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25%+ increase in milage <SNAP> - SUNOCO ULTRA 94

9491 Views 31 Replies 16 Participants Last post by  Insightful Trekker
This is my first post here. The reason is, I have had nothing to contribute since getting my brand new 2004 CVT several months ago and visiting this site prior to this. But the time has come!

The weather here in NJ has been in the mid to low 40's for some time now and continues in this range. My mileage has been 50 - 52 mpg during this time.

Last week it was time to fill the Insight up. Having read a number of posts here regarding premium fuel, both pro and con, I thought I would give it a shot. I filled it up with SUNOCO ULTRA 94 octane and reset my FCD. After about 75 miles of driving the MPG was stabilizing between 68 - 70 MPG! After another week of driving 300+ miles, the MPG remains the same, 68 - 70 MPG! No difference in temperature, no difference in driving habits or terrain, essentially no difference at all... except the fuel.

Now I understand that there are all sorts of varying opinions regarding this issue, many with what seems to be a good 'scientific' basis or reasoning as to why this mileage increase can not be attributed to the type of fuel. But facts are facts. And I must engage in a psychotic break with the interpretation of reality to deny that use of this particular fuel does not have a dramatic effect on the increased mileage of the vehicle.

I would suggest strongly the use of SUNOCO ULTRA 94 to increase the MPG, or at least try it. For those who may use this fuel and do not have such success, you too must face the reality of your experience, but I would suspect that it has something more to do with engine performance issues than the fuel. Keep in mind, my vehicle is brand new (7.5K miles to date).
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OK... lets be honest hear... if you use higher octane fuel. You are not getting better performance. There are two effect that the higher octane will have.
1) More advanced timing = more hp, better combustion
2) Prevents detonation at current timing (detonation is bad!)

Since there is no way a properly functioning insight engine is going to be having detonation issues at all, anywhere within its rev range. The higher octane is doing nothing but costing you an extra 20 cents per gallon.

For those guys who now have turbo insights, thats a different story. They will need higher octane, because bosting your engine effectively increases your compression ratio alot, and you may have issues with detonation!

Thats my $0.02
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