wifey says fill it up with 87
01-18-2011, 02:37 PM
#31
Audi Forum - Posts like an A3
Join Date: Sep 2010
Location: Pemberton, BC
Posts: 84
Re: wifey says fill it up with 87
I agree with the "morality" question about not knowingly doing something that would /could damage a car because you plan to dump it. My interest was only in the technical part of the question about low vs high octane. Since I was one of two or three that suggested it would not do actual damage, I must be one of those Cheeba feels is both irresponsible and ignorant! :>)
My comments are not based just on feelings, but my own experience and quite a bit of reading/ research. I do not however, have much first hand experience with current Audi engines, so I'm interested in learning about them. I don't know if we have any Audi Tech's on the forum who can offer actual factual info?
My understanding is that the engine runs on the edge of knocking, kept in line by the knock sensor and ECU. It is constantly checking and adjusting timing as needed. This means, I believe, that it would advance until sensing knock and back off. Let's say you put in a tank of 87 and the ECU retards timing immediately. Then you switch back to 91. The ECU can only detect this by advancing back to knock and then adjusting, constantly running on the edge of knocking, allowing the engine to accommodate variations in fuel and optimizing efficiency.
My point is that running lower octane is no different than higher octane as far as being close to the point of knocking. But, if the knock sensor fails then it's possible that detonation damage could occur with lower octane. How much and what type would likely depend on the engine design, length of time , degree of detonation, etc.
Also, depending on engine design, shifting the timing away from optimum for long periods could possibly impact other components.
Any body able to add some factual info?
My comments are not based just on feelings, but my own experience and quite a bit of reading/ research. I do not however, have much first hand experience with current Audi engines, so I'm interested in learning about them. I don't know if we have any Audi Tech's on the forum who can offer actual factual info?
My understanding is that the engine runs on the edge of knocking, kept in line by the knock sensor and ECU. It is constantly checking and adjusting timing as needed. This means, I believe, that it would advance until sensing knock and back off. Let's say you put in a tank of 87 and the ECU retards timing immediately. Then you switch back to 91. The ECU can only detect this by advancing back to knock and then adjusting, constantly running on the edge of knocking, allowing the engine to accommodate variations in fuel and optimizing efficiency.
My point is that running lower octane is no different than higher octane as far as being close to the point of knocking. But, if the knock sensor fails then it's possible that detonation damage could occur with lower octane. How much and what type would likely depend on the engine design, length of time , degree of detonation, etc.
Also, depending on engine design, shifting the timing away from optimum for long periods could possibly impact other components.
Any body able to add some factual info?
01-18-2011, 06:07 PM
#36
Audi Forum - Posts like an A1
Thread Starter
Join Date: Jan 2011
Location: Toronto
Posts: 10
Re: wifey says fill it up with 87
Thanks for the replies. Though some unhelpful and many arrogant, there were at least 2 or 3 that offered actual insight pertaining to my question, which I am grateful for. At the posting of my thread, I was already committed to filling with 91, however my wife raised a point which I thought was reasonable as well. Affording the extra costs were not an issue. The issue was why pay more? As far as I can tell, there is no factual data of running on fuel, that is not at the recommended octane levels, severely harming the vehicle(s) in the short term or long. If anyone can direct me to real studies, I would love to read it.
An advantage of leasing a car is that you get a new car every few years and not have to worry about the one prior to that. A point pushed by many, if not all, sales/dealers I have encountered. I will carry that attitude with this new lease and the many more I sign after that. I could care less if a few moral police-keyboard warriors on here that say otherwise. Why should I care about the person who buys the car after this? That moral weight lies on the dealership, not me. I've paid for the right to treat the car however I like, as long as it is consistent with the policy stated from the company, the dealership and the signed lease agreement.
With that said, I will care for the car to the specified maintenance schedule outlined from the dealership.
