Hmm I'll try Chevron a try .. if its ever manageable for my pockets -_-;

I wouldn't want to put fuel on my future FRS. :)

I am a Chevron guy. How can you say no to cute little cars that talk.

I can't believe that nobody has done some kind of scientific test with actual specific results, it doesn't seem like it'd be that hard for some shop to do. I'm no car guy but isn't this something you could do on a dyno?

Gah old thread bump, sorry noticed too late.

its not a difference in HP as much as how rough your engine idles and accelerates ..

I've noticed Mobil being a bit rougher but more HP feel than Chevron but chevron feels smoother
I only fill Mobil/Chevron these days

Speaking of Chevron, I found the below at askville.amazon.com...

"I HAVE OWNED VIRTUALLY ALL BRANDS OF STATIONS AND HERE IS MY EXPERIENCE

First of all let me say that i am not a mechanic or car buff. I have however owned Chevron, Shell, Valero, Exxon and Independent (no name) gas stations and still own several. First of all let me say that someone made a comment about Shell or another owning the land so they control what can go into their tanks. That is absolutely false!! When a gas station owner signs a "fuel agreement" with a major company, you can only receive fuel from that company and not just anyone. If you did, that is illegal. You must and can only receive that fuel that you are contracted to receive. So that statement or comment is absolutely not true and not a factor.

Second, the only additive that has been SCIENTIFICALLY proven to reduce build up and lower emissions is TECHRON by chevron. I know the following is not scientific however i cant tell you how many hundreds of times i had people come in to my store (when i was a Chevron) and swear that their car got 5-10% and even higher gas mileage compared to Arco or unbranded (includes grocery stores, Costco, Walmart, etc) and much better performance as well. Generally speaking all generic gas is the same however i will tell you that in at least CA they are allowed to add "fillers" to their generic gas (basically adding impurities to decrease the percent of pure gas).

I (like an idiot) let my wife convince me that we get over a dollar per gallon off Safeway gas because we shop there for our grocery (i think they give like 30 or 50 cents of per gallon for every $100 one spends in the store). So we had a bunch of "gas credits" saved up and for like 3 or 4 tanks, we both put in only Safeway gas and here is our experience. My wife's car dropped from average gas mileage of 20 to high 16's and my brand new car (4 months old) dropped from average of 27 down to 22!! That is not an exaggeration it was actually a hair worse than that. When i took my car in to the dealer (who is very reputable in our city, they are number on in either CA or Northern CA) the service manger told me he had another customer a month earlier complaining of the same thing but also noticed a huge drop off in performance (thinking back i realized my did as well). The manger dipped the guys tank and stated that his Spectrometer (or whatever device he used to check purity of gas) showed that the gas was only 76% pure and had "fillers" of 24%. He then took the same device and dipped his tank (he only uses Chevron) because the client was skeptical and low and behold the device jumped up to 100%!!

That all i needed to hear. I told my wife that i don't care if Safeway is giving gas away (well maybe if its free :-) , I will only use Chevron in both of our cars period. Think about it, why would the major auto companies go thru the hassel and cost of shipping gas from over 500 miles away (from Michigan to Kentucky where many of the new car testing is done regarding EPA stuff and more) since the 1970's if there is no difference in gas. They have Shell, 76, Exxon, BP in Kentucky and yet they only use and want Chevron. They are the true experts and not I.
Another quick item to think about. Chevron is the same price as the other majors here and only Arco and Independents are about 5% cheapest at the most (usually only 2-3%) however if your mileage drops from 30 to say 27 that is a 10% drop in mileage so that is actually costing you more money to buy the cheaper gas and that does not even take into account all the other benefits of Techron on most likely reducing mechanical/maintenance costs down the road.
That is all i need to know. Anyway the choice is yours. Hope that helped someone.
sonny1130 22 months ago"

I've been putting Mobil, Or 76 or Shell

76 for me. Tempted to put racing fuel (100 octane) and mix it in to try it out :D

91 Shell for my Evo X. World of difference from Chevron.

e85, but when i have to 91(socal) at either Shell or Chevron

6 gal 91 from shell 4.2 gallons of 100 from Sunoco at a spot in orange or almost 8$ a gal.

I fuel at Chevron if given the choice. Their 91 seems to make my car proceed.

I've only used Shell thus far, running 91 of course.. but the other night (when taking some photos) I was outside the car as it idled and their they were.. the crickets... never noticed before as my muffler is gone so I don't ever hear em; obviously. So anyway I'm letting my tank drain then switching to Chevron.. really just want to experiment and see if anything changes. I don't mind the chirping because I've yet to hear it while I drive around.

I use nothing but Shell 91 (unless it's an emergency) and I've had no crickets ever (in about a year of ownership) across two FR-S. I really wonder if it's a localized thing.

Yeah that's the only thing I could imagine. .but then again I've noted others within similar surroundings without any reports. I don't know, I'll try the switch and see what happens if the results are the same then I guess it is what it is. ?