Quote:
Originally Posted by amcpacer
That way the engine will be turning at idle speeds and will ingest less air / fuel mix as opposed to a higher rpm deceleration in gear.
|
solid thought, but it may not be correct.
if you clutch it or otherwise put the shifter into a neutral position, you will be turning an idle RPM, but RPM is not the end-all when it comes to efficiency, you have to look at total fuel flow, which you can approximate from airflow.
OP, do you have any way of tracking MAF voltage/frequency? if so, i'd take a look at what happens while engine braking to speed down compared to coasting in neutral, whichever indicates a lower airflow shoud net you better fuel economy. not all vehicles respond the same, so you'll really have to test on your own vehicle to be certain.