An advantage of leasing a car is that you get a new car every few years and not have to worry about the one prior to that. A point pushed by many, if not all, sales/dealers I have encountered. I will carry that attitude with this new lease and the many more I sign after that. I could care less if a few moral police-keyboard warriors on here that say otherwise. Why should I care about the person who buys the car after this? That moral weight lies on the dealership, not me. I've paid for the right to treat the car however I like, as long as it is consistent with the policy stated from the company, the dealership and the signed lease agreement.
With that said, I will care for the car to the specified maintenance schedule outlined from the dealership.
Last edited by weilian; 01-18-2011 at 06:17 PM.
01-18-2011, 06:44 PM
#37
Audi Forum - Posts like an A3
Join Date: Dec 2008
Location: Canada
Posts: 94
Re: wifey says fill it up with 87
Sorry, I thought the original post was insincere and just to stir up the hornet's nest, which it did indeed. That being said, I have reservations about anyone's attitude who cares not about the person who gets the vehicle after they have intentionally not followed the manufacturer's guidelines. The moral weight lies not with the dealer, but with you, as it does with all of us.
01-18-2011, 06:54 PM
#38
Audi Forum - Posts like an A1
Thread Starter
Join Date: Jan 2011
Location: Toronto
Posts: 10
Re: wifey says fill it up with 87
Sorry, I thought the original post was insincere and just to stir up the hornet's nest, which it did indeed. That being said, I have reservations about anyone's attitude who cares not about the person who gets the vehicle after they have intentionally not followed the manufacturer's guidelines. The moral weight lies not with the dealer, but with you, as it does with all of us.
01-18-2011, 07:03 PM
#39
Audi Forum - Posts like an A4
Join Date: May 2009
Location: Canada
Posts: 193
Re: wifey says fill it up with 87
Okay, I have the manual in front of me...
The fuel recommended for your vehicle is unleaded premium grade gasoline with a minimum octane rating of 91.
Your vehicle may also be operated using unleaded regular gasoline with a minimum octane rating of 87. However, using 87 octane fuel will slightly reduce engine performance.
Use unleaded gasoline only.
So, the only restriction is to use unleaded gas.
Now, my car is an 2005 A4 B6, and the recommendations and restrictions may differ for more recent Audis. But if they are the same, well... the wife wins !!!
The fuel recommended for your vehicle is unleaded premium grade gasoline with a minimum octane rating of 91.
Your vehicle may also be operated using unleaded regular gasoline with a minimum octane rating of 87. However, using 87 octane fuel will slightly reduce engine performance.
Use unleaded gasoline only.
So, the only restriction is to use unleaded gas.
Now, my car is an 2005 A4 B6, and the recommendations and restrictions may differ for more recent Audis. But if they are the same, well... the wife wins !!!
Last edited by maxaudi; 01-18-2011 at 07:08 PM.
01-18-2011, 07:09 PM
#40
Audi Forum - Posts like an S6
Join Date: Apr 2008
Location: Oakville
Posts: 1,155
Re: wifey says fill it up with 87
The way I see it, you'll see a bit better performance and a bit better fuel economy from a 91 vs an 87
You'll probably also NOT have your car knock
You'll thus go quicker, go farther, and not break the car. All pretty good I'd say.
I'm tuned for 93, so I don't really think twice about getting 93 or better. I mean you (OP) are driving a $50,000 car, when all is said and done. If you're leasing it, you're paying about $700 a month for the privilege. If you drive 24,000km per year per your lease agreement, the extra 9% cost of 91 vs 87 is going to add about $300 a year to your total $8,400 leasing costs. I say why bother cutting corners? Just enjoy the car to its fullest.
You'll probably also NOT have your car knock
You'll thus go quicker, go farther, and not break the car. All pretty good I'd say.
I'm tuned for 93, so I don't really think twice about getting 93 or better. I mean you (OP) are driving a $50,000 car, when all is said and done. If you're leasing it, you're paying about $700 a month for the privilege. If you drive 24,000km per year per your lease agreement, the extra 9% cost of 91 vs 87 is going to add about $300 a year to your total $8,400 leasing costs. I say why bother cutting corners? Just enjoy the car to its fullest.
