ignition, period. Your fuel cannot differentiate between ignition sources. As such, it is a number reflecting the temperature needed for ignition. Now the spark from your plugs occurs at such a ridiculous temperature that any level of octane rating has no effect on the plug's ability to ignite the fuel.

However, a higher octane rating will slow the flame front within the cylinder. It's unavoidable. However, the picoseconds of difference between 87 and 93 octane are of little importance at any feasable RPM.

 

93 shell is all i ever use in my car

 

If your owner's manual says 93 then

If it says 87 then