g8tor20

This is what I have been told before by some folks. What that is worth, who knows....

The premium requirement is mainly for the vehicle to meet the stated HP/MPG issued by the manufacturer. The advancement of ECUs has been amazing and can adjust to whatever you put in the car.

As for the no-name brand gas, I have always been of the impression that gas is gas. There are only so many refineries for gas. It's not like Pedro's gas station down the street has its own refineries. Most buy gas from the "big boys" who find and refine the stuff. Yes you don't get the additives but don't think that is a necessity in todays cars. Just my opinion.

We have an X5 with 160,000 miles and have been putting 87 since day 1. Still runs great. Had an Infinit G35 Coupe that had 70,000 miles and ran just like she did when I first got her. Also have a Lexus GS that is almost 6 years old and same story.

All in all, the luxury cars of today can adjust to what you feed them. I do see the value of putting in the high grade stuff but also see the other side of the coin that John stated.

With that said...driving 12,000 miles per year and averaging 22 mpg, that comes out to $164 bucks extra per year assuming an average of $.30 difference in price from reg to prem.

awryexperiment

I think you have received sound and reliable advice regarding Octane, so I will not beat a dead horse.

Regarding Top-teir: I never heard of top-teir until this post. After reading the website, I am not convinced that its necessary. The website is clearly a marketing tool... the underlying science and execution is varied by company.

I usually use a Fuel system/FI cleaner additive in my cars on a scheduled basis (about every 5000mi).

In my mind, I KNOW I get a dose of concentrated detergents in my tank and through my fuel lines and injectors. I know that it sits in the tank and lines and that I am doing it at what I believe to be a frequent-enough basis.

PEF

There was a 20/20 episode 15 or 20 years ago that looked into where gas comes from. They tracked travel gas trucks from gas stations to the refinery and back to gas stations, in Northern California. This covered all of the named stations as well as some of the no-name stations. They showed video of the same truck delivering the same gas to named and unnamed stations.

That video evidence with some light reasoning mentioned above (there are only a couple of refineries in Northern California) lead me to believe variance in gas "quality" is bunk. On top of that, conventional wisdom is that if your engine didn't ping you don't need higher octane fuel.

Even though my reasoning says I should buy lower octane gas, I consider the $164.00 a year (based on the math from g8tor20 above) to be a small insurance policy... so I buy premium.

HaveBullDogWillTravel

what can I say...
...couldn't find "TT gas" in my '76 edition of Encyclopedia Britannica

JFA in L.A.

That's because in 1976, the ad agency hadn't created the 'Top Tier' marketing concept yet.

I forget...was Top Tier before or after someone decided some guys would actually PAY to put nitrogen in their tires?

ELEVENS

The FSI Audis are incredibly sensitive to octane and to carbon buildup on the intake valves. On many FSI Audis, including my RS4, VAG-COM logs show timing is retarded 8-12 degrees under warm conditions even when using 93 octane (R+M/2). That's a big power drop. The timing retard is mostly restored after a manual carbon cleaning and gained 30HP. That type of performance increase is typical. So as your Audi rolls up the mileage, octane becomes even more important.

IMO Top Tier gas AND Nitrogen in the tires are worth paying extra for. I blend my own 95-octane fuel for the RS4 (using Top Tier Shell 93 base) and have an N2 cylinder in my garage for tires.

The G Man

Why would you buy a stable full of race horses and feed it junk food?

g8tor20

To say it simply, I don't race my thoroughbreds. I don't push my cars to their limits and don't need that extra little horsepower / torque.

I understand your reasoning and all. I knew I would get blasted on an enthusiast website, but that has been my experience with it...for better or for worse

loscoz

I've found that even stop & go in daily commuter traffic which is not testing the vehicles limits, is impacted with less performance (reaction) using the lower octane gas.

For those using the lower octane gas have you honestly tried 2 full tanks of this cheaper stuff, run to (about) complete E THEN tried 2 tanks of the higher (93) octane gas? Trying at your best to maintain the same driving style/pattern throughout?
For me it is DEFINITELY noticeable difference in Q's performance and worth knowing IF I need to go* the Q will respond!

*side note in Mass there are highway entrances with about a 20ft on-ramp from a dead stop (sign) ... if you don't have fast pickup you are run over!

g8tor20

I'm sure there is a difference. No argument on that one. I was just sharing that my experience with other new luxury cars and not having a single issue when using lower octane gas.

My Q doesn't arrive for another month and I will probably use 93 since this is a FI engine. Certainly use 93 if I go with the Stasis flash.

I actually used 93 on my G35 for a while (When the car was new and then for about 1 year when I had the supercharger on it as it was tuned for 93 so I had to do it). Went to a lower grade and felt absolutely no difference.

Again, I don't really push my cars so its impossible for me to feel the difference. I know there is a difference...just not one that is noticeable for me.

As for the Carbon Build-up....from what I have read, and I reserve the right to be wrong, no brand of gas or additive actually reach the intake section where the carbon build up happens....so it doesn't matter what you use.

My girlfriend has an 06 A4 (with direct injection) with 54,000 miles and she only uses brand name 93 gas and she has some big carbon build up. Car runs extremely rough and crappy in the low RPMs. No CEL stuff yet but I know its there. Gonna look into the BG clean.

And as for your on-ramps in MA....wtf. I drove up in the NE this summer...those stop signs / on ramps are horrible.