2017 Chevy Cruze diesel

gopher

Well-known member
Joined
Dec 10, 2005
I was puzzled by the official EPA fuel economy ratings for the 2017 Chevy Cruze diesel sedan as being 52mpg highway for the 6 speed manual transmission and only 47mpg for the 9 speed automatic (52/37/30 and 47/37/31 for the highway/combined/city fuel economy respectively). This is all the more surprising since the axle ratio for the manual is 3.65 and for the 9 speed automatic 3.17. Perhaps someone with greater understanding of automotive engineering can help explain this.
 

oilhammer

Certified Volkswagen Nut & Vendor
Joined
Dec 11, 2001
Location
outside St Louis (where it's safe)
TDI
There are just too many to list....
Parasitic loss on the automatic is greater, and also the gear ratio of the highest gear may not be the same, so the final drive ratio difference may not matter as much as you think.

Could also be that like many modern 11ty-speed automatics, they feel the need to downshift and upshift constantly on changing terrain, which reduces fuel mileage.
 

Jetta SS

Veteran Member
Joined
Oct 30, 2006
Location
Grand Bay, AL
TDI
'98 Jetta
That must be a typo. I keep seeing articles stating that todays automatics outperform manuals in every aspect, and the only reason for buying manual is driving experience. :)
 

oilhammer

Certified Volkswagen Nut & Vendor
Joined
Dec 11, 2001
Location
outside St Louis (where it's safe)
TDI
There are just too many to list....
Have to also remember the testing results are given after averaging, and something that controls something for you is going to produce more consistent results.

It is almost always going to be easier to boost fuel economy numbers with a manual gearbox if the driver really knows the tricks to properly operating one. Couple that with the fact that automatics, when they actually are an option, typically hover around $1000 more (with VAG cars it is usually about $1100). And as a general rule automatics require more PM costs and can often have expensive failure modes down the road.
 

turbobrick240

Top Post Dawg
Joined
Nov 18, 2014
Location
maine
TDI
2011 vw golf tdi(gone to greener pastures), 2001 ford f250 powerstroke
Interesting. I wonder if there is anything to it. Even if they did cheat in a similar fashion to VW, they didn't sell very many, and I don't see our courts coming down nearly as hard on an american automaker.
 
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