How accurate is the octane rating at the pump ?

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Just wondering if there is a city / state agency that ensures the accuracy of octane rating at gas stations ?

Couldn't some shady stations be selling 87 octane as premium 93 octane ?

How often would this agency test the pumps for octane, not the actual volume of gas pumped ?
 
The is agency responsible for units, weights and measures. Not sure if it is federal or a state agency. IIRC, in no octane is allowed + or - 2. Of course.this info may have changed.
 
I did notice at an out of the way station up in the Whites of NH that the pumps had the numbers "925" hastily slapped over where it had said "93" for the premium.
I would assume an inspector came by and forced them to stop advertising 93 based upon his testing?
I was impressed that the testing apparently was good to 0.5 octane...
 
Originally Posted by Mr Nice
Couldn't some shady stations be selling 87 octane as premium 93 octane ?

It's been reported on the BMW forums that some stations do this. Some BMW models are sensitive enough to where the computer records the octane of gas used.
 
Originally Posted by Virtus_Probi
I did notice at an out of the way station up in the Whites of NH that the pumps had the numbers "925" hastily slapped over where it had said "93" for the premium.
I would assume an inspector came by and forced them to stop advertising 93 based upon his testing?
I was impressed that the testing apparently was good to 0.5 octane...

I'll bet the station owner argued that 92.5 rounds up to 93. After all, the octane is posted at 93, not 93.0. We use the same argument at work when checking material to specification.
 
Originally Posted by Kestas
Originally Posted by Mr Nice
Couldn't some shady stations be selling 87 octane as premium 93 octane ?

It's been reported on the BMW forums that some stations do this. Some BMW models are sensitive enough to where the computer records the octane of gas used.

I wondered about this when my FXT started running poorly after a fillup on a very warm (for where I live) Saturday.
The FA20DIT has had some issues with surging in hot weather, but it was fine for the 2 hours or so I was driving around in the same weather before I got gas at a (very expensive!) Cumby station I almost never use.
My manual says that down to 87 can be used if necessary with the caveat that it probably won't run well below 91 octane. 93 is preferred per Subaru and a Subaru dealer told me that I had better not come to them complaining about how poorly my car was running if I didn't use SHELL 93!

Originally Posted by Kestas
Originally Posted by Virtus_Probi
I did notice at an out of the way station up in the Whites of NH that the pumps had the numbers "925" hastily slapped over where it had said "93" for the premium.
I would assume an inspector came by and forced them to stop advertising 93 based upon his testing?
I was impressed that the testing apparently was good to 0.5 octane...

I'll bet the station owner argued that 92.5 rounds up to 93. After all, the octane is posted at 93, not 93.0. We use the same argument at work when checking material to specification.

I am sure the owner must have been hot about that one!
I can't imagine why else the numbers would have been changed if an inspector hadn't forced it...I think this was when I still had a "RAV6" that ran fine on 87, so I didn't care.
 
I know , in our state , the accuracy ( in gallons ) of the dispensers are certified and supposedly checked . No idea about the octane or % of alcohol .
 
They check the pump calibration monthly here.i dont know if that includes an octain test or not. Ultimately the fuel in the tanks is the drivers responsibility. No company would allow their driver to put the wrong fuel in the wrong tank. I guess a station owner could bribe the driver?
 
Originally Posted by Chris142
Ultimately the fuel in the tanks is the drivers responsibility. No company would allow their driver to put the wrong fuel in the wrong tank. I guess a station owner could bribe the driver?

Isn't that the only factor ? How can a station owner manipulate this ?
 
Originally Posted by Kestas
By switching covers that are color coded?

So folks who pay for regular get premium and people who pay for premium get regular ?
 
Originally Posted by Kestas
By switching covers that are color coded?

I think most drivers would notice this. When I delivered powder cement I always went to the same places and I knew which colors went to what pipe for the different types I Unloaded.
 
Originally Posted by Virtus_Probi
I did notice at an out of the way station up in the Whites of NH that the pumps had the numbers "925" hastily slapped over where it had said "93" for the premium.
I would assume an inspector came by and forced them to stop advertising 93 based upon his testing?
I was impressed that the testing apparently was good to 0.5 octane...

It has been a while since I did octane testing in college and I no longer have access to ASTM standards, but the information I could find online says that the reproducibility of ASTM D2699 is 0.7. If that is correct then two different labs with two different operators cannot resolve the value to 0.5.
 
In Canada, the pump octane is stated as a minimum; so Canadian Weights and Measures will only require correction if the octane is found below the posted level.
 
Originally Posted by Kestas
Originally Posted by Virtus_Probi
I did notice at an out of the way station up in the Whites of NH that the pumps had the numbers "925" hastily slapped over where it had said "93" for the premium.
I would assume an inspector came by and forced them to stop advertising 93 based upon his testing?
I was impressed that the testing apparently was good to 0.5 octane...

I'll bet the station owner argued that 92.5 rounds up to 93. After all, the octane is posted at 93, not 93.0. We use the same argument at work when checking material to specification.


Yet prices are always posted as $x.xx9
 
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