My 2018 Q7 3.0 93 vs 87 octane test...
09-11-2017, 11:26 AM
#11
AudiWorld Member
Why would you "never use 87"? Are you suggesting that it somehow is damaging to the engine? That's just silly-talk.... Premium fuel is used to create more horsepower, and the car's ECU (at the manufacturer's choice) is optimized for 91. That doesn't mean 87 is detrimental to use, it just means that you won't achieve the advertised horsepower. Ahhhh...but how much less?!? That's the mythical question most manufacturers will never tell you. (You'll not Ford is the only manufacturer putting in print the difference on some EcoBoost motors, which is rather enlightening when you see the differences) Is it 5 hp less (because you sure will never notice that in the real-world driving) or is it 25 hp less? Since ever engine is tuned differently the difference between power and fuel economy when using 87 versus 91 is always different. However, as this poster is alluding to, in Q7 tune it appears fuel economy is not a beneficial part of the 91 octane tuning, power is the name of the game. Every car is different on how it reacts to different octanes, but don't fall prey to thinking you must use 91 in order to maintain your engine properly, because that's just a wise-tale.
My Q7 3.0 only has 675 miles on it. When I get about 1000 miles I will try 87 octane to see how mileage is. I also plan on towing with the Q7 but will use 93 octane when towing.
09-11-2017, 11:32 AM
#12
AudiWorld Member
One other thing I should add is using non-ethanol 89 octane fuel increases mileage by 3 - 4 mpg, which is significant. Non-ethanol is readily available here in SC coast because of the boaters.
09-11-2017, 11:54 AM
#13
AudiWorld Member
09-11-2017, 12:52 PM
#14
AudiWorld Senior Member
Thread Starter
09-11-2017, 01:06 PM
#15
AudiWorld Senior Member
Thread Starter
Did they really call it "performance pack?" As far as I know, they eliminated that option and every 2017 GTI, except for the base model and R, have a 220 HP engine standard.
09-11-2017, 01:39 PM
#16
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educate yourself on the subject and you might not laugh after all
I laugh when someone thinks that filling 87 will "damage the engine". Please.
Optimal performance with recommended octane rating, but 87 will run just fine for everyday use. It's a mental thing, just like how they sell that "in between" grade for those vehicles that require 87. Oh, let me go a step up to get slightly better quality.
This is why Costco only sells two grades of fuel.
I do not believe that just because invest a few more shiny pennies into a vehicle that you should not try to "save money". If you can save by pumping 87 at the tank, then good for you. I would do it, but my wife would not. There is no right or wrong answer. It's just a matter of preference.
Optimal performance with recommended octane rating, but 87 will run just fine for everyday use. It's a mental thing, just like how they sell that "in between" grade for those vehicles that require 87. Oh, let me go a step up to get slightly better quality.
This is why Costco only sells two grades of fuel.
I do not believe that just because invest a few more shiny pennies into a vehicle that you should not try to "save money". If you can save by pumping 87 at the tank, then good for you. I would do it, but my wife would not. There is no right or wrong answer. It's just a matter of preference.
Putting lower octane than recommended in your engine will result in premature ignition and knocking that will wear your engine faster.
Modern cars have a knock sensor and are able to decrease the compression ratio in order to prevent damage to the engine at the expense of power to some point however that does not mean that you should use it. If you want to use regular gas in order to save money should have gotten a natural aspirated engine with lower compression ratios.
https://en.wikipedia.org/wiki/Octane_rating
09-11-2017, 04:13 PM
#17
AudiWorld Senior Member
Thread Starter
The knock/ping sensors on cars are going off even at 91 octane, but at a higher engine load and higher intake manifold temps than when 87 is being used.
So for example, it may be with 91, the engine has to be at 85% load to have knock/ping, but with 87, it may happen at 70% load. Since it happens anyway with the recommend fuel, there is no damage.
https://community.cartalk.com/t/a-ne...-regular/88903
Last edited by rsilvers129; 09-11-2017 at 04:16 PM.
09-12-2017, 04:54 AM
#18
AudiWorld Member
If you open the fuel cap, I think it will say Premium recommended, 87 minimum. Can you double check the exact wording?
Did they really call it "performance pack?" As far as I know, they eliminated that option and every 2017 GTI, except for the base model and R, have a 220 HP engine standard.
Did they really call it "performance pack?" As far as I know, they eliminated that option and every 2017 GTI, except for the base model and R, have a 220 HP engine standard.
Last edited by jrtouareg; 09-12-2017 at 04:59 AM.
09-12-2017, 05:06 AM
#19
AudiWorld Member
09-12-2017, 05:19 AM
#20
AudiWorld Senior Member
Thread Starter
For a car that gets 20.00 mpg with 10% Ethanol gasoline, it would get 20.38 mpg with pure gasoline. So pure gasoline is a break even value around 5 cents per gallon more.