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fuel consumption

rezadu

Ready to race!
im trying figure out if anyone else noticed this. So I went on a small road trip. 400 miles round trip (all highway) to break in the car. For the 1st 200 miles the MFI told me I got about 30 mpg (got in alot of traffic). And for the 2nd 200 miles the MFI told me I got about 33 mpg. Went there and back on one tank, filled up right b4 I left and filled up again when I got back. Total trip was 389 miles and I filled up 14 gallons. So according to my calculations... thats 27.8 mpg. I was expecting somewhere in the 31-32 mpg since thats what the MFI said....WTF?
 

woofie2

Ready to race!
im trying figure out if anyone else noticed this. So I went on a small road trip. 400 miles round trip (all highway) to break in the car. For the 1st 200 miles the MFI told me I got about 30 mpg (got in alot of traffic). And for the 2nd 200 miles the MFI told me I got about 33 mpg. Went there and back on one tank, filled up right b4 I left and filled up again when I got back. Total trip was 389 miles and I filled up 14 gallons. So according to my calculations... thats 27.8 mpg. I was expecting somewhere in the 31-32 mpg since thats what the MFI said....WTF?

was the car filled up at the same station?,
Same temperature?
using the same pump?
topped off completely full, no air space, because some pumps can foam or are extra sensitive to shutoff.
same alignment of the moon?

I see slight differences, 3-5% in the MFI and actual, but 10% as you saw is a little out of the normal.
 

Cackalacka

Ready to race!
thats 27.8 mpg. I was expecting somewhere in the 31-32 mpg since thats what the MFI said....WTF?

There has been quite a few discussions regarding the MFI. It has been my experience that the MFI averages out to be 1.5 mpg (~5%) optimistic.

I've been anally tracking my mpg since my car's initial break-in (~600 miles) for a year (~25k total miles) and for the past 6 months, I've been tracking the MFI assessment as well. I'll have to compile/graph my observations in the coming weeks.
 

tzd

Ready to race!
I think that is about right. Based on 20,000 miles of driving experience, I find that my real-world MPG calculations are about 3 mpg less than what's showing on the MFI.
 

MBorVW

Go Kart Champion
I think that is about right. Based on 20,000 miles of driving experience, I find that my real-world MPG calculations are about 3 mpg less than what's showing on the MFI.

Wow that is disappointing...does that piss anyone else off? Why the need to lie about mpg? They could adjust the MFI programming to be realistic, if they wanted to.
 

Carbon Steel

Go Kart Champion
I think 27 - 28 is realistic, this is what my all around experience is. I'm pretty happy, nice ride, power etc.
 

rezadu

Ready to race!
i mean 28 mpg is still pretty good, but it kinda pisses me off when the MFI is saying im getting 32 but im really getting 28. everyone is putting in premium gas, right?
 

J-Cooz

Go Kart Champion
i mean 28 mpg is still pretty good, but it kinda pisses me off when the MFI is saying im getting 32 but im really getting 28. everyone is putting in premium gas, right?

Yes please use premium, its a GTI. How many miles are on your car? Since its a 2012 I assume its pretty low. It takes a few thousand miles for the car to break in and get better mileage.
 

kristian19

Ready to race!
I'm averaging 7.5 -8 liters/100km in my car and I consider that pretty good for this car. I usually get 500-560km per tank on 91 and when I run 94 I get around 480 so it could be on how you drive it and such. Your next fill up drive like a baby and if your on the highway keep it around 100-115km (what ever that is in mph) and you should notice a difference.


Sent from my iPhone using Tapatalk
 

EvlSascha

Passed Driver's Ed
Fuel consumption depends on a lot of varying scenarios - how fast you drive, freeway, city, traffic, flooring it, easing into it, AC, no AC, etc.

The MFI, as a ton of others have said, is roughly around 2-3 mpgs off.

I've had my car for a month and average around 31-32 highway driving only. My commute is 50 miles of straight freeway with some traffic for about 20 of those miles to and from. I rarely use my AC. I'm also averaging between 70-80 mph. I also get better mileage in the morning when it's colder. The average has been calculated by me personally, not the MFI.

City sucks my gas which is why I'm usually spending about $80-$100 a week. I'm okay with that considering it's slightly more than what I was getting in my '08 Jetta. I don't baby her, but I don't drive her like a douche either. ;)
 

tzd

Ready to race!
I think (and this is just my own hunch, don't have any proof) how the MFI works is by taking periodic samples of fuel consumption, say every 10 seconds or so. You will see it if you switch to the instantaneous MPG screen instead of trip MPG screen. Notice how the numbers update every X seconds, and also if you lift off the throttle, the MPG will show as 99.9. So, for the trip MPG, it averages out these periodic samples and this causes the trip average to be higher than actual, because some of the data points are abnormally high when you coast at 0% throttle.
 

j4juke

Ready to race!
My mfi is consistently off by roughly 3 mph. I felt the same as op after doing my 1st actual calculation, but I'm used to it now and to b honest I'm happy with my mpgs. If u keep it under 70 on the freeway also, u will see a huge improvement in fuel consumption.
 

zanyrsc

Ready to race!
My mfi is consistently off by roughly 3 mph. I felt the same as op after doing my 1st actual calculation, but I'm used to it now and to b honest I'm happy with my mpgs. If u keep it under 70 on the freeway also, u will see a huge improvement in fuel consumption.
yes if you drive at 65 for a long trip you will see a huge jump on mpg.i get about 26-27. The best way it to get a phone app and use it every time you fill up. and yes use premium fuel
 

sethmark

Passed Driver's Ed
Take a GPS and figure out how far off your speedometer is. Then extrapolate.

Modern gauges are basically idiot lights. They don't show the actual data. Do you have ANY idea how many ridiculous posts would be here if the temp gauge was accurate?
 
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