Octane VS fuel milage

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I have a question about upping the octane to boost fuel mileage. The car in question is my 99 Zx2 DOHC. The engine has somewhat higher compression ratio is why I'm asking like 10.8:1 is what I read. Would running 91 octane boost the fuel milage any? It doesn't ping, although the knock sensors might be retarding the timing with 87 octane.
Thanks,
Dusty
 
Give it a shot. Don't let the internet tell you how your aged car will or won't work. Too many variables.

Use the same brand and pump in similar weather conditions if possible, and run a couple tanks in case your spark tables take a while to relearn.

Static compression doesn't mean much in a world with EGR and fancy head design.
 
You usually don't get better mileage with upping the octane at the gas station. I have tried it many time with many brands...no luck. Use what your manual calls for is the best way, (sometimes I have used lower octane with no problems.
 
Originally Posted By: eljefino

Static compression doesn't mean much in a world with EGR and fancy head design.


This is true. And you could add cam overlap as some cars don't even need EGR!

I wouldn't hesitate to try a different fuel, as anything could happen. But you have to understand that premium is basically harder to burn.
 
Would depend on the ecu timing map. If the timing is aggressive enough with 91 octane you could see some benefit.
 
my eclipse has a *high compression* v6 that recommends "premium fuel only". ive taken much heat from members of another forum for running only 87 octane in it for well over 2 years without any problems, not really a loss in power, and the exact same mileage even though on paper, 93 octane should give it better mileage...but it doesnt.
 
Buddy had a 1998 ZX-2. Ran the cheapest gas he could buy in it, and flogged it hard...never gave him ANY problems over 130k miles. They are a tough, reliable engine!
 
Do you know anyone with a scanguage? If so, borrow and use it while driving a fair amount. The scanguage will tell you if the car is retarding the timing. If it is, then fillup with the next higher grade and check again.
 
Can't word it any better.

Many high-performance engines are designed to operate with a high maximum compression, and thus demand high-octane premium gasoline. A common misconception is that power output or fuel mileage can be improved by burning higher octane fuel than specified by the engine manufacturer. The power output of an engine depends in part on the energy density of its fuel, but similar fuels with different octane ratings have similar density. Because switching to a higher octane fuel does not add more hydrocarbon content or oxygen, the engine cannot produce more power.

http://en.wikipedia.org/wiki/Octane_rating
 
There was a year when a Honda suddenly had 20 more hp. All it took was a better knock sensor and feedback control to unlock.

Think of it like this, we have feedback fuel systems that are always keeping things perfect, why not run our engines at the bitter brink of detonation as well, with feedback and constant correction? It's being done, by Honda at least, and most likely by others. Knock sensors have come a long way since the 80s when they were only on turbo cars, and only as a last ditch motor-saving failsafe.
 
I tried octane 87 and 91 chevron on my 2006 camry v6. mpg is the same..

my camry v6 only need 87.

If I am driving lexus, I am not scare to put octane 87 ( top tier gas ) in this economy.
 
My Subaru H4 pulls timing on 87. Confirmed with scanguage and soon to be confirmed with ecu data logging. Probably unnoticeable to the majority of people, but the logs don't lie. So at the very least a higher octane will reduce the incidence of knock, which is always a good thing.
 
the only thing that concerns me when gas goes up like this is how fresh the premium fuel is? i mean i`m sure the premium sits a lot longer now due to people not wanting to pay the higher price. but i tried the 87 in mine,and it runs like [censored].
 
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Very unlikely that higher octane gasoline will save enough gas to pay for its extra cost.

Try checking your fuel cost as close as possible on repeatable drives. You want the miles per dollar, not just miles per gallon. You need to run more than one tankful for each trial, and make everything as repeatable as possible. Let us all know the results.
 
Originally Posted By: lexus114
the only thing that concerns me when gas goes up like this is how fresh the premium fuel is? i mean i`m sure the premium sits a lot longer now due to people not wanting to pay the higher price. but i tried the 87 in mine,and it runs like [censored].


There's a brand in Canada (Ultramar) that sells premium at discount every Thursday, and it's always lined up. That gives me piece of mind that it's fresh. Shop around, you may find something similar.
 
Car & Driver Mag. did a test several years ago on 4 different vehicles that were rated to run 87 octane. They found that any increase in mileage by using higher than recommended was buried within the variability of the type of test. Their answer was basically no improvement as best as I can remember. Ed
 
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