I have a friend who owns a Flying Spur. We were at the gas station the other day filling up and he chose regular gas!
I told him he was crazy, and he told me that I was crazy for putting premium in my car (2005 GT)
He said it was a complete waste of money and said he's always used regular gas in all of his cars including his M5, 550AMG and the Flying Spur.
I was shocked. It would never cross my mind to put in anything other than premium into a higher end car.
He can certainly afford it, so it's not about him being cheap. He just says it doesn't make a difference and choosing premium is just a waste of money.
He told me he's never had any issues using regular gas.
Anyone have any feedback about this?

 

Our cars can run on both, however it has to be noted the Ecu's constantly monitor engine knock using 4 knock sensors.
If you have a tune then it probably was designed for premium. However if you put the wrong fuel in and the engine knocks the ignition timing is retarded to stop knocking. This is a continuous process.
On a sandard engine tune this monitoring still takes place hence both types of fuel will be ok.
In very hot weather, the ecu might pull more timing on regular than on premium so you would notice some difference but nothing outstanding.

 

There's nothing really premium about "Premium" gas except that it has more anti-knock compounds which are typically needed to avoid knocking (which can damage pistons) in high compression engines. Today's computer controlled systems can adjust timing for differences in octane level but you may lose some performance and/or gas mileage. I only fill up once a month so I don't mind spending the few extra bucks. Buying fuel at Costco, the difference is minimal.

 

Running lower octane against knock sensors of a modern car won't harm anything. You just get less power and worse fuel economy. I've gathered quite a lot of statistics of my cars over the years (decades now) and taking the price difference in consideration, cost per mile is typically slightly lower when I use premium. In addition to that, It's sheer madness to buy a high performance car and handicap it by using low grade fuel.

 

Octanes should not be the issue, but new ingredients to the fuel may bring some problems...
Here in UE we have eco-terrorism and they put more and more bio-components to the fuel.
Recent regulations moved E5 towards E10 (5% vs 10% of bio-components).
According to specialists some older version of VW engines (tsi/tfsi) and Mitsubishi's GDI engines may be impacted,
but other engines should deal with E10 with no issue - this is the msg passed in the car-community.
But... for sure the cars which are used rarely, may have problems of that, cause the bio-component intensive fuel is more hygroscopic and it absorbs water over time.

 

The problem is, if you are using lower octane fuel, and then relying on the knock sensors to retard the timing to stop said knocking, aka pinging, then said pinging has to take place for the sensors to acknowledge the knock to do their job, therefore some knocking has to occur first, therefore possibly creating damage, if you have ever seen piston damage, or rod journal bearing damage from pinging, then you would understand, so, why take the chance for a few dollars at each fill-up, I mean seriously, why buy a high-end vehicle, to treat it like an economy vehicle.

Just my opinion, as I first hand saw what the lack of octane and to much timing did to my 13.5 to 1 compression engine back in the day, (I didn't know that I had 13.5 to 1, the machine shop milled both the deck and the heads too much) I never heard the ping until one day while taking off from the light, in the left lane next to the divider, I was like, "holy crap, what is that", I was running Amoco 93, Shell 93, or Sunoco 94, I switched up to Sunoco 104 and had no issue any longer, I even through some 110 in there, wow, what a difference in power and response, but, it was to late for the bottom end, the engine builder was shocked, but in turn, took responsibility for the 13.5 to 1, and the engine timing, as he is the one who set it all up to run, lesson learned on my part.

Johnny

 

These cars have various versions of Bosch ME7 ECU at least up to MY 2010. One of (many) robust, modern ECU:s that are very cautious to back off timing and boost at the first signs of impending detonation. I've ran some at way higher (close to double) specific outputs of these Bentleys at boost and timing fine tune self-learn with absolutely no issues so I wouldn't be too worried about any knock damage. These ECU:s are approved by beancounters throughout the car industry, with an eye on having ECU prevent any meaningful damage under warranty well before it happens.

You just lose a bunch of power, response and fuel economy by using sub-par octane fuel. On the other hand they also have tune-up capability, gauging the trim tunes on the fly and mine absolutely loves ARAL 102-octane pump gas whenever it's available.

 

In some areas of the uk, you cant get premium. Northern Ireland dosnt sell premium ( we call it Super over here 97 to 100 Octane). Even in Scotland way up in the Highlands some garages only sell regular( which is 95 Octane.
Recently the regular has had extra Methanol for environmental reasons. We call that Unleaded E10.
Its not quite as simple as using premium (Super) some times you have to use what you can get.
The Bentley Continental can handle either fuels with impunity.

 

Great replies from everyone, thank you all!