I always use the highest octane possible. It's only a couple bucks more per tank, so why not?

 

i too have seen this debate over and over
#1 you are driving a 35-50 thousand dollar car (origionally) so why would u skimp on better gas for it?
#2 people complain premium is a waste and just hurts your pocket but you are driving a nice car and it costs me an extra $3 per tank or $6-$9 per month!!!! i spend more than that on one freaking drink at the clubs on the weekend! so why the hell would i even consider using less than recommended???
#3 93 octane issue--- in my state it goes 87, 89, 93 so you are already spending 10 cents extra for 2 more octane why not spent 20 cents extra for 6 more octane

if you want to use regular, go buy a kia or ford or chevy

ok im done now, sorry

 

I always assume everyone is chipped.......it makes more of a difference if you are chipped.

from "how stuff works"

The octane rating of gasoline tells you how much the fuel can be compressed before it spontaneously ignites. When gas ignites by compression rather than because of the spark from the spark plug, it causes knocking in the engine. Knocking can damage an engine, so it is not something you want to have happening. Lower-octane gas (like "regular" 87-octane gasoline) can handle the least amount of compression before igniting.

The compression ratio of your engine determines the octane rating of the gas you must use in the car. One way to increase the horsepower of an engine of a given displacement is to increase its compression ratio. So a "high-performance engine" has a higher compression ratio and requires higher-octane fuel. The advantage of a high compression ratio is that it gives your engine a higher horsepower rating for a given engine weight -- that is what makes the engine "high performance." The disadvantage is that the gasoline for your engine costs more.


So, I know this is an old debate.

I run 93 because I feel I get the best performance out of it....maybe its my chip.
If you run 91, and you dont ping, its probably OK. It is the reccomended MINIMUM rating.

So, run at least 91, 93 if you are chipped or BT'd.

 

87 octane!!!

It will not change your mileage!

All octanes are close in molecular energy during combustion.

The real catch is that 87 will detonate sooner than 88+ octane.

The other minor difference is that 87 will burn faster due to its lower detonation threashold during combustion when compared to higher octanes, assuming that no other variables exist.

The only differences in efficiencies that I can predict will be those related to spark timing because higher octane petroleum requires a slightly advanced spark timing to take advantage of its slightly slower reaction time due to its higher detonation temperature threashold.

The only time higher octane petroleum is worth its price is when you are already pushing the limits of the fuel itself. This only occurs at higher compression/boost where 87 will not suffice.

The biggest advantage of 87 is that you can delay your timing slightly to take advantage of its more rapid combustion rate. This way, less time is spent creating pressure during the upstroke. This aspect of 87 will be a good friend to your wallet when you consider that at cruising speed, a properly timed 87 engine will be more efficient than a 93.

My 1.8t is only pushing 150 hp, which is nowhere near the limits of 87. My other car, a 92 acura integra LS, is pushing 140 hp from the same displacement, but at a higher compression ratio. The integra only requires 87 according to the manual. Another, more potent vehicle, a pontiac vibe GT, requires mid-grade, yet has a comp ratio of 11.5 to 1! This is a higher head pressure than the stock 1.8t and the engine makes an additonal 30 hp over my A4.

The first person to cause me to speculate on this subect (other than my chemistry professor) was a local man who has been involved in automotive sales, repair, performance, and racing for 30+ years. I was very doubtful of his advice at first, but soon looked into and began to understand to greater extent.
His advice: put the cheap stuff in it.

For me, higher octane will come at higher boost.

 

yeah, well like I mentioned, if you are chipped or BT'd run the 93.

If your not chipped, and run less than 91, let us know if the few dollars a tankful covers your engine repairs in the long run.

 

yeah i didnt buy a $35k car to skimp out on $3 per tank... if you are that poor, go buy a kia rio and put 87 in it

i mean even if it doesnt hurt or help, your dinner for one night probably costs more if not 2x more than what it costs to use premium all month unless u do a ton of driving

 

Listen to the Germans who built your car. They knowz vwhat thierz talking about !!!!!! [sm=closed.gif]

 

i live in ma and most of the places sell 87,89,93...and the price dif. is almost always 10 cents between each. so from 89 to 93 its only 10 cents more a gallon...my beast has a 16.6 gallon tank so in a fill up its 1.66 cents more to use 93...so yea id say go with premium

 

If you need to use 87 thats fine, you won't destroy your engine (that's what the knock sensor is for!), however running premium will give a slight increase in performance due to the higher octane resisting pre ignition.