I get that the High Pressure Fuel Pump recircs and heats up the fluid. But damn, 1.5 gallons is a lot. Is there no other method? Basically we are dragging around 10+ pounds of unusable fuel.
Thanks, I'm still trying to figure out the MFD. Less accurate this time.
Yeah, I figured. Same here, hence my choice of a Golf TDI.
Volkswagen has been doing it in their diesel products for quite some time. If I remember correctly, it started with the Passat in 2012 as a response to the HPFP failure hysteria, in combination with what is an unspoken extended warranty on HPFPs and a slightly revised fuel system that uses different injectors and lower rail pressure. You'll notice that HPFPs have gotten a lot more reliable in recent years (Passats experience very few failures), so they're obviously doing something right. Roll with it.
Seems to make sense. I just wish the tank spec was reduced to reflect the recommended usage. I don't stress about it hitting zero or going a little under. 600 mile range is great. I won't be running it 100 miles past zero unless I have to.Volkswagen has been doing it in their diesel products for quite some time. If I remember correctly, it started with the Passat in 2012 as a response to the HPFP failure hysteria, in combination with what is an unspoken extended warranty on HPFPs and a slightly revised fuel system that uses different injectors and lower rail pressure. You'll notice that HPFPs have gotten a lot more reliable in recent years (Passats experience very few failures), so they're obviously doing something right. Roll with it.
It could even date back before that - I remember the Audi A8 TDI Top Gear episode where Jeremy Clarkson drove well past 0 miles until empty.
So, what we end up with is an obvious system design change. The engineers left that fuel there for a reason. You are welcome to second-guess them and take that risk for an extra 50 - 100 miles, but is it worth it? I mean really... squeezing that extra 10% of range out seems pretty unnecessary in the grand scheme of things. As for the 10 lbs of unusable fuel - it is being used... as a coolant and lubricant for a very expensive system.
I too have a bit of that lust. But for me, even averaging 43 by Fuelly is a massive step up from the 26-28 I had with my old Civic Si. I also see that you have the DSG, which, as psd1 notes, might hurt you *slightly* compared to some of the MTers here, maybe.
While I don't disagree that there is a difference, I don't think this is a fair comparison. Different car, different engine. My only point is that, so far, the only real evidence that the MT is significantly better than the DSG is anecdotal. Until I get a chance to comb back through the Fuelly data (potentially with more entries now), I won't be ready to say for sure. I think there is also a logical selection bias, as city drivers might be more willing to go with a DSG for convenience.
See, there's that "Slightly" word again. Since Badwolfs BEST tank in the Passat was 48 MPG, wouldn't it be fair to compare it to the BEST tank in the Golf, which was 56 MPG? I'm not great at math, but this appears to be +8 MPG...does that seem "slight" or "significant"? Best tank vs. best tank isn't anecdotal.
Fair, and good point about the AdBlue. I'd say the couple hundred pounds of weight differemce, engine improvements, plus any DSG->MT factor got you that nice win. You should lobby the EPA for a Better Than Highway rating system!
Best tank vs. Best tank with the same commute is a fine way to go about comparing the two cars, and it's a good idea to go back and look at the early days of the Passat. but I still think there are too many variables between the two cars to gain any real information on DSG vs MT. Aside from all that, the anecdotal aspect is that it's still a sample size of 1 of each car.
Are the transmissions (DSG/6MAN) in the 2015 Golf the same as the 2012+ Passats? If so, would it be safe to assume that there will be a similar difference in MPG between the Passat's and 2015 Golf's, all things being equal?
hopefully TDI-rex will comment on this in the not to distant future. That will give us a better idea of what the spread between DSG/6sd will be for highway when compared to the NMS Passat, which seems to be the most comparable model we have the significant data on.
That I don't know. Probably there are some algorithm tweaks at least. I'd say it's a fair first-order assumption that the DSG/Manual difference for the newer Passats is about that of the 2015 Golf DSG/Manual difference.Are the transmissions (DSG/6MAN) in the 2015 Golf the same as the 2012+ Passats? If so, would it be safe to assume that there will be a similar difference in MPG between the Passat's and 2015 Golf's, all things being equal?
I've been told that there is a slight difference in MPG between the Passat with the DSG and the 6 Manual...
Would you care to define slight, so when all the data is present we can know that you were correct.
Yes sir! This will be fun.
Agreed! As a recent diesel convert, I can testify that the FE is seductive. I'm really hoping the Golf holds up well, because if so, VW may have a long term convert.
Same here. I'm coming up on a month with the '15 DSG after owning an '06 RAV4 for over eight years. In the short time I've been driving the Golf, I've rediscovered how much fun driving can be, even here in congested central New Jersey. The fuel economy was a big selling point and, while I hope to see better numbers in the months to come, I'm already very happy to be getting roughly twice the fuel economy that I used to get in the RAV4. I'll add that I haven't really given much up in terms of practicality: the Golf has a lot of cargo space (something I was concerned with coming from an SUV), more than its small exterior appearance would suggest. I refer to it as the Tardis of cars, in fact. I genuinely hope this vehicle holds up in the long run and that I never think of buying something other than a VW in the future.
Welcome to the addiction! FE is almost a disease for me, and it has been for many years and many diesel powered vehicles. There are a lot of times when I cant wait to fill up to see just how good my numbers are.
While I think they are both made in the same factory (correct me if i'm wrong), I'm just not sure if their fuel regulations are the same as the US, and I'm sure there are other potential differences like that.
Managed to go through the current Fuelly data (well current as of yesterday night). I pulled only cars that are specifically labelled as DSG or Manual in some way. I included only cars in the US, and found 14 Manuals and only 4 DSGs still. I broke them up a couple different ways:
All US Cars, regardless of indicated Hwy/City %:
Manual: 44.0 MPG (4.3 stddev), 58% hwy
DSG: 40.9 MPG (5.3 stddev), 50% hwy
DSG 7% worse
Removing any with <50% Indicated Hwy/City %:
Manual: 44.9 MPG (4.2 stddev), 64% hwy
DSG: 43.8 MPG (1.7 stddev), 58% hwy
DSG 2.4% worse
So, if you believe people's indicated city/hwy splits (which I'm not sure I do), my hunch that DSG owners are doing more city driving may hold water.
Still a small sample on the DSG side. If only more Fuelly users specified! Of course, depending on which of the two ways you choose, the difference is less than my definition of "slight" from a few posts back (5%), and more than "slight" in the other case.
