all my life i've been using 76 gas (i guess the whole "official sponsor of nascar" or whatever they had hooked me)...but friend of mine recently said to switch to shell because their gases can clean your fuel system (or something like that)...so now the question is...really?

 

All major gas stations will use these additives. Some just advertise it more aggressively. But, as far as one brand being better than another, I just stay away from and "mom + pop" stations, but even those should be fine. They are getting their gas from one of the major oil corps.

 

Gas is gas. Ususally it comes from the closest refinery, and they may put the additives at the refinery in to suit. If you don't believe me follow the gas truck around next time you see it filling the tanks. It goes from one station to the next - the gas doesn't care if the sign says Shell, Chevron, or Joe's. I just asked the guy who drove the truck, and he told me the story.

 

^ He is right.I deliver gas in Fl and all the gas no matter what kind of station its going to comes from the same rack.It might be a Shell rack,Citgo rack,Exxon rack,etc.But all the stores get the gas from the closest refinery and just branded under whatever name they want.The additives are mixed into the gas during loading.I think Shell has the best additive out there.My car runs the best on Shell.

 

There are some extensive posts on this in the Subaru forum. www.nasioc.com

Some very biased opinions on what fuel to use. I don't know the thread links, but search under "fuel mileage" or "best gas" or something.

I came away from the Subaru forum with the feeling most people recommended Mobil. Whatever. I use it.

 

The gas makes a minimal difference. I use shell, but thats mostly because I use a shell credit card and get 5% back on the gas which is about 13 cents per gallon.

 

I use Shell (91 Octane boo Cali sucks) also. My car seemed to pull stronger when I switched from Chevron to Shell.

 

Ditton on the gas all coming from the closest refinery its absolutely the truth, no matter where you are, its an agreement between the oil companies to save money on infrastructure costs. The only differnce is the addatives. Personally I like chevron 93 octane. I use chevron because my first vehicle was a 87 Toyoat 4-runner that my Dad was religous about putting chevron 89 octane gas in and ABSOLUTELY nothing else (he liked the fact that it has teflon in it). That truck has 178,000 on it, is still being driven daily by my aunt and has NEVER had any major engine work, the head gasket has been replaced once and thats it! Heh just for kicks we put that bad boy on the dyno, 84hp at the wheels :/ No wonder I wanted an EVO!

 

In Michigan the only place I know of to get 94 octane is Sunoco. That is what I use when I am in the neighboorhood. When there is no Sunoco around I get Shell 93. They both seem equally well, but there is something (if only psychological) about having the higher octane. In Michigan most all gas is "gasahol", that is, it has 10% ethanol blended in. There are a few mom and pop places that sell straight 100% gasoline with no ethanol. From what I have read, the straight gas should make more power than the 90/10 stuff, because gasoline has more energy per gram than ethanol. I have not tried it on a dyno, but I do know from my quad racing experience that using pure race gas (low octane Klotz, VP, Torco) with no ETOH, my engine does seem to run stronger. Just my 2 cents. Anyone else got some ideas on these topics?

EVOlutionary

 

By the way, the best gasoline to make max power is an oxygenated gas, with MTBE. They used to use it in most of the reformulated gas out west, but they found it is pretty toxic. I don't know if they use it in any pump gas out west anymore, but you can still get race gas with MTBE. In simple terms, it is gasoline with oxygen disolved in it. At low levels it runs fine in regular cars, but at higher levels you need to adjust the AF mixture. My only experience using it is in carbed engines, and in those you have to increase the jetting significantly. I do not know in EFI engines if the A/F sensor will automatically adjust or not. VP U4 (ultimate 4) is totally wicked stuff. When you are running it, everyone can tell by the sweet smell eminating from your exhaust pipe.

When I get my EVO reflashed for race gas by AL at Dynoflash I am going to use VP Motorsports 103. It is oxygenated and has a 103 pump (M+R/2) octane rating. Supposed to make about 5% more power than regular high octane race gas. Sounds good to me!

EVOlutionary

 

Evolboost,
I would have to agree with you on the Shell vs. Chevron in the bay area. I was putting in Chevron at first, thinking it kept the engine cleaner, then one day I put in Shell and it seemed the car revved/pulled a lot better. Thought I was crazy, but I guess not. Since then I tried 76, seems to be in between. However I was in Redwood City and tried the 76 100 octane mixed with 91 to make 94 and wow what a difference. But at $4.29 a gal. it is a once in a while thing.