Congrats on the almost 700 mile tank.

 

On one hand, I think that the general admonitions here about the dangers of topping off are warranted. But on the other hand, I think that having someone like you try this and post about your experience could answer the whole 'what if?' question for other people and prevent them from trying it out themselves, which could in the long run mean less agregate risk-taking. So I guess I'm saying something that's a bit like 'good for you for doing something that's borderline-dangerous so that the rest of us don't have to!' which sounds weird and contradictory.

If you're going to try this kind of stuff, thanks for sharing your data!

 

Okay, I'll take the "hit" here! I've filled every one of my four tanks to the neck (fuel visible and to the top of the neck). I've now got over 2,000 miles with no trouble. The benefits of "neck-filling"?

1) Every tank over 600 miles with ease!
2) Guaranteed accurate MPG results

The negatives?

1) Possible contamination of the charcoal canister
2) Longer time to pump (lots of click offs!)
3) spilling an ounce or two if you're not careful

I'm guessing that the tank design keeps some air (fuel vapors, actually!) even with the fuel up to the neck. These systems (OBDII emissions from '96 and later vehicles) monitor the vapor pressure in the tank. If you leave your cap loose, you'll get a check engine light because the pressure sensor in the tank can't get a proper signal. If neck-filling the tank was a real problem, it would have triggered a check engine signal the very first time I did this. I'm not really worried! I'll be happy to give you periodic updates.

 

Man I want to take a long trip to find out what this car car really do mileagewise. I'm normally stuck in traffic on the 405 although they just opened the car pool lane near LAX. Should help with the MPG. I'm current working on my fourth tank.

 

From what I have read, you will get your best mileage on a road trip! I'm thinking of driving to San Francisco in the next few months. Maybe next month. I'll post my results (driving from Los Angeles).

 

I've always wanted to visit Yosemite.

 

Geremy that +700 mile tank is right around the corner...You can practically taste it.

For the past 3 weeks we here in the Atlanta area have been under afternoon wind storms and I've had a 10-25MPH sustained head/cross wind to deal with.
At night the wind is gone so no benefit at all.
Even with these winds, my past two tanks have been 840, and 841 miles each.

I have +200 miles on this current tank and haven't moved off of full.
It says 66 point something on the dash. But the tank is still young so who knows what the cards have in store down the road.

So keep up the good work and that good tank will be your next.

 

I actually think I must have been pretty close to 700 but I wimped out. I got 600 miles on my tank and I still had 1 tick left on the fuel gage. I wound up putting in just under 11 gallons. The prior fill up, I had topped it off into the neck - usually about 1.35 gallons past the first click.

Unfortunately, my round trip drive would have been about 160 miles to get back to my gas station so I knew I wouldn't be able to make it back - I work in NJ, which is where I fill up as it's about 5% cheaper than where I live in PA.

I may try it again, if I can get the mileage timed out right - 700 doesn't divide by 160 very well.....

 

Well another update... I'm at 450 (approx) miles on my 2nd try... and at 51.8mpg overall average. So I will easily hit 700 miles on this one, barring too many street drag races

For the record I always drive at or slightly above/below the speed limit and do not "pussyfoot" my acelleration.

Also, contrary to many people's reasons for buying a hybrid, I did NOT buy it for environmental reasons, I bought it because it will pay for itself within a couple years on gas mileage alone (versus a similarly equipped non-hybrid Civic). So, releasing a few VOCs or whatever during an "experiment" that I will only do once (once I've succeeded) is about 1,345th on my lists of worries.

 

Well I took my first road trip to Sea World yesterday. My average for the round trip was 54.4mpg(only 266 miles roundtrip). Man I am jealous of you guys that live on flat or very near flat states. The mountains kill me and I used the AC with 3 people on the first part of the trip driving about 70mph. Anyone have any experience with how much the AC effects results? Figured it was better than the windows down. second part of the trip I did concentrate on getting good MPG. Speed ranged from about 53-73mph depending on the road conditions. Up the mountains slow keeping to mpg down I took advantage getting the car up to speed.