RHCP0801

iTrader: (3)

i wouldnt do it, the gases(fumes) need some space in the gas tank too

dopes6070

iTrader: (25)

If you fill the car past when it clicks off you will fill up the vapor canister with liquid gasoline and over time it will damage it. Im supprised you havent gotten a CEL yet if you go till its almost gonna overflow.

Alpha 5

iTrader: (8)

NO CEL at all. I fill it up till it won't hold another ounce. I have done this every fill up. About 1 every two weeks or so for the last 3 years. No harm yet, that I know of.

Johnold

I have NEVER heard this ^ before!

dopes6070

iTrader: (25)

happened to my GF's car and they had to replace the canister for it to pass smog. The code was p1457? I believe

Alpha 5

iTrader: (8)

So other than the possible evap canister harm. Is there anything else I should worry about? I live in Oklahoma and we do not have to pass any type of emisions tests.

fightax

totally agree with sujak..my girlfriend does the same ****..lol i tell her the same thing..*smack.. lol jk xP

Johnold

Sujak - thats exactly what i do. or go to the nearest half dollar amount. so if i pump $16.24 cents, i just get it to $16.50 or 75 cents. i never put anymore than 1 extra dollar worth in my car. this is kinda scary to me finding this out in the first place cause i just bought an 07 Si and i've filled up the tank 3 times so far and i've done this "overfill" all 3 times so far. i'm hoping that i'm not doing much to hurt her

dopes6070

iTrader: (25)

going a little bit more wont hurt it... but going till it almost overflows can...

Got Boost?

My step-father is a mechanic and he had some input so he told me their is no gain to going high octane but he said a mechanics trick is to run higher octane through your engine for about a week or two for like a cleaning because believe it or not it is cleaner but the purpose of higher octane is a total different issue like for a turbo etc.

sl33pyriceboi

iTrader: (3)

^um........

gearbox

iTrader: (95)

its true, higher octane gas contains more detergents in the top teir program. but it is still not enough to matter, and certainly not enough to justify using high octane gas in a low compression motor. its much better to use something like lubecontrol.com in every tank. that actually works.

ronaldo9

iTrader: (6)

I'm probably the oddball guy here but I've experimented with all grades and 89seems to run the smoothest with my stage 2 cam. 87 runs way rich and I get no gas mileage like 280 to a tank on city driving. With 89 and 93 it bumps up to 320+. All highway I've hit 370-390 on a tank. Not sure which one makes more power I'll have to do some dyno runs with the different grades to really tell. 93 I ran leaner for some reason but it drove no better than 89 so I figured 93 was a waste even if I have no cat. Just thought I'd share my experience.

gearbox

iTrader: (95)

i believe one time is enough to do considerable damage that your car wont be the same again.

gearbox

iTrader: (95)

who? lol i believe the big guys are using hi octane unleaded.

EMK20a2

iTrader: (1)

^^^Yep 94 octane

Conspiracy Of 1

every so often i add high octane to my fuel, is this bad for it then.

ronaldo9

iTrader: (6)

No its not bad... the consensus through these 18 pages are that its a waste for our fairly low compression civics that run perfectly fine on 87. Gearbox said it all... use some fp60 or other lubecontrol products.

EMK20a2

iTrader: (1)

If you are really concered about keeping the fuel system clean then I would say use Shell gas, they all have adatives to help do this. The only reason I don't use shell is they don't have 94 octane, like Sunoco

red_civic_boi

i dont care wat people sayin but im using 87 till i get the turbo then i'll use 93 lol...