Okay guys, don't flame me too badly for this but I've been testing this and it seems to be true (at least in my case)...

Over the last few months I have tried gasoline from 4 different stations, and when I fill up at the Shell station (87 octane) I have a noticeable increase in power.... And I don't mean a little bit of a difference either, but very obvious. I wasn't sure at first, that's why I did the checking around with other stations.

Am I nuts, or has anybody else experienced this? Let me know if you have (or not)....

 

I haven't gotten around to gassing up the 7, but I will say in my little piece of crap Hyundai, it feels more responsive when I drop the pedal at the stop lights and stop signs.

 

Get your hands on some of Sunoco's or Citgo's 86. At least if you're naturally aspirated.

 

Hmmm, I'll have to check that out...

 

Different gas stations within the same brand vary also, some of the tanks they have leak, (think water in gas etc) others have screwy methods of measureing their octane. (yeah they are all supposed to use the same standard, but they don't.

kenn

 

Additives at the station in the tanks also very from station to station.

~T.J.

 

Some years ago one of the major mags, either Car&Driver or Road&Track, did some fairly extensive tesing and concluded that there is more variation from one batch of gas to the next batch at your favorite station than there is between brands. This is very difficult to evaluate on the road, and difficult enough in the laboratory.

But I don't need to speculate about this - I have my own expert. I have a relative who is a very smart chemical engineer, who has worked for years for one of the major oil companies, mentioned above, and has had the task of mixing gasoline. She says that they all use essentially the same processes and catalysts for cracking petroleum and refining gasoline. The different brands are so similar with modern cracking processes, that the energy produced is very consistent, i.e., fuel efficiency, performance, etc. The probability that you could change brands and immediately notice a difference is extremely unlikely.

There are differences, however. She says there are some "men in white lab coats working in a building back east somewhere, mixing the magic potion, which is a closely guarded secret." This is the stuff that is in the jug which the driver pours into his tank when he fills up at the refinery. If you believe the advertising, this is the stuff that improves combustion, prevents carbon deposits, keeps your injectors clean,and generally improves your life. (If you have heard Tom Waits advertising hymn called "Step Right Up", you have the idea.) These effects may be important over many thousands of miles, and are undoubtedly more effective for some engines than others. But if you perceive some short term effect you are probably halucinating.

And if you are doing comparisons with a rotary engine, you are definitely imagining any difference - these things will run on just about anything that burns. Well, OK, that is too extreme - don't run out an put Diesel in your tank.

 

Shell Gas = Shell salespeople. I agree, you are hallucinating.

Ray

 

i read somewhere that rotaries run better with the lower the octane rating. i dont know how, but that is something i came accross on the net a couple of weeks ago. is this true?

 

Do you guys have "Mr. Gas" stations in the states cause i own one here in North Bay, Ontario and i know we get our gas from Shell Ottawa (except for our ethanol, we get it from MacKewen) but people still go to the shell station after i show them the gasoline delivery sheets...those people are called label snobs

-Sam

 

"i read somewhere that rotaries run better with the lower the octane rating. i dont know how, but that is something i came accross on the net a couple of weeks ago. is this true?"

Yes, cheaper is better, disregard the label.

Ray

 

Yes. The lower the octane, the faster the burn process. Since the Rotary has such a long dynamic chamber (combustion chamber) it takes much longer for all the fuel in the chamber to burn. The faster the burn, the more fuel consumed, and the more power produced. Higher octanes may not burn completely before exiting the exhaust port, resulting in potential power loss and reduced economy.

 

When I fill my truck with shell gas from my local stations, I always feel the ignition retard from the knock sensor. Whatever it is locally causes some serious detonation in my chevy 4.3

 

i think what i saw may have been on the discovery channel, but im not sure. they were saying that the lower octane you could get for a roaty the better. they were saying like in the 70's for octane rating. i dont know anywhere to get that kind of gas though

 

Add a ton of premix. That lowers the octane rating.

 

I remember reading from an earlier thread on the same subject that back in the day the Mazda race teams used 67 octane fuel. I don't know if it was the way they rated it back then or if it really was such.

A quick search and a very extensive thread can be found somewhere. I'm looking for it again.

 

water runs best in my car

 

I heard the same thing. They also reportedly brought their own fuel to the track.
I bet that really chapped the competition, getting beat by cars running gas that was too crappy to even use in the tow vehicles. Talk about having an "unfair advantage".

 

Keep in mind that this is only true for NA motors, as the turbo motors will detonate with lower octane due to their higher compression ratios. Probably not as useful with some of the later higher compression NAs, either.

 

Correction: It was BP, not Shell.... I was very tired when I started this thread and got the name of the station wrong....

I really doubt that I'm hallucinating though......time to redline is definitely shorter with fuel from this station. I agree with just about everything that you guys are saying as far as brand names, and varying quality within those brands, but this particular station has something that my rotary likes......maybe they're substituting really cheap gas? lol.

Maybe another local rotar head can stop by and give it a try? It's the BP station at the West end of 28th street... Somebody back me up here!

 

Could this be due to ethanol added to the fuel? I was at an Arco the other day (BP affiliate, I think) and I noticed the 10% ethanol sticker on the pump that I don't recall seeing at other stations. I thought it was a winter additive in the first place.

I have no idea what effect ethanol has in gasoline other than a fuzzy idea that it improves emissions, so what I'm implying is that what Kentetsu's station has might differ from others he's used.

 

I fill up at a BP everyonce in awhile and i dont notice a huge increase, but if crappy fuel is better i can go to my local "2 Johns" and fill up there

 

I didn't notice any posting of ethanol content, and I usually check. I'll have to take a look when I gas up later today.