mikeeeeey

Hello all,

Just picked up my '12 G Coupe yesterday and am thoroughly impressed so far. My only question is regarding the fuel type. My dealership told me you can use reg, mid grade, or premium...the only impact it will have is on performance. Can anyone be kind enough to verify this for me that I can use any kind without worrying about damaging the car?

Also, what does everyone consider a safe "break in" period? I have seen anywhere from 600-1,200 miles.

Apologies if these topics have been covered!

SwissCheeseHead

iTrader: (6)

Octane level should be 91 or higher. Don't substitute a lower octane fuel with an "octane booster." They're useless. Any less than 91 and the engine will start studdering, knocking and pinging (I know, my dealership left me with 87 when I drove off the lot). I'm sure it was the salesman that told you that. If you learn one thing from this forum, it's that salesmen are idiots.

Break-in period should be about 1000 miles. Don't hammer on it too hard....but then again you'll get varying degrees on opinion on this as well. Some people go easy the first 1000 miles, some people don't.

Welcome to the forums and enjoy the new ride! Don't let the mod bug bite!

KAHBOOM

iTrader: (4)

^ what Swiss cheese said...

nukee26

There's a reason the owners manual specifically calls out 91 octane or higher. I'll listen to the engineers that created this car before I listen to anybody from a dealership.

ayarj12

iTrader: (2)

Welcome! Another thing you'll learn around these forums: dealerships will say anything to make you happy and to buy more stuff from them.

But Swiss Cheese basically got it!

MPax

The car has a compression ratio of 11:1. This basically means that any lower grade of fuel than 91 will fire off of compression alone and the engine management system won't be able to compensate or control firing time.

chicago_animal

iTrader: (1)

I have yet to put anything below Premium in mine since I got it in April.

One question I do have about gasoline is where you buy it from. Do you guys only go to the Brand Name places like Mobile, Shell, Citgo...?
Also, Shell boasts about their nitrogen gas. Does that really make a difference?

seymore4

iTrader: (7)

It actually can, but goes into a sort of limp mode running on a "high detonation
timing map, dumps in more fuel, and basically just runs horribly. So... it can't compensate in a way that makes efficient use of the fuel since it is a factory high compression engine, but it won't blow up your motor either.

I would not recommend it running less than 91 unless its an emergency, any money you think you're saving will be more than made up for with chitty gas mileage lol

Running lower than the specified octane is also bad on the spark plugs and will cause them to wear faster

XSivG

Mikeeeeey,
just follow the fuel and break-in recommendations that are written in your owners manual and you won't go wrong !!! Afterall who are you going to listen to, the engineers that designed our car or the differing opinions of others ???
Good Luck with the new ride.
Russ

SwissCheeseHead

iTrader: (6)

Lately, I've been a gas snob since I started reading about top tier gasoline. I've been using exclusively Shell for the last 1000 miles since they're one of the few left remaining that sell 100% gasoline (no ethanol) in my area and will probably continue for the rest of the car's life.

I've read that Citgo has crappy gas :/

XCoop

Always use what the manual says for normal driving. There is only a few exceptions. You should run premium, or mid grade in a regular unleaded vehicle if your experiencing pinging when driven long on very hot days. When you are in high altitude areas, you will notice all the octane drops by two points. Around here, octane levels are 85, 87 & 91. Continue to run with the premium, but it will be a lower octane. I'm sure there's a lot more forum members who have ran race gas than have ran unleaded.

It is true that in some vehicles, you can get away with running a lower octane, but this is not one of them. No reason to own a car like this and cheap out on fuel.

chuckie311

iTrader: (3)

break it period is drive it like you would any other day!! these engines are built no need to baby it

TwoThree

iTrader: (4)

I use 93 in my car, but all of our loaners get the 87 treatment and honestly, I don't hear any pinging or knocking and it seems to run fine. Wouldn't put it in my personal car though. It's really not that much more expensive. You just bought a new car, treat her with the finer things.

KAHBOOM

iTrader: (4)

Yeah even if to fill up from completely empty, you are not saving a significant amount of money. The difference might be 10 cents per gallon from mid to premium. That would be $2.00 a fill up. If that's going to break you, then in my opinion you are in too much of a financial crisis to be driving a $40k vehicle.

SwissCheeseHead

iTrader: (6)

I left the lot with a rough idle because the dealer filled it up for me and I figure it was the gas. I filled up with 93 and it ran smoothly. I wouldn't ever skimp on gasoline. It can do a lot of damage.