Topic: Engine efficiency

[Wetson]

After purchasing a new vehicle... at how many KM's does the motor reach it's peak fuel efficiency?  I've got about 9K on my Accord and I've noticed in the last few weeks it's a whole lot better on gas than it was. 

[AVToller]

I think there are a LOT of variables to consider. I kept a spreadsheet on my '94 Golf, and it got it's best mileage just before I sold it at 98+k. Allowing for seasonal variations, it consistently improved over the six years I owned it. I did, however, break it in very gently. Perhaps if I had been a little harder on it, it would have gotten and maintained that higher economy earlier. Oh, and I did notice a significant improvement when I went to synthetic. If I recall correctly, about 4-5%. The majority of my driving was city and fairly short drives at that.

[articsteve]

With current day cars I believe the best efficiency is right off the get go when all the sensors and cats are brand new.  It then slowly slides from point on.

[ovr50]

I think it does vary by vehicle but I know on my recent ones (4Runner, Impreza, RAV4), it took to about 8 or 10k before the engine felt really "good". Have about 4500kms on Highlander and it feels better every day....(leave it alone, Saf).

Didn't do fuel use comparisons but generally think the economy improves then also.

[smainville]

With my X-Trail I achieved what it was rated for at 1000km and still achieve it today at 63,000km.  So at this point I'm not sure if I believe in that as much as I think the brand of fuel can make a difference, my take.

[johngenx]

On my MB, it got better, in tiny increments, until about 100K and it's been steady ever since.  Worst period was from 0 to about 15K.  Of course, I keep it in good tune and it's always had synthetic, so that helps with long run economy.

[tpl]

My 330's fuel consumption, according to the computer got slowly but steadily better for the first 25,000Km... the oil consumption dropped to zero over that period as well.   That 25,000  was starting breakin on a -22 feb day and getting through until a May day one year later, so 1.5 winters  and 1 summer  with appropriate tires for the summer and winter and a driving regime of downtown to buttonville on the dvp/404 and back. TO dwellers will understand exactly the conditions.... 130kph at the north end, 5 kph in the middle and 110 kph at the bottom.  All starts at outside ambient, synth oil throughout.


Now I do firmly agree about the car being better when the sensors are new...better feeling... but getting some tolerance in the clockwork does make everything run a little smoother