whyman

I have the 2.0T, same engine as is in the A4 A5 Q5, Can i put 87 octane?

Eppieguy

Yes you "Can". You will lose some power but it will be fine.

M0J0

You won't lose any performance or fuel economy at all.

M0J0

My M3 had a 12:1 compression ratio and never knocked. The 3.0T has 10.3:1. Modern engines have variable timing etc that prevents knocking. High octane fuels do nothing for an engine anymore unless you are racing at a track.

jetsfan101

so it would appear only reason the germans recommend the 91 octane is to keep the power numbers as advertised.

Good example is the new mazda 2.5T engine. They say it's 250hp 310 ft lb torque @ 93 octane, but if you use 87, the hp will drop to 227, while maintaining same torque

Rals

I love the performance too much to drop the Octane. And not to be jerk, but isn't why we spent as much as we did getting this type of car? If gas prices are a sore point, then getting a CX-9, Pilot, Explorer, Highlander would have been the better option. Just sayin....

Eppieguy

^^^ This

jetsfan101

Why would someone spent the extra $10 per tank to get 93 when they are perfectly fine with the performance on 87/89. Like most people said you won't notice it. If they want to do it to save some dough, why not? They got an Audi because they like Audi, doesn't mean they should automatically throw money away on gas when they don't have to. @ 3 fill ups per month, its $360, and over $1000 over a 3 year ownership span. Just sayin....

Rals

Why bother having the manufacturer tell you what Octane to put in, if you're going to put something different in?

I don't recall Audi making the same statements as Mazda to say you can use lower octane. If they did.... fine I will concede. These companies spend million on R&D, why deviate from that? It's the same folks who go at lengths to use different weights of oil, rather than what the manufacturer suggested. End of the day that's your engine VS mine.

Grades of Gas & their Influence on Vehicle Performance | Speedy Apollo

Don’t Use a Lower Grade Then Outlined in the User Manual

You may be tempted to use lower octane levels to save money at the pump. However, using that lower rated fuel can actually cause your vehicle’s engine to run poorly and could damage it, as well as its emission control systems over time. If your vehicle is new, using that lower octane could also void your manufacturer warranty. You will also notice a decrease in gas mileage and engine power. To get the most out of your vehicle, fill up using the recommended type of gasoline. It is also recommended that you do research about a new vehicle before purchasing it to understand its requirements and the potential costs involved.

Rals

https://www.cars.com/articles/if-pre...1420684149253/