djserumsrq

I typed "TOP TIER GASOLINE" in yahoo and it gives the companies like Shell and Chevron that use more detergents in their gas (Which i'm told is better for engine and valves) I switched from Hess and Racetrak to SHELL and found a very slight savings per gallon (maybe an extra mile or 2 per gallon, but that was also with shell 89 oc) I Drive an 06 Mazda3 5dr . Despite my research i havent found ANYTHING to suggest TOP TIER is better than anyother gas, sure it has more detergents, but are ALL the detergents used good, Some maybe more corrosive or worse for the CAT...so i'm still searching for the answer too!

Rusty

I think you need some detergents to keep the injectors clean. I just use brands like Sunoco, Exxon, or Amoco. I stay away from Hess, Citgo, etc. And don't buy gas while the truck is filling the station's tanks, 'cause you'll get all kinds of crap in your tank.

djserumsrq

Out of curiosity, and b/c i live very near a Hess and a Racetrac...but usually go outta my way to fill up with shell which seems to give a mile or 2 more per gallon than Hess or RTrac...Do you hear a lot of bad stuff about Hess in particular? Hess seemed OK but when i started going to shell i did notice a slight better diff. and Where does Hess get their gas, anyone know? Cause I've always been curious, b/c a lot of people equate nice stations/ and big store with great gas , when really its all a warm and fuzzy farce...Thanx for any info

Rusty

I've always thought Hess sucks. I don't know that, it's just my opinion. But it seems like I've always gotten poor mileage with it. And when I run a carbureted engine, like my 396 on Hess, the the throttle plates and venturi get coated with varnish faster than with Amoco. Amoco has always been my favorite, but they're affiliated with BP now, so I don't know. I'm leary of BP because they used to be Gulf, which was the gummiest crap I ever used.

micdmac

meGrimlock, you're correct. As a chemist, I can assure you that gasoline and water don't mix. Gasoline can not be "watered down" and the ground water that we drink will not soak up large amounts of gasoline. In fact, the additive MTBE which improves emissions was taken back out of gasoline because it dissolves in both oil/solvent based fluids as well as water based fluids. It was polluting lakes, rivers, and ground water.

As for brands of gasoline, I ususally buy the cheapest which is an Arco owned by BP. It is also right on my way home. It never makes sense to go out of your way to save money or to get gas that you think gives you slightly better mileage. All gasoline comes from the same place. The smaller companies are simply buying gas from the main producers. So, the main differences, as stated earlier, are the additives. I can't say I've studied this, but they seem unnecessary and here's why.

Pure gasoline is a solvent and by the time it goes through the pump's filters and the fuel filter on your car, there should be no solid impurities. Once it ignites in your engine, it produces CO2 and water vapor while leaving behind some uncombusted gasoline because the reaction is not perfect. These exhaust materials all get sucked away as gases and the unburned gasoline should get ignited in the catalytic converter. So, it seems like a pretty clean system. However, the gas companies say that your engine will build up sludge, but they never say where that comes from. Giving them the benefit of the doubt, detergent additives could help get rid of sludge by helping the gasoline dissolve more material. It is basically like adding soap to water to wash your dishes. However, this also means you could be adding more sludge and foreign material to your engine because the detergent helps things pass through your filters. Also, what happens to the detergent once the gas is ignited in the engine? It may become concentrated or form some kind of byproduct that wouldn't be there if the gasoline was just pure.

Oh, and yes, there is NO reason to use a higher octane than recommended. Higher octance just means the gas won't ignite as easily under compression. For a base protege or 3, just use 87 octane. The MazdaSpeed engines probably have a higher compression requiring a higher octane so that the gas doesn't ignite before the spark plug fires.

meGrimlock

^^^ everything you wanted to know about gasoline in 3 paragraphs or less.

Roddimus Prime

I prefer getting my gas at the Mobil station near my old job. It's only pennies more expensive than "Jet Pep" which specializes in doo rags and menthol cigarettes and they have quick pass and fast pumps.

I buy diesel from truck stops like Petro and Flying J. It's always much cheaper but if I'm not on that side of town I go to my Wal-mart. FDastest pumps in town and only slightly more expensive than Flyin' J.

p.s. Put $7.50 in the scooter tonight....averaged out to 70.4mpg. Anyone else get better?

jsusanka

I always thought it was these.

http://www.toptiergas.com/

they are all by my house and so I usually get one of those listed on that site.

m9431

1) Use the octane recommended by the manufacturer. My Mazda 3 is quite happy using 87 octane, as was my Honda Accord. My Toyotas run better (have more power) and get better MPG using plus or premium. The use of a knock sensor advances ignition timing to make better use of higher octane fuels. If you use a higher octane than recommended, you're just wasting $.

2) Three of my co-workers have new Mazda3's like mine. They noticed that ethanol-free gasoline yields about 5% better MPG. I haven't tried this yet because I haven't found a conveniently located gas station that has ethanol-free gasoline. From what I have researched, ethanol-free gas is likely better because ethanol contains slightly less energy per unit volume than gasoline. I understand that ethanol is more absorbant of water and is more corrosive--not good. Frankly, I think that adding ethanol to our fuels was a dumb idea! Not only for the reasons above, but it has driven up the cost of corn and therefore our food prices.

3) I've been advised that much of our gasoline is sourced from the same large storage tanks before it gets to a gas station. Is there that much of a difference between brands? I don't know. But I have noticed that it seems that I sometimes get better MPG after filling up at certain gas stations.

My '3' 5-speed is has only 1k miles and MPG has ranged from 32 to 35 MPG. I think that it will increase somewhat. (But I'm spoiled by my VW' TDI's 50 MPG.) Still, my 3's MPG is really good, and the '3' is much more fun to drive than a Civic or Corolla! It reminds me of a VW. As I drive at least 500 miles per week and am kind of a fanatical engineer, I notice this kind of stuff.