View Single Post
Old 04-12-2008, 04:33 AM   #9 (permalink)
EcoModding Lurker
Join Date: Apr 2008
Location: Grand Junction, CO
Posts: 3
Thanks: 0
Thanked 0 Times in 0 Posts
It's called DFCO or Deceleration Fuel Cutoff, when your instantaneous FE goes to zero. . What your fuel injectors do is when your engine is above some threshold rpm (~1500rpm) and you are applying no gas is it completely cuts the gas to the engine and just lets it turn from the car's momentum. However as the engine is still spinning your AC still works. However the AC is still causing drag, so it will shorten your "glide". I use quotes there because if you're P&Ging you should be gliding in neutral. If you're gliding with the engine on in neutral you'll see a significant decrease in FE as a idling engine with AC on uses a lot more gas than without.
  Reply With Quote