stuven

There aren't any BP stations in my area, so I don't know if the following brands are genuine BP, but "BP/Amoco Ultimate," "BP Regular," and "BP Silver" are all on the Top Tier list.

Tapiture

Oh somehow I missed that. Ignore the first part of my post then

rsilvers129

Carbon from using 87, or from not using TOP TIER™ 87?

cakasky

I never used 87 Octane. I dropped down to 89 Octane, BUT not from Top Tier locations.

My 2010 Q5 is an S-Line and I can feel it runs better at the higher 91 Octane level. Which is what I used early on for a few years.

amorak

Why buy an Audi and then cheap out on a few bucks of gas? Blows my mind.

auntrout

+1

Tapiture

It’s not a “few bucks” though, is it? Looked at the prices around here. At Exxon, regular costs 2.33 and premium costs 2.93. That’s 60 cents more a gallon. With the 20 gallon fuel tank on a Q5, that means you’re spending 12 dollars more, each time at the pump. I don’t know what kind of financial situation you’re in to call that a “few bucks,” haha.

markcincinnati

I just hit reply, so if someone else has already gone this route, that is why, I too, have.

Audi's ALL Audi's are designed for PREMIUM gas. Here in Ohio it is possible to find (typically) 91, 92 and 93 "octane" signs on our pumps. I'm talking about gasoline from BP, Mobil, Shell and -- my favorite -- Costco. The gasolines I have noted are all Top Tier. Please check the Top Tier website for an explanation of why you might want to consider Top Tier. http://www.toptiergas.com/licensedbrands/

Having said all of this, the engine management computer does have the ability to adjust the tolerance of the Audi engines to reduce or virtually eliminate pre-ignition (aka PING) if something less than Premium is used -- accidentally.

Repeatedly, if you're willing to ask dealer senior service personnel or hunt through long articles on the long-term effects of using regular in a car designed for premium, you will see and hear the term, "false economy."

What this essentially boils down to -- if you're really willing to wade through the reasons -- is that it is a "false economy" to use regular in an Audi engine. This actually translates to "it costs more to use regular than it does to use the proper fuel."

There are multiple reasons for this.

Here's the one that folks often relate to readily:

To protect itself from self-destruction (which is, after all, what would ultimately happen if the engine had a bad and long case of pre-ignition) the sparking instant is "retarded" which has the effect of minimizing (which is not the same as eliminating) the audible PING sound.

Reducing the sound does reduce the damage that is caused to the engine. If you lease the car and plan to get rid of it before 50K, you can (although I think this is unethical) use a lower grade of fuel and let the problem be the next guy's.

Meantime, while you're "cheating the system," so to speak, the retarded spark engine produces somewhat less power than the engine was designed to do and would, if it was burning pure premium.

Most folks are able to "sense" the reduction of power the retarded spark situation causes and almost unconsciously press the accelerator pedal a bit deeper. Fuel usage increases due to the driver's demands for "mo' power!" Of course, since the engine computer is only capable of partially offsetting the compression ratio of the engine (which is the prime reason the engine requires a higher octane fuel to begin with), the engine is slowly but surely destroying itself.

So, you use regular and you get:

More fuel usage
Lower power and as a bonus
An engine that is killing itself.

If you aren't bored yet, let me try again:

Audi's engines are optimized (some would say designed) for the type or grade of fuel that customers are likely to be able to obtain.

Audi engineers "optimize" engines for "best" efficiency and maximum power (for the factory state of tune -- here is not the place to go into "But what about tuners who can get 50% more power out of the engine?").

At factory tune, it is desirable to operate as efficiently and powerfully as has been engineered -- always.

Look at a "hypothetical" at a specific engine operating point, of 5500 RPM for example: If we're at that point and we're using premium fuel, we can "advance the spark." Within limits, the more the spark is advanced the more power is produced and with a lesser advance there is a loss of power. At some point, as the Moody Blues said, we find "The Balance." More won't give more and less will only take away -- power that is.

Audis are designed for premium and are set/adjusted/calibrated for a certain spark to obtain The Balance. If you put regular gas in the tank and do nothing else, what will happen?

PING! Give that man or woman a cigar!

Assuming the pinging is not so severe that it is likely to cause imminent engine failure, the Audi computer retards the spark event until the computer can't hear much pinging anymore.

Whew!

But when we retarded the spark, the engine ceases to be at "The Balance" (between power and self-destruction, among other things). Based on the specific design of the engine, the result is a loss of power, sometimes it can get to a 10% loss.

This just won't do.

So what do you do?

You press down harder on the accelerator pedal, thinking perhaps you can restore The Balance.

You can't -- at least until you put the right gas in the car.

Broken innards -- typically piston rings and potentially pistons themselves -- are the long-term result.

So the moral of the story: Using regular in an Audi engine will cost you more fuel, net you less power and depending on how long you keep the car will screw up your engine in a very serious way.

But, on that last point, probably not in the first 50,000 miles -- so if you don't mind lower power and spending more for gas and want to stick it to a subsequent owner, by all means, don't use Premium.

Drive it like you live.

markcincinnati

I had planned to say this, too -- buy a nearly $50K or nearly $70K Q5 or SQ5 and chintz out on the gas.

Pooof -- blows my mind too.

markcincinnati

See insert.