I was just wondering what gas everyone uses. And the pro's and con's of that gas. Thanks!

 

i use 91 on my stock 88 lo3, i ran it with 93 for a while until gas prices went through the roof, and i noticed instead of there being no difference, the car actually ran a little better with the 91 octane, so I've stuck with that. I wouldn't even try normal, 87-89(depending on gas station) just seems too low for the 9.3 compression imo.

Also, the gas stations seem to very in quality as well, so shop around gas stations...I personally prefer Shell, I've always had good gas from them, though they tend to cost 1-2 cents more per gallon, its worth it to me.

 

I use 93 Amoco simply because it is the cleanest gas you can buy period. On a stock L03 with the timing at 0 degrees you would prolly be better of with 89 octane. If you advance the timing you want to run premium all the time to keep it from pinging.

 

Shell 93 baby!!!

 

87 shell or chevron

i run what is cheap, and adjust my timing to so i have no knock.

 

Is premium worth the money? hehe

 

it depends, the way octane works....

higher octane, is less 'explosive' it burns slower, that is why it works on high compresion engines without having to take out timing. the lower octane is more explosive, and that is why you typical have knock on high performance engines.

with our LO3s in factory form i never had a problem runnign 87, because we are pretty low compresion with conservative timing. in run 4* all the time on 87 and i never have knock according to winaldl.

with gas the bigger number isn't always best, you 'should' make as much or more power on low octane then you do on high octane, since low octane burns faster.

 

Its all about saving the money here. 87 octane rating so I can change those saved pennies to help my intake and exhust.

 

I run Sunoco 93. I tried out 89 and didn't notice a difference however I've got my timing advanced 4* and I like the piece of mind form running the 93.

 

91 chevron or shell, cant get 93 here in CA

 

I never have trouble with 89.

 

Shell/Mobil 93 octane! I have noticed a small diff in 87 to 93 not much but when i bump my compression up to around 9.5-10.1 i should feel the diff

SSBO

 

I run 91. Never lower than that.

 

Looks like lots of folks just like throwing money away, my car has NEVER needed more than 87 even after putting in a cam, heads and headers, I tried higher octane a few times with the same or increased timing at the track and didn't pick up anything.

 

exactly, read my explanation above, the most power you are going to make is on the lowest octane you can run without detonation. the only time you need higher octane, is if you detonate, and the computer starts pulling timing out.

 

Yup...guess I'm cheap too...

87 Octane CITGO or AMOCO....I normally use the same station.

that's a iron header L98 w/ some mods, 9.3:1 compression and timing is set at 10 degree BTDC initial. No knock, no rattle...and 20 mph AVERAGE to boot

 

93 Exxon

Or if im feeling adventerous 94 at sunoco

 

Exxon 93 since the day I got the car
I wish there was a Sunoco so I could try 94

 

87 Octane. As long as they didn't put water in it, I'm happy.

 

but the question is...

"is a stock 305 with a TBI considered a high performance engine?"

I don't think it is...

 

My owners manual says use premium and I have a 88 LO3.

And it pings badly w/ the lowest octane. I buy the highest octane I can get for Texaco, 76, or Shell. The highest here in WA is 92 or 91. I forget.

If your car will let you, use lower octane.

 

Yeah the other thing u guys arnt looking at is that higher octane burns cooler then lower octane and with higher compression, higher octane IS needed.

SSBO

 

i run 92 from speedway when i first got the car it was running on 87 but once in a while i would notice a very very slight ping so i added that bottle of the injector cleaner the one with the flame horse and it went away and i only use 92 all the time and maybe 89 when i cant dish out the money for 92.

it seems when i put in 93 it seems to take of slower.

 

93 octane, but I have added tons of timing. Probably mostly piece of mind, but sometimes the engine doesn't like it with 87 at WOT, which I assume is the ECM pulling timing. 25-26 mpg on the highway last trip, that's with 3.73 gears, AC, @ 70-80 mph and mid 14s in the 1/4.

 

hey guys


my maro doesn't like 87 it tends to ping @ 8* with the a/c on so i try to run 89. Also thinking about what you were saying about the car not improving over the higher octane gas i can understand that. i just filled up with 89 amocco and i was wondering why it felt more spunky down low. so i keep the 89 in it all the time and not waste money.

 

dewey is right....definately run the lowest you can without significant pinging or detonation, which should not be a problem on these tbi motors. i also have a volvo 850 running 12.5:1 compression....now that needs higher octane gas. my family has a history of working for exxon and designing cheaper ways to get gasoline transported.

 

87 Octane Gas

I have a 305 TBI......

 

I don't see why the owner's manual would say to use premium. It's an L03. It was put in caprices and trucks. If you can't run 87 with the stock timing, then you have a case of carbon buildup and should find a shop with MotorVac and have the service done. Or you can continue to waste money...

 

Whats MotorVac?

 

I have a 91 305 TBI, 5-speed manual Firebird with the timing set at 0° and it would ocasionally ping in 1st or 2nd gear around 1500 RPM according to WINADL (and my ear) when using 87 octane. I have since switched to 91 octane and the pinging seems to have stopped. The owners manual says to use 87 octane, but that was 150,000 miles ago.

 

Gentlemen, I present you with The MotorVac Thread

http://www.impalassforum.com/cgi-bin...33&t=002148&p=

There are 7 pages. Basically, keep reading until your skepticism goes away. Then, optionally, you may continue reading if your curiosity prevails (as it did me).

Enjoy.

 

Thanks for the info. Seems like some good stuff.