[Nerys]

yeah uhh E35 can DESTROY your car. I mean really destroy it as in its totalled engine rebuild. Ouch.

also voids warranties as well

I don't have a low fuel light on the metro but I fill by "miles driven" in the van I fill at 300-350 miles. in the metro I fill once I have passed 400 miles

the problem with filling too soon is accuracy. you NEVER EVER fill the same way twice. unless you fill with the car parked the same way and until you see GAS in the opening of your fill hole and it stops going down IE filled to the tippy top. you NEVER fill the same way.

now the more gas you have to add the more this "discrepancy" gets watered down no pun intended :-) Especially if you have a smaller tank like a 10 gallon tank.\

if I missfill by even half a gallon that could equate to huge MPG readings when I do the math. Example lets say My car at "normal" fill needs 8.5 gallons and I went 460 miles

54.11 mpg

if I UNDER fill by half a gallon I will record 57.5mpg if i over fill by half a gallon i will record 51.11 mpg

thats a pretty huge "range" covering almost 7mpg almost a 6% discrepancy. the get the same 6% mis calculation on a 1.6 gallon fill you only need to screw up by .09 gallons less than a tenth of a gallon.

so fill consistancy is critical and the more gas you add the more diluted that missfill is.

a misfill on a 1.6 gallon fillup is much larger by percentage than a missfill on an 18 gallon fillup.

thats why you want to wait as long as possible before filling. it also "smoothly" our your FE differences ie a more accurate average.

Whenever I see people recording insane mpg fills with 1 and 2 gallon fills I immediately dismiss those figures because there is simply no way they are accurate. If your not using at least 80% of the gas each fill your just not likely to get good accurate numbers.

also fuel dilution becomes an issue if your changing gas. fill at half way and your running 50% old gas 50% new gas. ie you can not easily compare them that way unless you run at least 3 tanks to dilute out the other places gas.