Why isn't the fuel economy better?

[Tcoat]

Originally Posted by mazeroni

I am also super impressed with the AC so long as you are moving. I find that when at a stop the air blowing out the vents gets a good deal warmer (talking 100 F ambient temps). I am sure there is a good explanation. Also the super small interior makes it easy to modulate. My GTI was a bit of a pain. Go around a corner and the air in the hatch would move to the front.

Though my fuel economy tanks when running the AC. I don't know whether i trust the instant MPG gauge, but the different between AC on and off is at least 6 mpg. I have no statistical evidence, but I feel like I started to use at least 25% less fuel when the temps dropped to 70 around here and I keep the windows down.

My ac goes on in March and off in October since I do not like heat. I have seen zero impact on my mileage from the ac on either the average gauge nor my calculated number. Not one single mpg difference when running it and certainly no 25% drop. Dadhawk's very extensive data also shows only a 1 mpg difference between winter and summer and I would have to believe he uses his ac loads since he is in Georgia. The instant gauge is useless for any practical purpose and I don't even know why they have it. It always just seems to mess with people's head. Other than a very brief moment of playing catchup when the compressor kicks in the engine is not demanding more revs or fuel when the ac is running. These aren't the old school systems that had parasitic draw all the time and the compressor clutch kicks in and frequently to prevent excessive fuel use. Can probably find some numbers someplace and bet you would be surprised at how little fuel a modern ac system uses compared to those right up into the 90s.

[brz11b]

I have full exhaust and u uel headers and I'm averaging like 20 something combined. i love the mpg. boxer motors have never been know for gas mileage

[Dadhawk]

Originally Posted by why?

that's about what mine looks like too. Interesting. I wonder how much lighter I'd have to go to see it move upwards. Probably not worth the money. I'll probably do it anyways at some point.

Well, I can tell you that since owning the car it has gained about 40 lbs...on me (long story, but working to get it back off).

[Dadhawk]

Originally Posted by Tcoat

...If Hawk keeps the data rolling and doesn't change driving habits we may actually start to see the decline in a couple of years or so. I have seen loads of break in and wear out data on car components before (most artificially induced on test rigs) but this is the first time I have seen reliable data and results on a whole car.

Well, the plan right now is to keep the car until at least 200,000 miles and my current job location probably won't change unless someone just throws money at me, so you may get just that.

As noted in my Owner's Journal first post, I did change jobs about a little over 3 years ago, but the driving pattern really didn't change that much. It was almost the exact same distance (within a 0.10 of a mile) but a little less stop and go.

The tires also changed at 60,000 miles to all season tires from the Primacies to Bridgestone Ecopia EP422 Plus.

Other than that, it's been standard maintenance.

[Dadhawk]

Originally Posted by Tcoat

Dadhawk's very extensive data also shows only a 1 mpg difference between winter and summer and I would have to believe he uses his ac loads since he is in Georgia. .

The A/C pretty much runs all the time from late May to the end of September. In the Spring and Fall it runs about 50% of the time on the afternoon commute, with nothing on the morning commute.

Winter it also runs when you use the defroster I believe.

[Tcoat]

Originally Posted by Impureclient

The problem is the peak on the "peak and decline" theory on my graph will be somewhere in 20 years if I keep only putting 4k miles a year on it.

Who knows you could peak before a car that is driven more. Sitting can b just about as bad as driving in many ways.

I do almost your annual on a monthly basis so will probably be headed in the down direction before too long.

[Tcoat]

Originally Posted by Dadhawk

The A/C pretty much runs all the time from late May to the end of September. In the Spring and Fall it runs about 50% of the time on the afternoon commute, with nothing on the morning commute.

Winter it also runs when you use the defroster I believe.

Yes it does. As soon as you put it on the defroste setting no matter if set to hot or cold the compressor comes on. I actually really like that feature because it blows dry air even if hot. Nothing quite like blowing warm humid air against a minus twenty degree windshield to make things get interesting fast.

[Ultramaroon]

Originally Posted by Tcoat

Yes it does. As soon as you put it on the defroste setting no matter if set to hot or cold the compressor comes on. I actually really like that feature because it blows dry air even if hot. Nothing quite like blowing warm humid air against a minus twenty degree windshield to make things get interesting fast.

Physics is cool.

[Tcoat]

Originally Posted by Ultramaroon

Physics is cool.

[why?]

here's my fuelly, just for fun.

Originally Posted by Dadhawk

Well, I can tell you that since owning the car it has gained about 40 lbs...on me (long story, but working to get it back off).

Heh gaining weight stinks. I have to lose a ton. But supposedly every 100 lbs of weight change is good for 1/10 th an mpg.

[venturaII]

Originally Posted by humfrz

Were all your previous vehicles diesel powered ..... ??




humfrz

German.

[Quentin!]

Haven't managed to get above 27mpg. Varies between 24-27, about 85% city.

[Ultramaroon]

Originally Posted by Quentin!

Haven't managed to get above 27mpg. Varies between 24-27, about 85% city.

Oh, for sure. I commute in stop&go. That's my normal. Take a road trip. You'll be pleasantly surprised.

[Quentin]

Originally Posted by Quentin!

Haven't managed to get above 27mpg. Varies between 24-27, about 85% city.

I don't think I've managed below 27. LOL


Sent from my iPhone using Tapatalk