Actually getting 400 miles each tank?

[i12drivemyMP5]

The rpm in sportauto is 3000 at 70mph....65 isn't much less, like 28-2900

 

[tweety2300]

65 is 3000 in a manual 75 is 3500

 

[sealuva]

Is the rev being at 3500 a cause for the decline in fuel economy?

 

[SoCalMP5]

Is the rev being at 3500 a cause for the decline in fuel economy?

It's both that and the added wind resistance. I wonder if the auto and manual sort of cancel each other out around 65mph...theoretically, autos have more parasitic losses at the driveline than manuals (and make less HP to the wheels), but it also is geared taller which means lower RPM @ freeway speed. So I'm thinking the economy of an auto vs a manual, both at 65mph, might be pretty close to each other.

 

[i12drivemyMP5]

Took the crossbars off the other day & put in the fill panels. Looks so weird like this to me. Wish I had the strips to eliminate the rails too. Did seem a bit less wind noiseish on the way in on the frwy this morning I guess. We'll see if I get the 2-3 mpg more out of the next tank. Bout time for an oil change too so both of those should have some noticeable effect...........

 

[JDM_Pro5]

65 is 3000 in a manual 75 is 3500

yeah I hate that, really wish we had a 6th gear. Only flaw in the P5 imo

 

[Hank3]

I got 415.6 miles from my last tank with all city driving. I did what some of the members suggested recently and filled up until I saw gas...to alleviate the differences from pump to pump as to when they cutoff. I got 29.8 MPGs and it took 13.96 gallons to fill up until I saw gas in the fill hole. Will see what I get from this tank, but it should be right around 30 MPG.

I've tracked 66 fill ups now on Fuelly and my overall average is 30.6.

 

[tweety2300]

So that's how you guys get that many miles to a tank. Keep in mind that much gas can keep the tank from ventilating properly

When I fill up its usually around 12 gallons from an 1/8 tank to full, but I have a big dent in my tank

 

[Hank3]

I've read/heard debates about filling gas to the brim. With knowing that you can't believe EVERYTHING you read on the forums/Internet, I'm going to be filling it to the brim just for a few times to get a good enough sample of what my MPGs are. My MPGs are off from tank to tank when I stop filling when the pump shuts off. I can't guarantee that I'll go to the same gas station and pump every single fill up so filling it to the brim is the best way to get some more accurate measurements.

 

[SoCalMP5]

I've read/heard debates about filling gas to the brim. With knowing that you can't believe EVERYTHING you read on the forums/Internet, I'm going to be filling it to the brim just for a few times to get a good enough sample of what my MPGs are. My MPGs are off from tank to tank when I stop filling when the pump shuts off. I can't guarantee that I'll go to the same gas station and pump every single fill up so filling it to the brim is the best way to get some more accurate measurements.

That's why it's an average...that way you don't have to differentiate. It already takes variations into account - that's what average means. It's not like it's going to be anywhere close to a full gallon difference. And across 66 tanks, let's say you realize the pump on tank #67 gave you 0.1 gallons (one tenth of a gallon) less than the last one. Fuelly doesn't carry out 4 decimal points, so you wouldn't even see it in your results unless it happened dozens and dozens (if not hundreds) of times! Fuelly rounds to the nearest 1/10 anyway. There's simply no way to track with any more accuracy than that. There are too many other variables.

For me, I fill until it stops, and then I grab the handle once more until it stops the second time. I also stop at the same 2-3 gas stations the vast majority of the time (so far, of my 6 fillups, they have been at the same 2 stations...one near work, one near home). I imagine most people do the same thing.

 

[i12drivemyMP5]

Every time I fillup (generally at same station) and the pump cuts off I always get most, all, or a bit more than another gallon in slowly filling to brim. How soon it cuts off is going to depend on pump delivery pressure with it all bubblin up in the neck it causes. Brim is a much better reference point to tighten up calculations on IMO. Using the brim should leave you with less variables, mostly the accuracy of the pump calibration & your trip/odo accuracy. All you have left is trip mileage divided by gallons of next fillup to brim. The other variable is how different I may have driven that tank compared to the last tank. That is what should be averaged - all frwy vs city or mix, did I drive nice or do an autocross, was weather and terrain generally the same as my usual commute.

 

[SoCalMP5]

Every time I fillup (generally at same station) and the pump cuts off I always get most, all, or a bit more than another gallon in slowly filling to brim. How soon it cuts off is going to depend on pump delivery pressure with it all bubblin up in the neck it causes. Brim is a much better reference point to tighten up calculations on IMO. Using the brim should leave you with less variables, mostly the accuracy of the pump calibration & your trip/odo accuracy. All you have left is trip mileage divided by gallons of next fillup to brim. The other variable is how different I may have driven that tank compared to the last tank. That is what should be averaged - all frwy vs city or mix, did I drive nice or do an autocross, was weather and terrain generally the same as my usual commute.

This explains why you shouldn't overfill your tank - in short, five percent of your gas tank's volume is reserved, and required, to allow for gasoline vapors to expand. So if you have a 25 gallon tank, the the most it will hold is 23.75 gallons. Overfilling the tank can cause vapor lock in the fuel line, damage to the fuel pump, your car's PCM to throw false trouble codes, federally required emissions tests to not be run, and in worst cases, the car to catch fire (due to excess vapors around the tank and/or raw gasoline dripping from the vapor vent).

Read more: http://wiki.answers.com/Q/Is_it_bad_to_overfill_your_gastank#ixzz1rxFHtc4t


http://www.aa1car.com/library/evap_system.htm

...just to get a couple extra ounces in? Or fool yourself into thinking you have the accuracy of a laboratory-controlled scientific test? No thanks.