Ok, I use the regular gas at the station. The one with like 15% ethonal added.

I think it is like 87 octane.

Does putting premium fuel like 91 octane in help/hurt the engine, or add horses?

What about those octane boosters? Good/bad?

 

(I'm assuming you don't have an L67)

If your car doesn't specifically recommend or require premium- and you don't have very high mileage- then putting 91 octane in is a waste of money.

Why would you need to boost your octane over what is available at the pump? Your engine is designed to run on 87, putting 91 in is a waste, so putting in octane boosters to raise it even more is more of a waste.

 

so what does octane really do then?

 

there are different grades that different vehicles run opitmally on like some supercharged cars can run on mid grad but run the best on high grade and turbo cars that run only high grade also same way with some high performance cars are made for high grade and some cars are designed to run on mid grade. it all depends on what has been designed for that vehicle to run on wich grade for wich car can run optimully to run on.

 

i ran 89 cause it made me feel better for the last year, then switched to 87. i get more gas for the same price now. thats the only difference.


i believe it has somthing to do with temperature of the burn.

 

http://en.wikipedia.org/wiki/Octane_rating

The ratings you see are also known as the AKI- anti-knock index. It is simply a measure of how easy it is to ignite. A lower AKI (number on the pump) means it will detonate easier. On high compression, or boosted engines (talking spark ignition engines here, not diesels)- it is possible for the air/fuel mix to ignite before the spark ignites it (due to all the heat created).

The problem with this is, the spark plug starts the burn from one spot, and makes a nice smooth flame wave away from it. With detonation- many things can start it- and you can have multiple waves starting at once- so it is possible that a detonating (or knocking) engine can produce higher than normal pressure due to having more area burning at once- but produce less power due to the multiple wave collisions before hitting the piston.

Normal engines are made to run on 87, so think about that for a second- if you car is made to run on 87, and runs knock free on it- what happens if you put a higher grade of gas in? Nothing- the spark still ignites it like normal. Higher octane gas doesn't make more power- or any other BS- it is simply more resistant to knock.

Good call! 87 is definitely the better bet.

 

ah! sweet, thanks for the info... I go around the automotive sections of walmart and those octane booster things make ridiculous claims like " we have jet fuel in our" and "add tons on HP!"