yO

Ever since I bought my car, I've putting in 89 octane gas (silver at shell)

I know my ride only requires 87 but I've become accustomed to using 89 due to my other cars. Anyhoo, since gas prices are becoming ree-dik-u-lus would it hurt to go down to 87? I mean there is a five cent difference on each liter so I can sorta save some cash in the long run. Any thoughts?

Thanks!

Dyzee

No it wont hurt. As long as your engine dosnt ping or knock with the lower octane fuel you can safely use it without worrying about damaging anything.

imported_SiR_YO

I was about to say the same thing, but I'm such a hypocrite because I ONLY fill up ultra 94, and I know my car doesn't require it.. lately it's been $1/L and costing me over $40 to fill up everytime

that being said, I'm still stubborn and will not feed my baby anything less than that...

imported_BlazeInEk

Good for you! I am the same way. For all you Ultra 94 users....stick with it even though the hard times!

bbarbulo

iTrader: (2)

if your car needs it, then stick to 91+ octane. "high end" cars... like the SiR, Preludes, ITR, GSR, etc. But if you have a lowly Civic, don't waste your money. You're just fouling up your combustion chambers and cat-converters. Spare the motor.

yO

really b..... so it's coo to switch back down to 87??

bbarbulo

iTrader: (2)

not only cool, but preferred! you didn't mess with ignition timing, did you? only if you advance your timing should you run high octane. at stock timing, you should run 87. 87 gives you a much cleaner burn with less CO emissions (carbon depoits). higher octane will lower NOx emissions, but will raise CO. You want less CO though cuz that's what clogs exhausts, combustion chambers, coats valves, and fouls up O2 sensors. look at your spark plugs, what color are they? they should be a dull reddish/brown color. if they are black, it's because of your higher octane gas. now, after a month of driving on 87 check the plugs again. if they are reddish brown, then you're good. if they are shiny, then that's no good, means you have very hot EGTs, and need to go back to 89 octane. Also, right now, your computer has adjusted it's long-term maps for 89 octane. it'll take a little bit for it to learn that it has new fuel in it... also run some fuel injector through it, it can't hurt. I run FI cleaner twice a year for good maintenance... lube the pump and purge any water that may have condensed.

yO

Okay cool. I'm gonna wait until my tank is almost empty then fill up with 87 and add some fuel injector cleaner to it. Maybe just change the plugs for the hell of it as well. Thanks B.

j9chan

Bruno, what kind of FI cleaner do you use?

bbarbulo

iTrader: (2)

I use STP. It's the only decent kind readily available. I'd prefer Redline, but it's hard to come by. This way I go to walmart and pick up a 3 pack for like $10 or something.

coreyhayman

i run ultra 94 as much as possible, my car runs 10 times better with it and no pinging, my timing is advanced and iv got some goodies in my motor so she needs the higher octane

yO

So I just dump the whole thing in there? (I bought the STP one)

Also topped off with 87 today.

yO

Ever since doing this I increased my gas milage to about an extra 100km per tank.. Must have been the fuel injectors..

bbarbulo

iTrader: (2)

good stuff Untouchable

yO

hey b, you think I should change my plugs while I'm at it?

imported_fatredcircle

just check your plugs, if they look worn and the gap is off, then replace them. Heck, they're so cheap anyways

it amazes me how many people are mis-informed on fuel octane. 94octane is not needed for pretty much all cars excepted high cr motors or fi motors. i'm running 12.1:1cr and a 50 wet shot of n2o and i'm only using 91 octane, without pinging/knocking/detonation. Stop wasting the money on the extra 3 points of octane and use it to save for mods.

imported_Moe_Mentum

Its along the same topic, I just got a b16A JDM '98 swap, just wanted to know what the suggested octane I should be using with this car. Also about that pinging, what exactly does that sound like, never really experienced it.

dingus88

the higher the octane the greater the resistance to ignite..like in high compression motors lower octane is to volitile to be used with the added heat of the compression. THe more you compress air the hotter it get's which is how deisels work. I fou run high octaen you arent' gaining anything on a motor not meant for it. And Co emissions arent' carbon that's hydro carbons or HC's. Most of the usa only has 91 octane and that is fine for b16's and all the other vtec motors, save you money dont' waste it on 94 unless your turbo charged and want that little bit of extra safetly to detontation.

bbarbulo

iTrader: (2)

Untouchable, yeah, why not? If your injectors could use a cleaning, I'll bet the spark plugs could stand replacing as well. I do mine once a year, but keep in mind my car only sees about 5000 kms of driving each year. I'd recommend new plugs every 24,000 to 36,000 kms. They are cheap enough.

Pinging sounds like... just imagine a faint sound of two wrenches knocking together. Usually happens under high load, say 4th gear going uphill at 2000 rpm. 91 should suffice for a B16A, but every engine is diff't. Sometimes if there is enough carbon buildup in the combustion chamber to raise compression, you'll get some knocking. You can tune it by adjusting your ignition timing back a little bit or raising the octane. Also, come cooler spark plugs could help the problem. There are many different types of pinging, so don't get it twisted... there is detonation and preignition. Two different things, sound about the same I guess.