Contour Enthusiasts Group Archives Forums Modifications Duratec Performance Gas Question

After cleaning my EGR Valve Saturday, I finally found time to go fill up the tank. Goods news is no engine light, but thats not the point of my message. Since gas where I live dropped around 8 cents, I put the 93 octane or "super" in my tank this time. Did seem to notice a small difference in the motor. It sounds like it is running smoother. So I was wondering, what does everyone else put in their tank? cause the book says to use 89 octane or the medium grade.

I would think that if you dont have a CR of 10:1 or higher or FI you really dont need it. 87 would be sufficiant.
-tropictour

you really need to watch out when a general compression ratio is placed for fuel octane recomendations. there is really no way that you could run 87 in a car from the 60s with 10-1 and not get a knock factory. for most newer cars even ones like the csvt that have high compression ratios you can run 87...but, it is definitly not recomended. the computer can adjust enough in most cases things such as timing to deal with the fuel. however the car will then be WAY down on power and will not run right. bc of the things adjusted by the computer doing this can actually increase chances of overheating and not all knocking can be corrected. so in other words if you want your car to last stick with the manufacturers rating.

To answer the question of what do i use, Shell VPower and only shell vpower. It's the only gas that keeps my CEL from coming on. Then again, I'm quite sure one of my pre cats is going and this seems to be just a band-aid.

I'm using the VPower in my car and its gained a little pep since then. I'm guessing it cleaned out some of the gunk for me. The car was a little doggy feeling compared to the 95 Escort GT I had before it but feels about the same now.

I put in 93 everytime, unless they have higher(not to often)..... whats a couple of cents per gallon, It's just gonna end up in the ashtray anyway.

I've run 93 octane since i bought my car back in 02'. If you like how the 93 octane makes the car run your should try a couple of gallons of 100 octane sure its $3.00 a gallon but i'm paying $2.10-2.25 a gallon for the 93. sucks that 104 octane is $6.00 a gallon at the track .

I'll tell you this it will make a big improvement over 4K rpms but it sure does burn a hole hell of a lot quicker.

From what I remember, higher octane fuel has more of a controlled burn, where low octane is more akin to an explosion, with no real control of the flamefront or anything.