Synthetic oil + gas mileage

I have several questions regarding synthtic oil. Have others noticed a gas mileage increase with synthetic or synthetic blend oil?
I just switched to synthetic blend in my 1996 Integra LS about 6000 miles
ago. I noticed my highway mileage went up about 2 mpg, from 32 to 34 with the switch to synthetic. Is this similar to what others have seen?
I was having the oil changed at 3500 mile intervals, but went to 5000 with the synthetic. I have 80k miles, drive about 8000 miles a year, mostly highway. Is a 5000 mile interval reasonable, or could I stretch it to 7500? 7500 would end up making it an annual change. I live in central North Carolina, where it hits the 90's in summer and the 30's in winter.
Thanks.
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Not a whit in my case. And I keep extremely detailed fuel mileage records.
--
Tegger

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I suspect the lack of response is out of a desire not to get into another endless discussion about synthetic versus mineral oil. Those threads go on for weeks and don't resolve anything or influence anybody.
As far as your question, I participate in two Prius Hybrid fora and many of those guys are fanatics about fuel economy. Nobody sees any difference between synthetic and "dino" oil for economy but it's been brought up a lot. Most agree that overfilling the oil by half a quart, which is easy to do on the Prius, reduces fuel economy about 1%. (Fanatics, you know.)
Mike
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Not sure about the blends, but you should be able to go 10,000 miles on pure synthetic (especially with mostly highway miles) assuming it's not a turbo. (Don't get me started talking about my 1.8T Audi sludge)
Lots of info at http://members.rennlist.com/oil/Motor%20Oil%20101.htm but not much there about the blends.
--Art
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