Octane Rating for 1M

[etr2016]

I live in AZ where generally speaking, 91 octane is the only gas available. I just read an article on a GTR forum that supposedly a gas station somewhat near me has 95 octane. Besides the cost of $6 a gallon, is there any negative impact of using an octane rating this high? Royal Purple sells an octane booster/stabilizer that is likely more cost effective, but I was just wondering in general.

[CarJunkie]

It won't hurt anything, but if the car isn't tuned for it, it also won't be any better than 91.

[nachob]

I would do some research before adding Octane Booster. There are several ways that you can increase octane and not all are good for fuel systems. You have to remember that these fuel systems are a bit on the delicate side with some having fuel pump failures and fuel injector issues. BMW has blamed US fuel quality for some of the pump issues and adding an aftermarket additive might not be good for them.

The car is direct injection which means it car control combustion temps quickly since the injector is in the combustion chamber. Just use high quality 91 octane and you should be fine.

If you want to add something to your tank, add BMW fuel system conditioner every 2-3 months depending how much you drive.

[etr2016]

That was my concern with adding anything to the tank - the fuel pump failures.

I do use Sea Foam for stabilizer when the car isn't driven for months at a time. I had a bad experience with letting gas sit for too long and Sea Foam was recommended by the dealer.

[nachob]

Originally Posted by etr2016

That was my concern with adding anything to the tank - the fuel pump failures.

I do use Sea Foam for stabilizer when the car isn't driven for months at a time. I had a bad experience with letting gas sit for too long and Sea Foam was recommended by the dealer.

Yeah thats probably fine since bad gas is definitely bad for the car but wouldn't add octane boost myself.

In the nineties I was a testing technician for Nissan"s IMSA GTP program. Part of my duties was the testing, cleaning and flow
Matching of fuel injectors for each motor. We used high octane race fuel that contained Toluene. That's the stuff in plastic model glue that melts the plastic.

We were finding that injector flows were dropping significantly in just one race. This lead to some engine failures. We tested Techron to clean the injectors and it worked. We were running straight Techron though. Anyway I don't recall if they ever found the reason for the clogging injectors. Then in LeMans both our cars lead the race for about 14 hours before disaster struck. The fuel cells on both cars which are bladders glued together disintegrated. Race fuel entered the cockpit and we DNF'd. Honestly it's been too long but we suspected something in the fuel attacked the adhesive in the fuel cells. We had run Sebring but that was only 12 hours and this happened after that. The point is that there are a lot of plastics, rubbers and polymers that can be impacted by substances in fuel, especially some additive that has not been tested long term in a car. And I say that because I know there is a guy out there that is going to say: I put acme power juice in my tank and nothing happened. Thats why I tell the story about how we ran 12 hrs at Sebring and win but fuel cells fell apart after 12 hours. Things can happen down the road after you introduce something toxic to the fuel system. I hope that helps! Techron good, other stuff not sure IMHO.