Re: Terrible mileage 99 GLE

David Geesaman wrote:
> Ralph Hertle wrote:
> 
>> Dave:
>>
>> David Geesaman wrote:
>> [...]
>>
>>> I've done two years of serious research tracking my fuel economy.  I 
>>> used only 93 octane for several years before switching to 89.  My 
>>> fuel economy did not change at all.
>>>
>>> I imagine under very heavy load there is a difference, but for 
>>> routine driving you will not see anything.
>>>
>>> Dave
> 
> 
>> A higher rated fuel than what the manual recommends has no effect on 
>> power or fuel economy. Nor does it have any additional quality. Higher 
>> rated fuels than necessary are simply money wasted.
>>
>> Ralph Hertle
> 
> 
> Yes Ralph, all that is true and well-known.  However, the Maxima's knock

> sensor will trip if you run lower octane fuel and adjust timing.  The 
> net result can be loss in both power and fuel economy.  My experience, 
> sup****ted by the data I've collected, is that stepping down from 93 to 
> 89 octane has not caused the computer to adjust and lose fuel economy.
> 
> Also, fuel economy wasn't the only thing I was interested in learning



> from tracking my mileage - I also know exactly what I'm spending on fuel

> per month and how many miles/day I drive.  Makes oil changes very easy 
> to keep track of.
> 
> Dave
Going down from 91 to 89 octane is a small step down, so any loss should 
be minimal, and, if you haven't noticed a power loss perhaps your 
driving habits are not so "enthusiastic" :)


I know that once I had 87 octane in my 98 Maxima and the moment I 
floored it, all computer hell broke loose. The car started pinging, then 
the computer adjusted and I felt a huge power loss. It didn't like 87 
octane at all.

Another factor we should keep in mind is where the Maxima is located. A 
maxima at 5000 feet above sea level does not need 91 octane, whereas the 
Maxima at sea level can take full advantage of the richer air and needs 
to richer fuel to maximize power and economy.



CD