Quote:

...the amount could be almost a gallon.



Okay folks, some math to help alleviate the conjecture here and let you all know that you are in fact sweating some miniscule shite.

Let us assume a 1in. ID for fuel hose (pretty reasonable in my estimation). The volume of the fuel contained in the hose would be:

Volume= Area (ID) x Length = Pi*r^2 * L = Pi*(d/2)^2 * L
Plugging in some numbers:
V= 3.14 * (1/2)^2 * L = 3.14/4*L
V= 0.785in^2 * L in.

So this says for 1 foot of hose (12in.) there is 9.42in^3 of volume. 1 gallon is equivalent to 231in^3. So, 1 foot of hose holds 9.42/231gal or .04gal/ft. To get a gallon of gas in the hose you would need 24.5ft of hose. I would think that most gas pump hoses are on the order of about 8ft or so giving roughly 1/3 of a gallon. If I fill up at the pump and put about 3 gallons in the tank this amounts to 1/9th of the fuel added or about 11% of the fuel addition.

So how does this affect the octane rating of the gas? I would think we could do some weighted averaging to obtain the final fuel addition octane (assuming the last guy put in the cheap stuff): ((1/3)*87+(8/3)*92)/3)= 91.4 or ((1/3)*87+(8/3)*89)/3)= 88.8. So the rough percentage change for each octane rating would be a 0.65% reduction in the 92 octane rating and a 0.22% reduction in the 89 octane rating.

In other words – STOP SWEATING THE SMALL SHITE!

Here endeth the lesson.

Ride On! Airguy -------------------- You gotta' be smart to be lazy(and get a job done)