MPG boost after break-in

Just did my first fill-up 46.5 mpg. How much increase should I expect after the engine loosens up say after 10-15k miles?

scottydog said:

Just did my first fill-up 46.5 mpg. How much increase should I expect after the engine loosens up say after 10-15k miles?

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I have 44K miles worth of FE data, click my Fuelly lint to check yourself. YMMV

I have noticed a 7-10% increase from new to 30k miles.

Excellent fuel economy on these CR Passats, even when new. The post above about 60k miles is probably correct. I am at 51k miles on the Golf TDI and my fuel economy has consistently improved over the years/miles (proof in my signature on fuelly).

I have not found an answer yet as to why the Passat gets significantly better fuel economy than the Jetta, Golf or JSW with the same engine (and slightly different electronics).

secteur_cyclist said:

Excellent fuel economy on these CR Passats, even when new. The post above about 60k miles is probably correct. I am at 51k miles on the Golf TDI and my fuel economy has consistently improved over the years/miles (proof in my signature on fuelly).

I have not found an answer yet as to why the Passat gets significantly better fuel economy than the Jetta, Golf or JSW with the same engine (and slightly different electronics).

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I may be wrong but i would deduce that the passat does better because it already has the DEF spray that comes on all the MK7 jettas and golfs. the DEF allows to tune for an even leaner burn on the air to fuel ratio. the leaner you burn the more NOx you create, however the urea injection combats the NOx completely allow manufacturers to increase fuel economy via fuel mapping. thats why the new MK7s boast a 45mpg rating (@80MPH AC ON) mind you. the mk6 with dsg can barely hit 42 at that same rate. i really wish i couldve gotten a 6 speed manual.

secteur_cyclist said:

Excellent fuel economy on these CR Passats, even when new. The post above about 60k miles is probably correct. I am at 51k miles on the Golf TDI and my fuel economy has consistently improved over the years/miles (proof in my signature on fuelly).

I have not found an answer yet as to why the Passat gets significantly better fuel economy than the Jetta, Golf or JSW with the same engine (and slightly different electronics).

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This has been covered elsewhere. The difference is the AdBlue system (now that the smaller cars are getting AdBlue, they should come up in mileage, ceteris paribus). As I understand it, the short story is temperature. Higher temps = greater efficiency. But without Ad Blue, engine has to be run less hot to meet emissions. With AdBlue, the Passat (even with the same engine otherwise) is tuned to run hotter = greater fuel efficiency.