New to this site - if I'm doing anything wrong please give me a chance to correct myself before hitting me with close question etc!

I'm very interested in the efficiency of car engines, particularly in relation to year (focus on past two decades), manufacturer (focus on BMW but all would be much more useful), volume and cylinder count. Also interested in RPM and throttle position, but I think that's a separate question.

To clarify, I specify engine efficiency as the efficiency of conversion from fuel energy to kinetic energy. Wikipedia cites it as around 20-25% - I'm curious about how this number varies with the aforementioned variables. I'm not looking for MPG or L/100 km, as that's taking into account factors beyond the engine - car weight, aerodynamics, electronics etc.

So fields that I'd want to see:

  1. Model number
  2. Manufacturer
  3. First year in general production
  4. Displacement
  5. Cylinders
  6. Fuel type (or petrol cars only)
  7. % Efficiency
  8. Maximum power output (not a must but would be helpful)

Is there any open data relating to this? I hope that by "Open" I mean "can be used for any purpose including commercial".

  • 1
    Good question, and thanks for noting this is your first post. Welcome to the group, and I hope people will be able to answer your question. Sep 3, 2013 at 17:36

1 Answer 1


Thanks for your question. I'm not an expert in this space, but I asked around and was pointed to two resources at NREL you might look at:

  1. The efficiency curves available in the FASTSim model that are posted at http://www.nrel.gov/fastsim. I was told by the managers of this dataset that it may be used for commercial purposes, just not redistributed commercially.
  2. The Caltrans cleansed dataset will be posted at http://www.nrel.gov/tsdc in the next couple of weeks, which will includes a subset of vehicles where OBD data was recorded along with GPS speed profiles.
  • Wow +1 to the US government for doing projects like this, it's seriously cool. Source 1 had some interesting info but wasn't quite on the mark (firstly the data was for hybrids), but source 2 looks very interesting.. I'll check it out once it's released and get back to you.
    – andrewb
    Sep 14, 2013 at 0:36

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