gasoline in coupe csi

I don't have a fuelie (FI car), but when I have asked some gurus about which gas to use, they suggest Union 76's Premium over the rest.......

so, if there is a 76 around, I'll toss that in, if not, I make sure it Premium something.... :lol:

have I noticed any difference, not yet or not really, only have @ 5-600 miles on the new 3.3L...

HTH
-shanon
 
Does anyone use an octane booster? In my area, premium runs about 35 cents more than regular, for 4 more octane points. That's about $5-6 on a fill up. I've been looking into octane boosters to compare price/octane value. Has anyone done that type of analysis?

Any brands you like? The prices vary quite a bit. Can you get away with half a bottle per 16 gallon fill up?

(psycherunner, sorry to hijack your thread, but I thought it was relevent)
 
Given the higher compression ratio, I run premium. In my part of the world (the left coast) I use Chevron which contains Techron, an additive that cleans injectors, etc.
 
Actually they were designed for 99 octane (RON method) leaded fuel.... In the US that is about 94-95 octane ((R+M)/2 method). This is no longer available. However, I hear tail that you can mix higher octane aviation fuel in to boost octane. I also suspect that some of the stuff I drink in China would also serve well to boost fuel octane.

Also relevant:
- The higher the compression ratio the higher the octane needed; unless modified, older engines will lose some effective CR due to ring wear
- The more advanced the timing the higher the octane needed; retarded timing helps reduce ping but generally make performance more sluggish.
- The more "swirl" in the air/fuel mixture the lower the octane needed; our engines have lots of swirl (about 13-14x if I recall correctly)
 
Maybe someone can enlighten me on octane ratings and power output. If an engine will run without any pre-ignition (knock) on regular or mid grade gas, will using premium give more power or are you just wasting money?
 
Wasting money, aside from the increased detergents. Consider this: the Motronic 1.3 and older FI systems were designed around the user using a certain minimum grade. Therefore, it doesn't advance the timing any more than that minimum grade allows. If you use better gas, the car won't be able to adjust to take advantage of the additional spark advance the better fuel provides.

In comparison, newer cars use knock sensors. This allows the manuafacturer to set the "minimum" acceptable gas to premium, therefore getting all the power and mileage bonuses better fuel provides, but it stops knock if lower grade fuel is used by pulling the timing.

Even with a modern car, you won't notice a difference if you put in 100 octane over 93, because the computer won't know what to do with the extra "timing room" provided by the superior gas.

So, to make a short answer, using better gas than designed with these cars doesn't grant any bonus aside from the extra detergents. Heck, I use mid grade in my coupe for this reason.
 
I suggest you read the "Effects of octane rating" section of http://en.wikipedia.org/wiki/Octane_rating
It might seem odd that fuels with higher octane ratings explode less easily, yet are popularly thought of as more powerful. The misunderstanding is caused by confusing the ability of the fuel to resist compression detonation as opposed to the ability of the fuel to burn (combustion). However, premium grades of petrol often contain more energy per litre due to the composition of the fuel as well as increased octane.
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